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addr and as asm
bind block break
case cast concept const continue converter
defer discard distinct div do
elif else end enum except export
finally for from func
if import in include interface is isnot iterator
let
macro method mixin mod
nil not notin
object of or out
proc ptr
raise ref return
shl shr static
template try tuple type
using
var
when while
xor
yield
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<a href='https://github.com/akkartik/mu/blob/main/boot.subx'>https://github.com/akkartik/mu/blob/main/boot.subx</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr">   1 </span><span class="subxComment"># Code for the first few disk sectors that all programs in this directory need:</span>
<span id="L2" class="LineNr">   2 </span><span class="subxComment">#   - load sectors past the first (using BIOS primitives) since only the first is available by default</span>
<span id="L3" class="LineNr">   3 </span><span class="subxComment">#     - if this fails, print 'D' at top-left of screen and halt</span>
<span id="L4" class="LineNr">   4 </span><span class="subxComment">#   - initialize a minimal graphics mode</span>
<span id="L5" class="LineNr">   5 </span><span class="subxComment">#   - switch to 32-bit mode (giving up access to BIOS primitives)</span>
<span id="L6" class="LineNr">   6 </span><span class="subxComment">#   - set up a handler for keyboard events</span>
<span id="L7" class="LineNr">   7 </span><span class="subxComment">#   - jump to start of program</span>
<span id="L8" class="LineNr">   8 </span>
<span id="L9" class="LineNr">   9 </span><span class="subxComment"># Code in this file needs to be more deliberate about the SubX facilities it</span>
<span id="L10" class="LineNr">  10 </span><span class="subxComment"># uses:</span>
<span id="L11" class="LineNr">  11 </span><span class="subxComment">#   - sigils only support 32-bit general-purpose registers, so don't work with segment registers or 16-bit or 8-bit registers</span>
<span id="L12" class="LineNr">  12 </span><span class="subxComment">#   - metadata like rm32 and r32 can sometimes misleadingly refer to only the bottom 16 bits of the register; pay attention to the register name</span>
<span id="L13" class="LineNr">  13 </span><span class="subxComment">#</span>
<span id="L14" class="LineNr">  14 </span><span class="subxComment"># While most of Mu is thoroughly tested, this file is not. I don't yet</span>
<span id="L15" class="LineNr">  15 </span><span class="subxComment"># understand hardware interfaces well enough to explain to others.</span>
<span id="L16" class="LineNr">  16 </span>
<span id="L17" class="LineNr">  17 </span><span class="subxComment"># Memory map of a Mu computer:</span>
<span id="L18" class="LineNr">  18 </span><span class="subxComment">#   code:         [0x00007c00, 0x0007de00)</span>
<span id="L19" class="LineNr">  19 </span><span class="subxComment">#   system font:  [0x00100000, 0x00f00000)</span>
<span id="L20" class="LineNr">  20 </span><span class="subxComment">#   stack:        (0x02000000, 0x01000000]</span>
<span id="L21" class="LineNr">  21 </span><span class="subxComment">#   heap:         [0x02000000, 0x80000000)</span>
<span id="L22" class="LineNr">  22 </span><span class="subxComment">#     see 120allocate.subx; Qemu initializes with 128MB RAM by default; simulating 2GB RAM is known to work</span>
<span id="L23" class="LineNr">  23 </span><span class="subxComment"># Consult <a href="https://wiki.osdev.org/Memory_Map_(x86)">https://wiki.osdev.org/Memory_Map_(x86)</a> before modifying any of</span>
<span id="L24" class="LineNr">  24 </span><span class="subxComment"># this. And don't forget to keep *stack-debug.subx in sync.</span>
<span id="L25" class="LineNr">  25 </span>
<span id="L26" class="LineNr">  26 </span>== code
<span id="L27" class="LineNr">  27 </span>
<span id="L28" class="LineNr">  28 </span><span class="subxComment">## 16-bit entry point: 0x7c00</span>
<span id="L29" class="LineNr">  29 </span>
<span id="L30" class="LineNr">  30 </span><span class="subxComment"># Upon reset, the IBM PC:</span>
<span id="L31" class="LineNr">  31 </span><span class="subxComment">#   - loads the first sector (512 bytes)</span>
<span id="L32" class="LineNr">  32 </span><span class="subxComment">#     from some bootable image (look for the boot-sector-marker further down this file)</span>
<span id="L33" class="LineNr">  33 </span><span class="subxComment">#     to the address range [0x7c00, 0x7e00)</span>
<span id="L34" class="LineNr">  34 </span><span class="subxComment">#   - starts executing code at address 0x7c00</span>
<span id="L35" class="LineNr">  35 </span>
<span id="L36" class="LineNr">  36 </span>  fa/disable-interrupts
<span id="L37" class="LineNr">  37 </span>
<span id="L38" class="LineNr">  38 </span>  <span class="subxComment"># initialize segment registers</span>
<span id="L39" class="LineNr">  39 </span>  b8/copy-to-ax 0/imm16
<span id="L40" class="LineNr">  40 </span>  8e/-&gt;seg 3/mod/direct 0/rm32/ax 3/r32/ds
<span id="L41" class="LineNr">  41 </span>  8e/-&gt;seg 3/mod/direct 0/rm32/ax 0/r32/es
<span id="L42" class="LineNr">  42 </span>  8e/-&gt;seg 3/mod/direct 0/rm32/ax 4/r32/fs
<span id="L43" class="LineNr">  43 </span>  8e/-&gt;seg 3/mod/direct 0/rm32/ax 5/r32/gs
<span id="L44" class="LineNr">  44 </span>
<span id="L45" class="LineNr">  45 </span>  <span class="subxComment"># Temporarily initialize stack to 0x00070000 in real mode.</span>
<span id="L46" class="LineNr">  46 </span>  <span class="subxComment"># We don't read or write the stack before we get to 32-bit mode, but BIOS</span>
<span id="L47" class="LineNr">  47 </span>  <span class="subxComment"># calls do. We need to move the stack in case BIOS initializes it to some</span>
<span id="L48" class="LineNr">  48 </span>  <span class="subxComment"># low address that we want to write code into.</span>
<span id="L49" class="LineNr">  49 </span>  b8/copy-to-ax 0x7000/imm16
<span id="L50" class="LineNr">  50 </span>  8e/-&gt;seg 3/mod/direct 0/rm32/ax 2/r32/ss
<span id="L51" class="LineNr">  51 </span>  bc/copy-to-esp 0/imm16
<span id="L52" class="LineNr">  52 </span>
<span id="L53" class="LineNr">  53 </span>  <span class="subxComment"># undo the A20 hack: <a href="https://en.wikipedia.org/wiki/A20_line">https://en.wikipedia.org/wiki/A20_line</a></span>
<span id="L54" class="LineNr">  54 </span>  <span class="subxComment"># this is from <a href="https://github.com/mit-pdos/xv6-public/blob/master/bootasm.S">https://github.com/mit-pdos/xv6-public/blob/master/bootasm.S</a></span>
<span id="L55" class="LineNr">  55 </span>  {
<span id="L56" class="LineNr">  56 </span>    e4/read-port-into-al 0x64/imm8
<span id="L57" class="LineNr">  57 </span>    a8/test-bits-in-al 0x02/imm8  <span class="subxComment"># set zf if bit 1 (second-least significant) is not set</span>
<span id="L58" class="LineNr">  58 </span>    75/jump-if-!zero <span class="Constant">loop</span>/disp8
<span id="L59" class="LineNr">  59 </span>    b0/copy-to-al 0xd1/imm8
<span id="L60" class="LineNr">  60 </span>    e6/write-al-into-port 0x64/imm8
<span id="L61" class="LineNr">  61 </span>  }
<span id="L62" class="LineNr">  62 </span>  {
<span id="L63" class="LineNr">  63 </span>    e4/read-port-into-al 0x64/imm8
<span id="L64" class="LineNr">  64 </span>    a8/test-bits-in-al 0x02/imm8  <span class="subxComment"># set zf if bit 1 (second-least significant) is not set</span>
<span id="L65" class="LineNr">  65 </span>    75/jump-if-!zero <span class="Constant">loop</span>/disp8
<span id="L66" class="LineNr">  66 </span>    b0/copy-to-al 0xdf/imm8
<span id="L67" class="LineNr">  67 </span>    e6/write-al-into-port 0x64/imm8
<span id="L68" class="LineNr">  68 </span>  }
<span id="L69" class="LineNr">  69 </span>
<span id="L70" class="LineNr">  70 </span>  <span class="subxComment"># load remaining sectors from first two tracks of disk into addresses [0x7e00, 0x17800)</span>
<span id="L71" class="LineNr">  71 </span>  b4/copy-to-ah 2/imm8/read-drive
<span id="L72" class="LineNr">  72 </span>  <span class="subxComment"># dl comes conveniently initialized at boot time with the index of the device being booted</span>
<span id="L73" class="LineNr">  73 </span>  b5/copy-to-ch 0/imm8/cylinder
<span id="L74" class="LineNr">  74 </span>  b6/copy-to-dh 0/imm8/head                   <span class="subxComment"># &lt;====</span>
<span id="L75" class="LineNr">  75 </span>  b1/copy-to-cl 2/imm8/sector  <span class="subxComment"># 1-based</span>
<span id="L76" class="LineNr">  76 </span>  b0/copy-to-al 0x7d/imm8/num-sectors  <span class="subxComment"># 2*63 - 1 = 125</span>
<span id="L77" class="LineNr">  77 </span>  <span class="subxComment"># address to write sectors to = es:bx = 0x7e00, contiguous with boot segment</span>
<span id="L78" class="LineNr">  78 </span>  bb/copy-to-bx 0/imm16
<span id="L79" class="LineNr">  79 </span>  8e/-&gt;seg 3/mod/direct 3/rm32/bx 0/r32/es
<span id="L80" class="LineNr">  80 </span>  bb/copy-to-bx 0x7e00/imm16                  <span class="subxComment"># &lt;====</span>
<span id="L81" class="LineNr">  81 </span>  cd/syscall 0x13/imm8/bios-disk-services
<span id="L82" class="LineNr">  82 </span>  0f 82/jump-if-carry <a href='boot.subx.html#L220'>disk_error</a>/disp16
<span id="L83" class="LineNr">  83 </span>
<span id="L84" class="LineNr">  84 </span>  <span class="subxComment"># load two more tracks of disk into addresses [0x17800, 0x27400)</span>
<span id="L85" class="LineNr">  85 </span>  b4/copy-to-ah 2/imm8/read-drive
<span id="L86" class="LineNr">  86 </span>  <span class="subxComment"># dl comes conveniently initialized at boot time with the index of the device being booted</span>
<span id="L87" class="LineNr">  87 </span>  b5/copy-to-ch 0/imm8/cylinder
<span id="L88" class="LineNr">  88 </span>  b6/copy-to-dh 2/imm8/head                   <span class="subxComment"># &lt;====</span>
<span id="L89" class="LineNr">  89 </span>  b1/copy-to-cl 1/imm8/sector  <span class="subxComment"># 1-based</span>
<span id="L90" class="LineNr">  90 </span>  b0/copy-to-al 0x7e/imm8/num-sectors  <span class="subxComment"># 2*63 = 126</span>
<span id="L91" class="LineNr">  91 </span>  <span class="subxComment"># address to write sectors to = es:bx = 0x17800, contiguous with boot segment</span>
<span id="L92" class="LineNr">  92 </span>  bb/copy-to-bx 0x1780/imm16                  <span class="subxComment"># &lt;====</span>
<span id="L93" class="LineNr">  93 </span>  8e/-&gt;seg 3/mod/direct 3/rm32/bx 0/r32/es
<span id="L94" class="LineNr">  94 </span>  bb/copy-to-bx 0/imm16
<span id="L95" class="LineNr">  95 </span>  cd/syscall 0x13/imm8/bios-disk-services
<span id="L96" class="LineNr">  96 </span>  0f 82/jump-if-carry <a href='boot.subx.html#L220'>disk_error</a>/disp16
<span id="L97" class="LineNr">  97 </span>
<span id="L98" class="LineNr">  98 </span>  <span class="subxComment"># load two more tracks of disk into addresses [0x27400, 0x37000)</span>
<span id="L99" class="LineNr">  99 </span>  b4/copy-to-ah 2/imm8/read-drive
<span id="L100" class="LineNr"> 100 </span>  <span class="subxComment"># dl comes conveniently initialized at boot time with the index of the device being booted</span>
<span id="L101" class="LineNr"> 101 </span>  b5/copy-to-ch 0/imm8/cylinder
<span id="L102" class="LineNr"> 102 </span>  b6/copy-to-dh 4/imm8/head                   <span class="subxComment"># &lt;====</span>
<span id="L103" class="LineNr"> 103 </span>  b1/copy-to-cl 1/imm8/sector  <span class="subxComment"># 1-based</span>
<span id="L104" class="LineNr"> 104 </span>  b0/copy-to-al 0x7e/imm8/num-sectors  <span class="subxComment"># 2*63 = 126</span>
<span id="L105" class="LineNr"> 105 </span>  <span class="subxComment"># address to write sectors to = es:bx = 0x27400, contiguous with boot segment</span>
<span id="L106" class="LineNr"> 106 </span>  bb/copy-to-bx 0x2740/imm16                  <span class="subxComment"># &lt;====</span>
<span id="L107" class="LineNr"> 107 </span>  8e/-&gt;seg 3/mod/direct 3/rm32/bx 0/r32/es
<span id="L108" class="LineNr"> 108 </span>  bb/copy-to-bx 0/imm16
<span id="L109" class="LineNr"> 109 </span>  cd/syscall 0x13/imm8/bios-disk-services
<span id="L110" class="LineNr"> 110 </span>  0f 82/jump-if-carry <a href='boot.subx.html#L220'>disk_error</a>/disp16
<span id="L111" class="LineNr"> 111 </span>
<span id="L112" class="LineNr"> 112 </span>  <span class="subxComment"># load two more tracks of disk into addresses [0x37000, 0x46c00)</span>
<span id="L113" class="LineNr"> 113 </span>  b4/copy-to-ah 2/imm8/read-drive
<span id="L114" class="LineNr"> 114 </span>  <span class="subxComment"># dl comes conveniently initialized at boot time with the index of the device being booted</span>
<span id="L115" class="LineNr"> 115 </span>  b5/copy-to-ch 0/imm8/cylinder
<span id="L116" class="LineNr"> 116 </span>  b6/copy-to-dh 6/imm8/head                   <span class="subxComment"># &lt;====</span>
<span id="L117" class="LineNr"> 117 </span>  b1/copy-to-cl 1/imm8/sector  <span class="subxComment"># 1-based</span>
<span id="L118" class="LineNr"> 118 </span>  b0/copy-to-al 0x7e/imm8/num-sectors  <span class="subxComment"># 2*63 = 126</span>
<span id="L119" class="LineNr"> 119 </span>  <span class="subxComment"># address to write sectors to = es:bx = 0x37000, contiguous with boot segment</span>
<span id="L120" class="LineNr"> 120 </span>  bb/copy-to-bx 0x3700/imm16                  <span class="subxComment"># &lt;====</span>
<span id="L121" class="LineNr"> 121 </span>  8e/-&gt;seg 3/mod/direct 3/rm32/bx 0/r32/es
<span id="L122" class="LineNr"> 122 </span>  bb/copy-to-bx 0/imm16
<span id="L123" class="LineNr"> 123 </span>  cd/syscall 0x13/imm8/bios-disk-services
<span id="L124" class="LineNr"> 124 </span>  0f 82/jump-if-carry <a href='boot.subx.html#L220'>disk_error</a>/disp16
<span id="L125" class="LineNr"> 125 </span>
<span id="L126" class="LineNr"> 126 </span>  <span class="subxComment"># load two more tracks of disk into addresses [0x46c00, 0x56800)</span>
<span id="L127" class="LineNr"> 127 </span>  b4/copy-to-ah 2/imm8/read-drive
<span id="L128" class="LineNr"> 128 </span>  <span class="subxComment"># dl comes conveniently initialized at boot time with the index of the device being booted</span>
<span id="L129" class="LineNr"> 129 </span>  b5/copy-to-ch 0/imm8/cylinder
<span id="L130" class="LineNr"> 130 </span>  b6/copy-to-dh 8/imm8/head                   <span class="subxComment"># &lt;====</span>
<span id="L131" class="LineNr"> 131 </span>  b1/copy-to-cl 1/imm8/sector  <span class="subxComment"># 1-based</span>
<span id="L132" class="LineNr"> 132 </span>  b0/copy-to-al 0x7e/imm8/num-sectors  <span class="subxComment"># 2*63 = 126</span>
<span id="L133" class="LineNr"> 133 </span>  <span class="subxComment"># address to write sectors to = es:bx = 0x46c00, contiguous with boot segment</span>
<span id="L134" class="LineNr"> 134 </span>  bb/copy-to-bx 0x46c0/imm16                  <span class="subxComment"># &lt;====</span>
<span id="L135" class="LineNr"> 135 </span>  8e/-&gt;seg 3/mod/direct 3/rm32/bx 0/r32/es
<span id="L136" class="LineNr"> 136 </span>  bb/copy-to-bx 0/imm16
<span id="L137" class="LineNr"> 137 </span>  cd/syscall 0x13/imm8/bios-disk-services
<span id="L138" class="LineNr"> 138 </span>  0f 82/jump-if-carry <a href='boot.subx.html#L220'>disk_error</a>/disp16
<span id="L139" class="LineNr"> 139 </span>
<span id="L140" class="LineNr"> 140 </span>  <span class="subxComment"># load two more tracks of disk into addresses [0x56800, 0x66400)</span>
<span id="L141" class="LineNr"> 141 </span>  b4/copy-to-ah 2/imm8/read-drive
<span id="L142" class="LineNr"> 142 </span>  <span class="subxComment"># dl comes conveniently initialized at boot time with the index of the device being booted</span>
<span id="L143" class="LineNr"> 143 </span>  b5/copy-to-ch 0/imm8/cylinder
<span id="L144" class="LineNr"> 144 </span>  b6/copy-to-dh 0xa/imm8/head                 <span class="subxComment"># &lt;====</span>
<span id="L145" class="LineNr"> 145 </span>  b1/copy-to-cl 1/imm8/sector  <span class="subxComment"># 1-based</span>
<span id="L146" class="LineNr"> 146 </span>  b0/copy-to-al 0x7e/imm8/num-sectors  <span class="subxComment"># 2*63 = 126</span>
<span id="L147" class="LineNr"> 147 </span>  <span class="subxComment"># address to write sectors to = es:bx = 0x56800, contiguous with boot segment</span>
<span id="L148" class="LineNr"> 148 </span>  bb/copy-to-bx 0x5680/imm16                  <span class="subxComment"># &lt;====</span>
<span id="L149" class="LineNr"> 149 </span>  8e/-&gt;seg 3/mod/direct 3/rm32/bx 0/r32/es
<span id="L150" class="LineNr"> 150 </span>  bb/copy-to-bx 0/imm16
<span id="L151" class="LineNr"> 151 </span>  cd/syscall 0x13/imm8/bios-disk-services
<span id="L152" class="LineNr"> 152 </span>  0f 82/jump-if-carry <a href='boot.subx.html#L220'>disk_error</a>/disp16
<span id="L153" class="LineNr"> 153 </span>
<span id="L154" class="LineNr"> 154 </span>  <span class="subxComment"># load two more tracks of disk into addresses [0x66400, 0x76000)</span>
<span id="L155" class="LineNr"> 155 </span>  b4/copy-to-ah 2/imm8/read-drive
<span id="L156" class="LineNr"> 156 </span>  <span class="subxComment"># dl comes conveniently initialized at boot time with the index of the device being booted</span>
<span id="L157" class="LineNr"> 157 </span>  b5/copy-to-ch 0/imm8/cylinder
<span id="L158" class="LineNr"> 158 </span>  b6/copy-to-dh 0xc/imm8/head                 <span class="subxComment"># &lt;====</span>
<span id="L159" class="LineNr"> 159 </span>  b1/copy-to-cl 1/imm8/sector  <span class="subxComment"># 1-based</span>
<span id="L160" class="LineNr"> 160 </span>  b0/copy-to-al 0x7e/imm8/num-sectors  <span class="subxComment"># 2*63 = 126</span>
<span id="L161" class="LineNr"> 161 </span>  <span class="subxComment"># address to write sectors to = es:bx = 0x56800, contiguous with boot segment</span>
<span id="L162" class="LineNr"> 162 </span>  bb/copy-to-bx 0x6640/imm16                  <span class="subxComment"># &lt;====</span>
<span id="L163" class="LineNr"> 163 </span>  8e/-&gt;seg 3/mod/direct 3/rm32/bx 0/r32/es
<span id="L164" class="LineNr"> 164 </span>  bb/copy-to-bx 0/imm16
<span id="L165" class="LineNr"> 165 </span>  cd/syscall 0x13/imm8/bios-disk-services
<span id="L166" class="LineNr"> 166 </span>  0f 82/jump-if-carry <a href='boot.subx.html#L220'>disk_error</a>/disp16
<span id="L167" class="LineNr"> 167 </span>
<span id="L168" class="LineNr"> 168 </span>  <span class="subxComment"># load one final track of disk into addresses [0x76000, 0x7de00)</span>
<span id="L169" class="LineNr"> 169 </span>  b4/copy-to-ah 2/imm8/read-drive
<span id="L170" class="LineNr"> 170 </span>  <span class="subxComment"># dl comes conveniently initialized at boot time with the index of the device being booted</span>
<span id="L171" class="LineNr"> 171 </span>  b5/copy-to-ch 0/imm8/cylinder
<span id="L172" class="LineNr"> 172 </span>  b6/copy-to-dh 0xe/imm8/head                 <span class="subxComment"># &lt;====</span>
<span id="L173" class="LineNr"> 173 </span>  b1/copy-to-cl 1/imm8/sector  <span class="subxComment"># 1-based</span>
<span id="L174" class="LineNr"> 174 </span>  b0/copy-to-al 0x3f/imm8/num-sectors=63
<span id="L175" class="LineNr"> 175 </span>  <span class="subxComment"># address to write sectors to = es:bx = 0x56800, contiguous with boot segment</span>
<span id="L176" class="LineNr"> 176 </span>  bb/copy-to-bx 0x7600/imm16                  <span class="subxComment"># &lt;====</span>
<span id="L177" class="LineNr"> 177 </span>  8e/-&gt;seg 3/mod/direct 3/rm32/bx 0/r32/es
<span id="L178" class="LineNr"> 178 </span>  bb/copy-to-bx 0/imm16
<span id="L179" class="LineNr"> 179 </span>  cd/syscall 0x13/imm8/bios-disk-services
<span id="L180" class="LineNr"> 180 </span>  0f 82/jump-if-carry <a href='boot.subx.html#L220'>disk_error</a>/disp16
<span id="L181" class="LineNr"> 181 </span>
<span id="L182" class="LineNr"> 182 </span>  <span class="subxComment">### Loading more code tracks would clobber BIOS; we need a new compilation strategy.</span>
<span id="L183" class="LineNr"> 183 </span>
<span id="L184" class="LineNr"> 184 </span>  <span class="subxComment"># reset es</span>
<span id="L185" class="LineNr"> 185 </span>  bb/copy-to-bx 0/imm16
<span id="L186" class="LineNr"> 186 </span>  8e/-&gt;seg 3/mod/direct 3/rm32/bx 0/r32/es
<span id="L187" class="LineNr"> 187 </span>
<span id="L188" class="LineNr"> 188 </span>  <span class="subxComment"># adjust video mode</span>
<span id="L189" class="LineNr"> 189 </span>  b4/copy-to-ah 0x4f/imm8  <span class="subxComment"># VBE commands</span>
<span id="L190" class="LineNr"> 190 </span>  b0/copy-to-al 2/imm8  <span class="subxComment"># set video mode</span>
<span id="L191" class="LineNr"> 191 </span>  bb/copy-to-bx 0x4105/imm16  <span class="subxComment"># 0x0105 | 0x4000</span>
<span id="L192" class="LineNr"> 192 </span>                              <span class="subxComment"># 0x0105 = graphics mode 1024x768x256</span>
<span id="L193" class="LineNr"> 193 </span>                              <span class="subxComment">#  (alternative candidate: 0x0101 for 640x480x256)</span>
<span id="L194" class="LineNr"> 194 </span>                              <span class="subxComment"># 0x4000 bit = configure linear frame buffer in Bochs emulator; hopefully this doesn't hurt anything when running natively</span>
<span id="L195" class="LineNr"> 195 </span>  cd/syscall 0x10/imm8/bios-video-services
<span id="L196" class="LineNr"> 196 </span>
<span id="L197" class="LineNr"> 197 </span>  <span class="subxComment"># load information for the (hopefully) current video mode</span>
<span id="L198" class="LineNr"> 198 </span>  <span class="subxComment"># mostly just for the address to the linear frame buffer</span>
<span id="L199" class="LineNr"> 199 </span>  b4/copy-to-ah 0x4f/imm8  <span class="subxComment"># VBE commands</span>
<span id="L200" class="LineNr"> 200 </span>  b0/copy-to-al 1/imm8  <span class="subxComment"># get video mode info</span>
<span id="L201" class="LineNr"> 201 </span>  b9/copy-to-cx 0x0105/imm16  <span class="subxComment"># mode we requested</span>
<span id="L202" class="LineNr"> 202 </span>  bf/copy-to-di <span class="SpecialChar"><a href='boot.subx.html#L641'>Video-mode-info</a></span>/imm16
<span id="L203" class="LineNr"> 203 </span>  cd/syscall 0x10/imm8/bios-video-services
<span id="L204" class="LineNr"> 204 </span>
<span id="L205" class="LineNr"> 205 </span>  <span class="subxComment">## switch to 32-bit mode</span>
<span id="L206" class="LineNr"> 206 </span>  <span class="subxComment"># load global descriptor table</span>
<span id="L207" class="LineNr"> 207 </span>  <span class="subxComment"># We can't refer to the label directly because SubX doesn't do the right</span>
<span id="L208" class="LineNr"> 208 </span>  <span class="subxComment"># thing for lgdt, so rather than make errors worse in most places we instead</span>
<span id="L209" class="LineNr"> 209 </span>  <span class="subxComment"># pin gdt_descriptor below.</span>
<span id="L210" class="LineNr"> 210 </span>  0f 01 2/subop/lgdt 0/mod/indirect 6/rm32/use-disp16 0x7de0/disp16/gdt_descriptor
<span id="L211" class="LineNr"> 211 </span>  <span class="subxComment"># enable paging</span>
<span id="L212" class="LineNr"> 212 </span>  0f 20/&lt;-cr 3/mod/direct 0/rm32/eax 0/r32/cr0
<span id="L213" class="LineNr"> 213 </span>  66 83 1/subop/or 3/mod/direct 0/rm32/eax 1/imm8  <span class="subxComment"># eax &lt;- or 0x1</span>
<span id="L214" class="LineNr"> 214 </span>  0f 22/-&gt;cr 3/mod/direct 0/rm32/eax 0/r32/cr0
<span id="L215" class="LineNr"> 215 </span>  <span class="subxComment"># far jump to initialize_32bit_mode that sets cs to offset 8 in the gdt in the process</span>
<span id="L216" class="LineNr"> 216 </span>  <span class="subxComment"># We can't refer to the label directly because SubX doesn't have syntax for</span>
<span id="L217" class="LineNr"> 217 </span>  <span class="subxComment"># segment selectors. So we instead pin initialize_32bit_mode below.</span>
<span id="L218" class="LineNr"> 218 </span>  ea/jump-far-absolute 0x00087e00/disp32  <span class="subxComment"># address 0x7e00 in offset 8 of the gdt</span>
<span id="L219" class="LineNr"> 219 </span>
<span id="L220" class="LineNr"> 220 </span><span class="subxFunction">disk_error</span>:
<span id="L221" class="LineNr"> 221 </span>  <span class="subxComment"># print 'D' to top-left of screen to indicate disk error</span>
<span id="L222" class="LineNr"> 222 </span>  <span class="subxComment"># *0xb8000 &lt;- 0x0f44</span>
<span id="L223" class="LineNr"> 223 </span>  bb/copy-to-bx 0xb800/imm16
<span id="L224" class="LineNr"> 224 </span>  8e/-&gt;seg 3/mod/direct 3/rm32/bx 3/r32/ds
<span id="L225" class="LineNr"> 225 </span>  b0/copy-to-al 0x44/imm8/D
<span id="L226" class="LineNr"> 226 </span>  b4/copy-to-ah 0x0f/imm8/white-on-black
<span id="L227" class="LineNr"> 227 </span>  bb/copy-to-bx 0/imm16
<span id="L228" class="LineNr"> 228 </span>  89/&lt;- 0/mod/indirect 7/rm32/bx 0/r32/ax  <span class="subxComment"># *ds:bx &lt;- ax</span>
<span id="L229" class="LineNr"> 229 </span>  <span class="subxComment"># loop forever</span>
<span id="L230" class="LineNr"> 230 </span>  {
<span id="L231" class="LineNr"> 231 </span>    eb/jump <span class="Constant">loop</span>/disp8
<span id="L232" class="LineNr"> 232 </span>  }
<span id="L233" class="LineNr"> 233 </span>
<span id="L234" class="LineNr"> 234 </span><span class="subxComment">## GDT: 3 records of 8 bytes each</span>
<span id="L235" class="LineNr"> 235 </span>== data 0x7de0
<span id="L236" class="LineNr"> 236 </span><span class="subxFunction">gdt_descriptor</span>:
<span id="L237" class="LineNr"> 237 </span>  0x17/imm16  <span class="subxComment"># final index of gdt = size of gdt - 1</span>
<span id="L238" class="LineNr"> 238 </span>  <a href='boot.subx.html#L240'>gdt_start</a>/imm32/start
<span id="L239" class="LineNr"> 239 </span>
<span id="L240" class="LineNr"> 240 </span><span class="subxFunction">gdt_start</span>:
<span id="L241" class="LineNr"> 241 </span><span class="subxComment"># offset 0: gdt_null:  mandatory null descriptor</span>
<span id="L242" class="LineNr"> 242 </span>  00 00 00 00 00 00 00 00
<span id="L243" class="LineNr"> 243 </span><span class="subxComment"># offset 8: gdt_code</span>
<span id="L244" class="LineNr"> 244 </span>  ff ff  <span class="subxComment"># limit[0:16]</span>
<span id="L245" class="LineNr"> 245 </span>  00 00 00  <span class="subxComment"># base[0:24]</span>
<span id="L246" class="LineNr"> 246 </span>  9a  <span class="subxComment"># 1/present 00/privilege 1/descriptor type = 1001b</span>
<span id="L247" class="LineNr"> 247 </span>      <span class="subxComment"># 1/code 0/conforming 1/readable 0/accessed = 1010b</span>
<span id="L248" class="LineNr"> 248 </span>  cf  <span class="subxComment"># 1/granularity 1/32-bit 0/64-bit-segment 0/AVL = 1100b</span>
<span id="L249" class="LineNr"> 249 </span>      <span class="subxComment"># limit[16:20] = 1111b</span>
<span id="L250" class="LineNr"> 250 </span>  00  <span class="subxComment"># base[24:32]</span>
<span id="L251" class="LineNr"> 251 </span><span class="subxComment"># offset 16: gdt_data</span>
<span id="L252" class="LineNr"> 252 </span>  ff ff  <span class="subxComment"># limit[0:16]</span>
<span id="L253" class="LineNr"> 253 </span>  00 00 00  <span class="subxComment"># base[0:24]</span>
<span id="L254" class="LineNr"> 254 </span>  92  <span class="subxComment"># 1/present 00/privilege 1/descriptor type = 1001b</span>
<span id="L255" class="LineNr"> 255 </span>      <span class="subxComment"># 0/data 0/conforming 1/readable 0/accessed = 0010b</span>
<span id="L256" class="LineNr"> 256 </span>  cf  <span class="subxComment"># same as gdt_code</span>
<span id="L257" class="LineNr"> 257 </span>  00  <span class="subxComment"># base[24:32]</span>
<span id="L258" class="LineNr"> 258 </span><span class="subxComment"># gdt_end:</span>
<span id="L259" class="LineNr"> 259 </span>
<span id="L260" class="LineNr"> 260 </span>== boot-sector-marker 0x7dfe
<span id="L261" class="LineNr"> 261 </span><span class="subxComment"># final 2 bytes of boot sector</span>
<span id="L262" class="LineNr"> 262 </span>55 aa
<span id="L263" class="LineNr"> 263 </span>
<span id="L264" class="LineNr"> 264 </span><span class="subxComment">## sector 2 onwards loaded by load_disk, not automatically on boot</span>
<span id="L265" class="LineNr"> 265 </span>
<span id="L266" class="LineNr"> 266 </span><span class="subxComment">## 32-bit code from this point</span>
<span id="L267" class="LineNr"> 267 </span>
<span id="L268" class="LineNr"> 268 </span>== code 0x7e00
<span id="L269" class="LineNr"> 269 </span><span class="subxFunction">initialize_32bit_mode</span>:
<span id="L270" class="LineNr"> 270 </span>  66 b8/copy-to-ax 0x10/imm16  <span class="subxComment"># offset 16 from gdt_start</span>
<span id="L271" class="LineNr"> 271 </span>  8e/-&gt;seg 3/mod/direct 0/rm32/ax 3/r32/ds
<span id="L272" class="LineNr"> 272 </span>  8e/-&gt;seg 3/mod/direct 0/rm32/ax 2/r32/ss
<span id="L273" class="LineNr"> 273 </span>  8e/-&gt;seg 3/mod/direct 0/rm32/ax 0/r32/es
<span id="L274" class="LineNr"> 274 </span>  8e/-&gt;seg 3/mod/direct 0/rm32/ax 4/r32/fs
<span id="L275" class="LineNr"> 275 </span>  8e/-&gt;seg 3/mod/direct 0/rm32/ax 5/r32/gs
<span id="L276" class="LineNr"> 276 </span>
<span id="L277" class="LineNr"> 277 </span>  bc/copy-to-esp 0x02000000/imm32
<span id="L278" class="LineNr"> 278 </span>
<span id="L279" class="LineNr"> 279 </span>  <span class="subxComment">## install the font somewhere non-contiguous (keep sync'd with memory map up top)</span>
<span id="L280" class="LineNr"> 280 </span>  c7 0/subop/copy *0x00100000 0/imm32/read
<span id="L281" class="LineNr"> 281 </span>  c7 0/subop/copy *0x00100004 0/imm32/write
<span id="L282" class="LineNr"> 282 </span>  c7 0/subop/copy *0x00100008 0x00e00000/imm32/size
<span id="L283" class="LineNr"> 283 </span>  (<a href='510disk.mu.html#L1'>load-sectors</a> <span class="SpecialChar"><a href='boot.subx.html#L709'>Primary-bus-primary-drive</a></span> 0x2328 0x200 0x00100000)   <span class="subxComment"># source 0x2328 = sector 9000 on disk, destination 0x00100000</span>
<span id="L284" class="LineNr"> 284 </span>  <span class="subxComment"># Font is now loaded starting at 0x0010000c.</span>
<span id="L285" class="LineNr"> 285 </span>
<span id="L286" class="LineNr"> 286 </span>  <span class="subxComment">## load interrupt handlers</span>
<span id="L287" class="LineNr"> 287 </span>  <span class="subxComment"># We can't refer to the label directly because SubX doesn't do the right</span>
<span id="L288" class="LineNr"> 288 </span>  <span class="subxComment"># thing for lidt, so rather than make errors worse in most places we instead</span>
<span id="L289" class="LineNr"> 289 </span>  <span class="subxComment"># pin idt_descriptor below.</span>
<span id="L290" class="LineNr"> 290 </span>  0f 01 3/subop/lidt 0/mod/indirect 5/rm32/use-disp32 0x7f00/disp32/idt_descriptor
<span id="L291" class="LineNr"> 291 </span>
<span id="L292" class="LineNr"> 292 </span>  <span class="subxComment"># For now, not bothering reprogramming the IRQ to not conflict with software</span>
<span id="L293" class="LineNr"> 293 </span>  <span class="subxComment"># exceptions.</span>
<span id="L294" class="LineNr"> 294 </span>  <span class="subxComment">#   <a href="https://wiki.osdev.org/index.php?title=8259_PIC&amp;oldid=24650#Protected_Mode">https://wiki.osdev.org/index.php?title=8259_PIC&amp;oldid=24650#Protected_Mode</a></span>
<span id="L295" class="LineNr"> 295 </span>  <span class="subxComment">#</span>
<span id="L296" class="LineNr"> 296 </span>  <span class="subxComment"># Interrupt 1 (keyboard) conflicts with debugger faults. We don't use a</span>
<span id="L297" class="LineNr"> 297 </span>  <span class="subxComment"># debugger.</span>
<span id="L298" class="LineNr"> 298 </span>  <span class="subxComment"># Reference:</span>
<span id="L299" class="LineNr"> 299 </span>  <span class="subxComment">#   <a href="https://wiki.osdev.org/Exceptions">https://wiki.osdev.org/Exceptions</a></span>
<span id="L300" class="LineNr"> 300 </span>
<span id="L301" class="LineNr"> 301 </span>  <span class="subxComment"># enable timer IRQ0 and keyboard IRQ1</span>
<span id="L302" class="LineNr"> 302 </span>  b0/copy-to-al 0xfc/imm8  <span class="subxComment"># disable mask for IRQ0 and IRQ1</span>
<span id="L303" class="LineNr"> 303 </span>  e6/write-al-into-port 0x21/imm8
<span id="L304" class="LineNr"> 304 </span>
<span id="L305" class="LineNr"> 305 </span>  fb/enable-interrupts
<span id="L306" class="LineNr"> 306 </span>
<span id="L307" class="LineNr"> 307 </span>  (<a href='boot.subx.html#L1314'>initialize-mouse</a>)
<span id="L308" class="LineNr"> 308 </span>
<span id="L309" class="LineNr"> 309 </span>  <span class="subxComment">## enable floating point</span>
<span id="L310" class="LineNr"> 310 </span>  db/floating-point-coprocessor e3/initialize
<span id="L311" class="LineNr"> 311 </span>  <span class="subxComment"># eax &lt;- cr4</span>
<span id="L312" class="LineNr"> 312 </span>  0f 20/&lt;-cr 3/mod/direct 0/rm32/eax 4/r32/cr4
<span id="L313" class="LineNr"> 313 </span>  <span class="subxComment"># eax &lt;- or bit 9</span>
<span id="L314" class="LineNr"> 314 </span>  0f ba/bit-test 5/subop/bit-test-and-set 3/mod/direct 0/rm32/eax 9/imm8
<span id="L315" class="LineNr"> 315 </span>  <span class="subxComment"># cr4 &lt;- eax</span>
<span id="L316" class="LineNr"> 316 </span>  0f 22/-&gt;cr 3/mod/direct 0/rm32/eax 4/r32/cr4
<span id="L317" class="LineNr"> 317 </span>
<span id="L318" class="LineNr"> 318 </span>  e9/jump <span class="SpecialChar">Entry</span>/disp32
<span id="L319" class="LineNr"> 319 </span>
<span id="L320" class="LineNr"> 320 </span>== data 0x7f00
<span id="L321" class="LineNr"> 321 </span><span class="subxFunction">idt_descriptor</span>:
<span id="L322" class="LineNr"> 322 </span>  ff 03  <span class="subxComment"># final index of idt = size of idt - 1</span>
<span id="L323" class="LineNr"> 323 </span>  <a href='boot.subx.html#L327'>idt_start</a>/imm32/start
<span id="L324" class="LineNr"> 324 </span>
<span id="L325" class="Folded"> 325 </span><span class="Folded">+-- 55 lines: # interrupt descriptor table --------------------------------------------------------------------------------------------------------------------------------------------</span>
<span id="L380" class="LineNr"> 380 </span>
<span id="L381" class="LineNr"> 381 </span>== code
<span id="L382" class="LineNr"> 382 </span>
<span id="L383" class="LineNr"> 383 </span><span class="subxFunction">timer-interrupt-handler</span>:
<span id="L384" class="LineNr"> 384 </span>  <span class="subxComment"># prologue</span>
<span id="L385" class="LineNr"> 385 </span>  fa/disable-interrupts
<span id="L386" class="LineNr"> 386 </span>  60/push-all-registers
<span id="L387" class="LineNr"> 387 </span>  9c/push-flags
<span id="L388" class="LineNr"> 388 </span>  <span class="subxComment"># acknowledge interrupt</span>
<span id="L389" class="LineNr"> 389 </span>  b0/copy-to-al 0x20/imm8
<span id="L390" class="LineNr"> 390 </span>  e6/write-al-into-port 0x20/imm8
<span id="L391" class="LineNr"> 391 </span>  31/xor %eax 0/r32/eax
<span id="L392" class="LineNr"> 392 </span>  <span class="subxComment"># update *Timer-current-color</span>
<span id="L393" class="LineNr"> 393 </span>  ff 0/subop/increment *<span class="SpecialChar"><a href='boot.subx.html#L402'>Timer-counter</a></span>
<span id="L394" class="LineNr"> 394 </span><span class="Constant">$timer-interrupt-handler:epilogue</span>:
<span id="L395" class="LineNr"> 395 </span>  <span class="subxComment"># epilogue</span>
<span id="L396" class="LineNr"> 396 </span>  9d/pop-flags
<span id="L397" class="LineNr"> 397 </span>  61/pop-all-registers
<span id="L398" class="LineNr"> 398 </span>  fb/enable-interrupts
<span id="L399" class="LineNr"> 399 </span>  cf/return-from-interrupt
<span id="L400" class="LineNr"> 400 </span>
<span id="L401" class="LineNr"> 401 </span>== data
<span id="L402" class="LineNr"> 402 </span><span class="SpecialChar">Timer-counter</span>:
<span id="L403" class="LineNr"> 403 </span>  0/imm32
<span id="L404" class="LineNr"> 404 </span>
<span id="L405" class="LineNr"> 405 </span>== code
<span id="L406" class="LineNr"> 406 </span><span class="subxFunction">keyboard-interrupt-handler</span>:
<span id="L407" class="LineNr"> 407 </span>  <span class="subxComment"># prologue</span>
<span id="L408" class="LineNr"> 408 </span>  fa/disable-interrupts
<span id="L409" class="LineNr"> 409 </span>  60/push-all-registers
<span id="L410" class="LineNr"> 410 </span>  9c/push-flags
<span id="L411" class="LineNr"> 411 </span>  <span class="subxComment"># acknowledge interrupt</span>
<span id="L412" class="LineNr"> 412 </span>  b0/copy-to-al 0x20/imm8
<span id="L413" class="LineNr"> 413 </span>  e6/write-al-into-port 0x20/imm8
<span id="L414" class="LineNr"> 414 </span>  31/xor %eax 0/r32/eax
<span id="L415" class="LineNr"> 415 </span>  <span class="subxComment"># check output buffer of 8042 keyboard controller (<a href="https://web.archive.org/web/20040604041507/http://panda.cs.ndsu.nodak.edu/~achapwes/PICmicro/keyboard/atkeyboard.html)">https://web.archive.org/web/20040604041507/http://panda.cs.ndsu.nodak.edu/~achapwes/PICmicro/keyboard/atkeyboard.html)</a></span>
<span id="L416" class="LineNr"> 416 </span>  e4/read-port-into-al 0x64/imm8
<span id="L417" class="LineNr"> 417 </span>  a8/test-bits-in-al 0x01/imm8  <span class="subxComment"># set zf if bit 0 (least significant) is not set</span>
<span id="L418" class="LineNr"> 418 </span>  0f 84/jump-if-not-set $keyboard-interrupt-handler:end/disp32
<span id="L419" class="LineNr"> 419 </span>  <span class="subxH1Comment"># - if keyboard buffer is full, return</span>
<span id="L420" class="LineNr"> 420 </span>  <span class="subxComment"># var dest-addr/ecx: (addr byte) = (keyboard-buffer + *keyboard-buffer:write)</span>
<span id="L421" class="LineNr"> 421 </span>  31/xor %ecx 1/r32/ecx
<span id="L422" class="LineNr"> 422 </span>  8a/byte-&gt; *<span class="SpecialChar">Keyboard-buffer</span>:<a href='108write.subx.html#L11'>write</a> 1/r32/cl
<span id="L423" class="LineNr"> 423 </span>  81 0/subop/add %ecx <span class="SpecialChar">Keyboard-buffer</span>:data/imm32
<span id="L424" class="LineNr"> 424 </span>  <span class="subxComment"># al = *dest-addr</span>
<span id="L425" class="LineNr"> 425 </span>  8a/byte-&gt; *ecx 0/r32/al
<span id="L426" class="LineNr"> 426 </span>  <span class="subxComment"># if (al != 0) return</span>
<span id="L427" class="LineNr"> 427 </span>  3c/compare-al-and 0/imm8
<span id="L428" class="LineNr"> 428 </span>  0f 85/jump-if-!= $keyboard-interrupt-handler:end/disp32
<span id="L429" class="LineNr"> 429 </span>  <span class="subxH1Comment"># - read keycode</span>
<span id="L430" class="LineNr"> 430 </span>  e4/read-port-into-al 0x60/imm8
<span id="L431" class="LineNr"> 431 </span>  <span class="subxH1Comment"># - key released</span>
<span id="L432" class="LineNr"> 432 </span>  <span class="subxComment"># if (al == 0xaa) shift = false  # left shift is being lifted</span>
<span id="L433" class="LineNr"> 433 </span>  {
<span id="L434" class="LineNr"> 434 </span>    3c/compare-al-and 0xaa/imm8
<span id="L435" class="LineNr"> 435 </span>    75/jump-if-!= <span class="Constant">break</span>/disp8
<span id="L436" class="LineNr"> 436 </span>    <span class="subxComment"># *shift = 0</span>
<span id="L437" class="LineNr"> 437 </span>    c7 0/subop/copy *Keyboard-shift-pressed? 0/imm32
<span id="L438" class="LineNr"> 438 </span>  }
<span id="L439" class="LineNr"> 439 </span>  <span class="subxComment"># if (al == 0xb6) shift = false  # right shift is being lifted</span>
<span id="L440" class="LineNr"> 440 </span>  {
<span id="L441" class="LineNr"> 441 </span>    3c/compare-al-and 0xb6/imm8
<span id="L442" class="LineNr"> 442 </span>    75/jump-if-!= <span class="Constant">break</span>/disp8
<span id="L443" class="LineNr"> 443 </span>    <span class="subxComment"># *shift = 0</span>
<span id="L444" class="LineNr"> 444 </span>    c7 0/subop/copy *Keyboard-shift-pressed? 0/imm32
<span id="L445" class="LineNr"> 445 </span>  }
<span id="L446" class="LineNr"> 446 </span>  <span class="subxComment"># if (al == 0x9d) ctrl = false  # ctrl is being lifted</span>
<span id="L447" class="LineNr"> 447 </span>  {
<span id="L448" class="LineNr"> 448 </span>    3c/compare-al-and 0x9d/imm8
<span id="L449" class="LineNr"> 449 </span>    75/jump-if-!= <span class="Constant">break</span>/disp8
<span id="L450" class="LineNr"> 450 </span>    <span class="subxComment"># *ctrl = 0</span>
<span id="L451" class="LineNr"> 451 </span>    c7 0/subop/copy *Keyboard-ctrl-pressed? 0/imm32
<span id="L452" class="LineNr"> 452 </span>  }
<span id="L453" class="LineNr"> 453 </span>  <span class="subxComment"># if (al &amp; 0x80) a key is being lifted; return</span>
<span id="L454" class="LineNr"> 454 </span>  50/push-eax
<span id="L455" class="LineNr"> 455 </span>  24/and-al-with 0x80/imm8
<span id="L456" class="LineNr"> 456 </span>  3c/compare-al-and 0/imm8
<span id="L457" class="LineNr"> 457 </span>  58/pop-to-eax
<span id="L458" class="LineNr"> 458 </span>  75/jump-if-!= $keyboard-interrupt-handler:end/disp8
<span id="L459" class="LineNr"> 459 </span>  <span class="subxH1Comment"># - key pressed</span>
<span id="L460" class="LineNr"> 460 </span>  <span class="subxComment"># if (al == 0x2a) shift = true, return  # left shift pressed</span>
<span id="L461" class="LineNr"> 461 </span>  {
<span id="L462" class="LineNr"> 462 </span>    3c/compare-al-and 0x2a/imm8
<span id="L463" class="LineNr"> 463 </span>    75/jump-if-!= <span class="Constant">break</span>/disp8
<span id="L464" class="LineNr"> 464 </span>    <span class="subxComment"># *shift = 1</span>
<span id="L465" class="LineNr"> 465 </span>    c7 0/subop/copy *Keyboard-shift-pressed? 1/imm32
<span id="L466" class="LineNr"> 466 </span>    <span class="subxComment"># return</span>
<span id="L467" class="LineNr"> 467 </span>    eb/jump $keyboard-interrupt-handler:end/disp8
<span id="L468" class="LineNr"> 468 </span>  }
<span id="L469" class="LineNr"> 469 </span>  <span class="subxComment"># if (al == 0x36) shift = true, return  # right shift pressed</span>
<span id="L470" class="LineNr"> 470 </span>  {
<span id="L471" class="LineNr"> 471 </span>    3c/compare-al-and 0x36/imm8
<span id="L472" class="LineNr"> 472 </span>    75/jump-if-!= <span class="Constant">break</span>/disp8
<span id="L473" class="LineNr"> 473 </span>    <span class="subxComment"># *shift = 1</span>
<span id="L474" class="LineNr"> 474 </span>    c7 0/subop/copy *Keyboard-shift-pressed? 1/imm32
<span id="L475" class="LineNr"> 475 </span>    <span class="subxComment"># return</span>
<span id="L476" class="LineNr"> 476 </span>    eb/jump $keyboard-interrupt-handler:end/disp8
<span id="L477" class="LineNr"> 477 </span>  }
<span id="L478" class="LineNr"> 478 </span>  <span class="subxComment"># if (al == 0x1d) ctrl = true, return</span>
<span id="L479" class="LineNr"> 479 </span>  {
<span id="L480" class="LineNr"> 480 </span>    3c/compare-al-and 0x1d/imm8
<span id="L481" class="LineNr"> 481 </span>    75/jump-if-!= <span class="Constant">break</span>/disp8
<span id="L482" class="LineNr"> 482 </span>    <span class="subxComment"># *ctrl = 1</span>
<span id="L483" class="LineNr"> 483 </span>    c7 0/subop/copy *Keyboard-ctrl-pressed? 1/imm32
<span id="L484" class="LineNr"> 484 </span>    <span class="subxComment"># return</span>
<span id="L485" class="LineNr"> 485 </span>    eb/jump $keyboard-interrupt-handler:end/disp8
<span id="L486" class="LineNr"> 486 </span>  }
<span id="L487" class="LineNr"> 487 </span>  <span class="subxH1Comment"># - convert key to character</span>
<span id="L488" class="LineNr"> 488 </span>  <span class="subxComment"># if (shift) use keyboard shift map</span>
<span id="L489" class="LineNr"> 489 </span>  {
<span id="L490" class="LineNr"> 490 </span>    81 7/subop/compare *Keyboard-shift-pressed? 0/imm32
<span id="L491" class="LineNr"> 491 </span>    74/jump-if-= <span class="Constant">break</span>/disp8
<span id="L492" class="LineNr"> 492 </span>    <span class="subxComment"># sigils don't currently support labels inside *(eax+label)</span>
<span id="L493" class="LineNr"> 493 </span>    05/add-to-eax <span class="SpecialChar"><a href='boot.subx.html#L580'>Keyboard-shift-map</a></span>/imm32
<span id="L494" class="LineNr"> 494 </span>    8a/byte-&gt; *eax 0/r32/al
<span id="L495" class="LineNr"> 495 </span>    eb/jump $keyboard-interrupt-handler:select-map-done/disp8
<span id="L496" class="LineNr"> 496 </span>  }
<span id="L497" class="LineNr"> 497 </span>  <span class="subxComment"># if (ctrl) al = *(ctrl map + al)</span>
<span id="L498" class="LineNr"> 498 </span>  {
<span id="L499" class="LineNr"> 499 </span>    81 7/subop/compare *Keyboard-ctrl-pressed? 0/imm32
<span id="L500" class="LineNr"> 500 </span>    74/jump-if-= <span class="Constant">break</span>/disp8
<span id="L501" class="LineNr"> 501 </span>    05/add-to-eax <span class="SpecialChar"><a href='boot.subx.html#L612'>Keyboard-ctrl-map</a></span>/imm32
<span id="L502" class="LineNr"> 502 </span>    8a/byte-&gt; *eax 0/r32/al
<span id="L503" class="LineNr"> 503 </span>    eb/jump $keyboard-interrupt-handler:select-map-done/disp8
<span id="L504" class="LineNr"> 504 </span>  }
<span id="L505" class="LineNr"> 505 </span>  <span class="subxComment"># otherwise al = *(normal map + al)</span>
<span id="L506" class="LineNr"> 506 </span>  05/add-to-eax <span class="SpecialChar"><a href='boot.subx.html#L546'>Keyboard-normal-map</a></span>/imm32
<span id="L507" class="LineNr"> 507 </span>  8a/byte-&gt; *eax 0/r32/al
<span id="L508" class="LineNr"> 508 </span><span class="Constant">$keyboard-interrupt-handler:select-map-done</span>:
<span id="L509" class="LineNr"> 509 </span>  <span class="subxH1Comment"># - if there's no character mapping, return</span>
<span id="L510" class="LineNr"> 510 </span>  {
<span id="L511" class="LineNr"> 511 </span>    3c/compare-al-and 0/imm8
<span id="L512" class="LineNr"> 512 </span>    74/jump-if-= <span class="Constant">break</span>/disp8
<span id="L513" class="LineNr"> 513 </span>    <span class="subxH1Comment"># - store al in keyboard buffer</span>
<span id="L514" class="LineNr"> 514 </span>    88/&lt;- *ecx 0/r32/al
<span id="L515" class="LineNr"> 515 </span>    <span class="subxComment"># increment index</span>
<span id="L516" class="LineNr"> 516 </span>    fe/increment-byte *<span class="SpecialChar">Keyboard-buffer</span>:<a href='108write.subx.html#L11'>write</a>
<span id="L517" class="LineNr"> 517 </span>    <span class="subxComment"># clear top nibble of index (keyboard buffer is circular)</span>
<span id="L518" class="LineNr"> 518 </span>    80 4/subop/and-byte *<span class="SpecialChar">Keyboard-buffer</span>:<a href='108write.subx.html#L11'>write</a> 0x0f/imm8
<span id="L519" class="LineNr"> 519 </span>  }
<span id="L520" class="LineNr"> 520 </span><span class="Constant">$keyboard-interrupt-handler:end</span>:
<span id="L521" class="LineNr"> 521 </span>  <span class="subxComment"># epilogue</span>
<span id="L522" class="LineNr"> 522 </span>  9d/pop-flags
<span id="L523" class="LineNr"> 523 </span>  61/pop-all-registers
<span id="L524" class="LineNr"> 524 </span>  fb/enable-interrupts
<span id="L525" class="LineNr"> 525 </span>  cf/return-from-interrupt
<span id="L526" class="LineNr"> 526 </span>
<span id="L527" class="LineNr"> 527 </span>== data
<span id="L528" class="LineNr"> 528 </span>Keyboard-shift-pressed?:  <span class="subxComment"># boolean</span>
<span id="L529" class="LineNr"> 529 </span>  0/imm32
<span id="L530" class="LineNr"> 530 </span>
<span id="L531" class="LineNr"> 531 </span>Keyboard-ctrl-pressed?:  <span class="subxComment"># boolean</span>
<span id="L532" class="LineNr"> 532 </span>  0/imm32
<span id="L533" class="LineNr"> 533 </span>
<span id="L534" class="LineNr"> 534 </span><span class="subxComment"># var keyboard circular buffer</span>
<span id="L535" class="LineNr"> 535 </span><span class="SpecialChar">Keyboard-buffer</span>:<a href='108write.subx.html#L11'>write</a>:  <span class="subxComment"># nibble</span>
<span id="L536" class="LineNr"> 536 </span>  0/imm32
<span id="L537" class="LineNr"> 537 </span><span class="SpecialChar">Keyboard-buffer</span>:read:  <span class="subxComment"># nibble</span>
<span id="L538" class="LineNr"> 538 </span>  0/imm32
<span id="L539" class="LineNr"> 539 </span><span class="SpecialChar">Keyboard-buffer</span>:data:  <span class="subxComment"># byte[16]</span>
<span id="L540" class="LineNr"> 540 </span>  00 00 00 00
<span id="L541" class="LineNr"> 541 </span>  00 00 00 00
<span id="L542" class="LineNr"> 542 </span>  00 00 00 00
<span id="L543" class="LineNr"> 543 </span>  00 00 00 00
<span id="L544" class="LineNr"> 544 </span>
<span id="L545" class="Folded"> 545 </span><span class="Folded">+-- 95 lines: # Keyboard maps for translating keys to ASCII ---------------------------------------------------------------------------------------------------------------------------</span>
<span id="L640" class="LineNr"> 640 </span>
<span id="L641" class="LineNr"> 641 </span><span class="SpecialChar">Video-mode-info</span>:
<span id="L642" class="Folded"> 642 </span><span class="Folded">+-- 53 lines: # video mode info -------------------------------------------------------------------------------------------------------------------------------------------------------</span>
<span id="L695" class="LineNr"> 695 </span>
<span id="L696" class="LineNr"> 696 </span><span class="subxComment">## Controlling IDE (ATA) hard disks</span>
<span id="L697" class="LineNr"> 697 </span><span class="subxComment"># Uses 28-bit PIO mode.</span>
<span id="L698" class="LineNr"> 698 </span><span class="subxComment"># Inspired by <a href="https://colorforth.github.io/ide.html">https://colorforth.github.io/ide.html</a></span>
<span id="L699" class="LineNr"> 699 </span><span class="subxComment">#</span>
<span id="L700" class="LineNr"> 700 </span><span class="subxComment"># Resources:</span>
<span id="L701" class="LineNr"> 701 </span><span class="subxComment">#   <a href="https://wiki.osdev.org/ATA_PIO_Mode">https://wiki.osdev.org/ATA_PIO_Mode</a></span>
<span id="L702" class="LineNr"> 702 </span><span class="subxComment">#   <a href="https://forum.osdev.org/viewtopic.php?f=1&amp;p=167798">https://forum.osdev.org/viewtopic.php?f=1&amp;p=167798</a></span>
<span id="L703" class="LineNr"> 703 </span><span class="subxComment">#   read-sector, according to <a href="https://www.scs.stanford.edu/11wi-cs140/pintos/specs/ata-3-std.pdf">https://www.scs.stanford.edu/11wi-cs140/pintos/specs/ata-3-std.pdf</a></span>
<span id="L704" class="LineNr"> 704 </span>
<span id="L705" class="LineNr"> 705 </span>== data
<span id="L706" class="LineNr"> 706 </span>
<span id="L707" class="LineNr"> 707 </span><span class="subxComment"># code disk</span>
<span id="L708" class="LineNr"> 708 </span><span class="subxComment"># All ports are 8-bit except data-port, which is 16-bit.</span>
<span id="L709" class="LineNr"> 709 </span><span class="SpecialChar">Primary-bus-primary-drive</span>:
<span id="L710" class="LineNr"> 710 </span>  <span class="subxComment"># command-port: int (write)</span>
<span id="L711" class="LineNr"> 711 </span>  0x1f7/imm32
<span id="L712" class="LineNr"> 712 </span>  <span class="subxComment"># status-port: int (read)</span>
<span id="L713" class="LineNr"> 713 </span>  0x1f7/imm32
<span id="L714" class="LineNr"> 714 </span>  <span class="subxComment"># alternative-status-port: int (read)</span>
<span id="L715" class="LineNr"> 715 </span>  0x3f6/imm32
<span id="L716" class="LineNr"> 716 </span>  <span class="subxComment"># error-port: int (read)</span>
<span id="L717" class="LineNr"> 717 </span>  0x1f1/imm32
<span id="L718" class="LineNr"> 718 </span>  <span class="subxComment"># drive-and-head-port: int</span>
<span id="L719" class="LineNr"> 719 </span>  0x1f6/imm32
<span id="L720" class="LineNr"> 720 </span>  <span class="subxComment"># sector-count-port: int</span>
<span id="L721" class="LineNr"> 721 </span>  0x1f2/imm32
<span id="L722" class="LineNr"> 722 </span>  <span class="subxComment"># lba-low-port: int</span>
<span id="L723" class="LineNr"> 723 </span>  0x1f3/imm32
<span id="L724" class="LineNr"> 724 </span>  <span class="subxComment"># lba-mid-port: int</span>
<span id="L725" class="LineNr"> 725 </span>  0x1f4/imm32
<span id="L726" class="LineNr"> 726 </span>  <span class="subxComment"># lba-high-port: int</span>
<span id="L727" class="LineNr"> 727 </span>  0x1f5/imm32
<span id="L728" class="LineNr"> 728 </span>  <span class="subxComment"># data-port: int</span>
<span id="L729" class="LineNr"> 729 </span>  0x1f0/imm32
<span id="L730" class="LineNr"> 730 </span>  <span class="subxComment"># drive-code: byte                # only drive-specific field</span>
<span id="L731" class="LineNr"> 731 </span>  0xe0/imm32  <span class="subxComment"># LBA mode also enabled</span>
<span id="L732" class="LineNr"> 732 </span>
<span id="L733" class="LineNr"> 733 </span><span class="subxComment"># data disk</span>
<span id="L734" class="LineNr"> 734 </span><span class="subxComment"># All ports are 8-bit except data-port, which is 16-bit.</span>
<span id="L735" class="LineNr"> 735 </span><span class="SpecialChar">Primary-bus-secondary-drive</span>:
<span id="L736" class="LineNr"> 736 </span>  <span class="subxComment"># command-port: int (write)</span>
<span id="L737" class="LineNr"> 737 </span>  0x1f7/imm32
<span id="L738" class="LineNr"> 738 </span>  <span class="subxComment"># status-port: int (read)</span>
<span id="L739" class="LineNr"> 739 </span>  0x1f7/imm32
<span id="L740" class="LineNr"> 740 </span>  <span class="subxComment"># alternative-status-port: int (read)</span>
<span id="L741" class="LineNr"> 741 </span>  0x3f6/imm32
<span id="L742" class="LineNr"> 742 </span>  <span class="subxComment"># error-port: int (read)</span>
<span id="L743" class="LineNr"> 743 </span>  0x1f1/imm32
<span id="L744" class="LineNr"> 744 </span>  <span class="subxComment"># drive-and-head-port: int</span>
<span id="L745" class="LineNr"> 745 </span>  0x1f6/imm32
<span id="L746" class="LineNr"> 746 </span>  <span class="subxComment"># sector-count-port: int</span>
<span id="L747" class="LineNr"> 747 </span>  0x1f2/imm32
<span id="L748" class="LineNr"> 748 </span>  <span class="subxComment"># lba-low-port: int</span>
<span id="L749" class="LineNr"> 749 </span>  0x1f3/imm32
<span id="L750" class="LineNr"> 750 </span>  <span class="subxComment"># lba-mid-port: int</span>
<span id="L751" class="LineNr"> 751 </span>  0x1f4/imm32
<span id="L752" class="LineNr"> 752 </span>  <span class="subxComment"># lba-high-port: int</span>
<span id="L753" class="LineNr"> 753 </span>  0x1f5/imm32
<span id="L754" class="LineNr"> 754 </span>  <span class="subxComment"># data-port: int</span>
<span id="L755" class="LineNr"> 755 </span>  0x1f0/imm32
<span id="L756" class="LineNr"> 756 </span>  <span class="subxComment"># drive-code: byte                # only drive-specific field</span>
<span id="L757" class="LineNr"> 757 </span>  0xf0/imm32  <span class="subxComment"># LBA mode also enabled</span>
<span id="L758" class="LineNr"> 758 </span>
<span id="L759" class="LineNr"> 759 </span>== code
<span id="L760" class="LineNr"> 760 </span>
<span id="L761" class="LineNr"> 761 </span><span class="subxComment"># No more than 0x100 sectors</span>
<span id="L762" class="LineNr"> 762 </span><span class="subxFunction">read-ata-disk</span>:  <span class="subxComment"># disk: (addr disk), lba: int, n: int, out: (addr stream byte)</span>
<span id="L763" class="LineNr"> 763 </span>  <span class="subxS1Comment"># . prologue</span>
<span id="L764" class="LineNr"> 764 </span>  55/push-ebp
<span id="L765" class="LineNr"> 765 </span>  89/&lt;- %ebp 4/r32/esp
<span id="L766" class="LineNr"> 766 </span>  <span class="subxS1Comment"># . save registers</span>
<span id="L767" class="LineNr"> 767 </span>  50/push-eax
<span id="L768" class="LineNr"> 768 </span>  51/push-ecx
<span id="L769" class="LineNr"> 769 </span>  52/push-edx
<span id="L770" class="LineNr"> 770 </span>  <span class="subxComment"># check precondition</span>
<span id="L771" class="LineNr"> 771 </span>  81 7/subop/compare *(ebp+0x10) 0x100/imm32
<span id="L772" class="LineNr"> 772 </span>  {
<span id="L773" class="LineNr"> 773 </span>    7e/jump-if-&lt;= <span class="Constant">break</span>/disp8
<span id="L774" class="LineNr"> 774 </span>    (<a href='317abort.subx.html#L5'>abort</a> <span class="Constant">&quot;read-ata-disk: no more than 0x100 sectors&quot;</span>)
<span id="L775" class="LineNr"> 775 </span>  }
<span id="L776" class="LineNr"> 776 </span>  <span class="subxComment"># check for drive</span>
<span id="L777" class="LineNr"> 777 </span>  (<a href='boot.subx.html#L940'>drive-exists?</a> *(ebp+8))  <span class="subxComment"># =&gt; eax</span>
<span id="L778" class="LineNr"> 778 </span>  3d/compare-eax-and 0/imm32/false
<span id="L779" class="LineNr"> 779 </span>  0f 84/jump-if-= $read-ata-disk:end/disp32
<span id="L780" class="LineNr"> 780 </span>  <span class="subxComment"># kick off read</span>
<span id="L781" class="LineNr"> 781 </span>  (<a href='boot.subx.html#L1004'>ata-drive-select</a> *(ebp+8) *(ebp+0xc))
<span id="L782" class="LineNr"> 782 </span>  (<a href='boot.subx.html#L1033'>clear-ata-error</a> *(ebp+8))
<span id="L783" class="LineNr"> 783 </span>  (<a href='boot.subx.html#L1055'>ata-sector-count</a> *(ebp+8) *(ebp+0x10))
<span id="L784" class="LineNr"> 784 </span>  (<a href='boot.subx.html#L1077'>ata-lba</a> *(ebp+8) *(ebp+0xc))
<span id="L785" class="LineNr"> 785 </span>  (<a href='boot.subx.html#L1108'>ata-command</a> *(ebp+8) 0x20)  <span class="subxComment"># read sectors with retries</span>
<span id="L786" class="LineNr"> 786 </span>  <span class="subxComment"># for each sector</span>
<span id="L787" class="LineNr"> 787 </span>  {
<span id="L788" class="LineNr"> 788 </span>    <span class="subxComment"># poll for results</span>
<span id="L789" class="LineNr"> 789 </span><span class="CommentedCode">#?     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;waiting for sector..&quot; 7 0)</span>
<span id="L790" class="LineNr"> 790 </span><span class="CommentedCode">#?     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;.&quot; 7 0)</span>
<span id="L791" class="LineNr"> 791 </span>    (<a href='boot.subx.html#L1130'>while-ata-busy</a> *(ebp+8))
<span id="L792" class="LineNr"> 792 </span>    (<a href='boot.subx.html#L1149'>until-ata-data-available</a> *(ebp+8))
<span id="L793" class="LineNr"> 793 </span><span class="CommentedCode">#?     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;reading\n&quot; 7 0)</span>
<span id="L794" class="LineNr"> 794 </span>    <span class="subxComment"># var data-port/edx = disk-&gt;data-port</span>
<span id="L795" class="LineNr"> 795 </span>    8b/-&gt; *(ebp+8) 0/r32/eax
<span id="L796" class="LineNr"> 796 </span>    8b/-&gt; *(eax+0x24) 2/r32/edx
<span id="L797" class="LineNr"> 797 </span>    <span class="subxComment"># emit results</span>
<span id="L798" class="LineNr"> 798 </span>    31/xor %eax 0/r32/eax
<span id="L799" class="LineNr"> 799 </span>    b9/copy-to-ecx 0x200/imm32  <span class="subxComment"># 512 bytes per sector</span>
<span id="L800" class="LineNr"> 800 </span>    {
<span id="L801" class="LineNr"> 801 </span>      81 7/subop/compare %ecx 0/imm32
<span id="L802" class="LineNr"> 802 </span>      74/jump-if-= <span class="Constant">break</span>/disp8
<span id="L803" class="LineNr"> 803 </span>      66 ed/read-port-dx-into-ax
<span id="L804" class="LineNr"> 804 </span>      <span class="subxComment"># write 2 bytes to stream one at a time</span>
<span id="L805" class="LineNr"> 805 </span>      (<a href='115write-byte.subx.html#L12'>append-byte</a> *(ebp+0x14) %eax)
<span id="L806" class="LineNr"> 806 </span>      49/decrement-ecx
<span id="L807" class="LineNr"> 807 </span>      c1/shift 5/subop/right-padding-zeroes %eax 8/imm8
<span id="L808" class="LineNr"> 808 </span>      (<a href='115write-byte.subx.html#L12'>append-byte</a> *(ebp+0x14) %eax)
<span id="L809" class="LineNr"> 809 </span>      49/decrement-ecx
<span id="L810" class="LineNr"> 810 </span>      eb/jump <span class="Constant">loop</span>/disp8
<span id="L811" class="LineNr"> 811 </span>    }
<span id="L812" class="LineNr"> 812 </span>    <span class="subxComment"># next sector</span>
<span id="L813" class="LineNr"> 813 </span>    ff 1/subop/decrement *(ebp+0x10)
<span id="L814" class="LineNr"> 814 </span><span class="CommentedCode">#?     (draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0 *(ebp+0x10) 0xc 0)</span>
<span id="L815" class="LineNr"> 815 </span>    81 7/subop/compare *(ebp+0x10) 0/imm32
<span id="L816" class="LineNr"> 816 </span>    7e/jump-if-&lt;= <span class="Constant">break</span>/disp8
<span id="L817" class="LineNr"> 817 </span>    (<a href='boot.subx.html#L1173'>wait-400ns</a> *(ebp+8))
<span id="L818" class="LineNr"> 818 </span><span class="CommentedCode">#?     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;next sector\n&quot; 7 0)</span>
<span id="L819" class="LineNr"> 819 </span>    e9/jump <span class="Constant">loop</span>/disp32
<span id="L820" class="LineNr"> 820 </span>  }
<span id="L821" class="LineNr"> 821 </span><span class="Constant">$read-ata-disk:end</span>:
<span id="L822" class="LineNr"> 822 </span>  <span class="subxS1Comment"># . restore registers</span>
<span id="L823" class="LineNr"> 823 </span>  5a/pop-to-edx
<span id="L824" class="LineNr"> 824 </span>  59/pop-to-ecx
<span id="L825" class="LineNr"> 825 </span>  58/pop-to-eax
<span id="L826" class="LineNr"> 826 </span>  <span class="subxS1Comment"># . epilogue</span>
<span id="L827" class="LineNr"> 827 </span>  89/&lt;- %esp 5/r32/ebp
<span id="L828" class="LineNr"> 828 </span>  5d/pop-to-ebp
<span id="L829" class="LineNr"> 829 </span>  c3/return
<span id="L830" class="LineNr"> 830 </span>
<span id="L831" class="LineNr"> 831 </span><span class="subxFunction">write-ata-disk</span>:  <span class="subxComment"># disk: (addr disk), lba: int, n: int, in: (addr stream byte)</span>
<span id="L832" class="LineNr"> 832 </span>  <span class="subxS1Comment"># . prologue</span>
<span id="L833" class="LineNr"> 833 </span>  55/push-ebp
<span id="L834" class="LineNr"> 834 </span>  89/&lt;- %ebp 4/r32/esp
<span id="L835" class="LineNr"> 835 </span>  <span class="subxS1Comment"># . save registers</span>
<span id="L836" class="LineNr"> 836 </span>  50/push-eax
<span id="L837" class="LineNr"> 837 </span>  51/push-ecx
<span id="L838" class="LineNr"> 838 </span>  52/push-edx
<span id="L839" class="LineNr"> 839 </span>  53/push-ebx
<span id="L840" class="LineNr"> 840 </span>  <span class="subxComment"># check for drive</span>
<span id="L841" class="LineNr"> 841 </span>  (<a href='boot.subx.html#L940'>drive-exists?</a> *(ebp+8))  <span class="subxComment"># =&gt; eax</span>
<span id="L842" class="LineNr"> 842 </span>  3d/compare-eax-and 0/imm32/false
<span id="L843" class="LineNr"> 843 </span>  0f 84/jump-if-= $write-ata-disk:end/disp32
<span id="L844" class="LineNr"> 844 </span>  <span class="subxComment"># kick off write</span>
<span id="L845" class="LineNr"> 845 </span>  (<a href='boot.subx.html#L1004'>ata-drive-select</a> *(ebp+8) *(ebp+0xc))
<span id="L846" class="LineNr"> 846 </span>  (<a href='boot.subx.html#L1033'>clear-ata-error</a> *(ebp+8))
<span id="L847" class="LineNr"> 847 </span>  (<a href='boot.subx.html#L1055'>ata-sector-count</a> *(ebp+8) *(ebp+0x10))
<span id="L848" class="LineNr"> 848 </span>  (<a href='boot.subx.html#L1077'>ata-lba</a> *(ebp+8) *(ebp+0xc))
<span id="L849" class="LineNr"> 849 </span>  (<a href='boot.subx.html#L1108'>ata-command</a> *(ebp+8) 0x30)  <span class="subxComment"># write sectors with retries</span>
<span id="L850" class="LineNr"> 850 </span>  <span class="subxComment"># for each sector</span>
<span id="L851" class="LineNr"> 851 </span><span class="CommentedCode">#?   (set-cursor-position 0 0 0)</span>
<span id="L852" class="LineNr"> 852 </span><span class="CommentedCode">#?   (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;0&quot; 7 0)</span>
<span id="L853" class="LineNr"> 853 </span>  {
<span id="L854" class="LineNr"> 854 </span>    <span class="subxComment"># wait</span>
<span id="L855" class="LineNr"> 855 </span>    (<a href='boot.subx.html#L1130'>while-ata-busy</a> *(ebp+8))
<span id="L856" class="LineNr"> 856 </span>    (<a href='boot.subx.html#L1168'>until-ata-ready-for-data</a> *(ebp+8))
<span id="L857" class="LineNr"> 857 </span>    <span class="subxComment"># var data-port/edx = disk-&gt;data-port</span>
<span id="L858" class="LineNr"> 858 </span>    8b/-&gt; *(ebp+8) 0/r32/eax
<span id="L859" class="LineNr"> 859 </span>    8b/-&gt; *(eax+0x24) 2/r32/edx
<span id="L860" class="LineNr"> 860 </span>    <span class="subxComment"># send data</span>
<span id="L861" class="LineNr"> 861 </span>    b9/copy-to-ecx 0x200/imm32  <span class="subxComment"># 512 bytes per sector</span>
<span id="L862" class="LineNr"> 862 </span>    <span class="subxS1Comment"># . var first-byte/ebx: byte</span>
<span id="L863" class="LineNr"> 863 </span>    <span class="subxS1Comment"># . when it's more than 0xff, we're at an even-numbered byte</span>
<span id="L864" class="LineNr"> 864 </span>    bb/copy-to-ebx 0xffff/imm32
<span id="L865" class="LineNr"> 865 </span><span class="CommentedCode">#?     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;D&quot; 7 0)</span>
<span id="L866" class="LineNr"> 866 </span><span class="Constant">$write-ata-disk:store-sector</span>:
<span id="L867" class="LineNr"> 867 </span>    {
<span id="L868" class="LineNr"> 868 </span>      81 7/subop/compare %ecx 0/imm32
<span id="L869" class="LineNr"> 869 </span>      74/jump-if-= <span class="Constant">break</span>/disp8
<span id="L870" class="LineNr"> 870 </span>      <span class="subxComment"># this loop is slow, but the ATA spec also requires a small delay</span>
<span id="L871" class="LineNr"> 871 </span>      (<a href='309stream.subx.html#L6'>stream-empty?</a> *(ebp+0x14))  <span class="subxComment"># =&gt; eax</span>
<span id="L872" class="LineNr"> 872 </span>      3d/compare-eax-and 0/imm32/false
<span id="L873" class="LineNr"> 873 </span>      75/jump-if-!= <span class="Constant">break</span>/disp8
<span id="L874" class="LineNr"> 874 </span>      <span class="subxComment"># read byte from stream</span>
<span id="L875" class="LineNr"> 875 </span>      (<a href='112read-byte.subx.html#L13'>read-byte</a> *(ebp+0x14))  <span class="subxComment"># =&gt; eax</span>
<span id="L876" class="LineNr"> 876 </span>      <span class="subxComment"># if we're at an odd-numbered byte, save it to first-byte</span>
<span id="L877" class="LineNr"> 877 </span>      81 7/subop/compare %ebx 0xff/imm32
<span id="L878" class="LineNr"> 878 </span>      {
<span id="L879" class="LineNr"> 879 </span>        7e/jump-if-&lt;= <span class="Constant">break</span>/disp8
<span id="L880" class="LineNr"> 880 </span>        89/&lt;- %ebx 0/r32/eax
<span id="L881" class="LineNr"> 881 </span>        eb/jump $write-ata-disk:store-sector/disp8
<span id="L882" class="LineNr"> 882 </span>      }
<span id="L883" class="LineNr"> 883 </span>      <span class="subxComment"># otherwise OR it with first-byte and write it out</span>
<span id="L884" class="LineNr"> 884 </span>      c1/shift 4/subop/left %eax 8/imm8
<span id="L885" class="LineNr"> 885 </span>      09/or %eax 3/r32/ebx
<span id="L886" class="LineNr"> 886 </span>      66 ef/write-ax-into-port-dx
<span id="L887" class="LineNr"> 887 </span>      49/decrement-ecx
<span id="L888" class="LineNr"> 888 </span>      49/decrement-ecx
<span id="L889" class="LineNr"> 889 </span>      <span class="subxComment"># reset first-byte</span>
<span id="L890" class="LineNr"> 890 </span>      bb/copy-to-ebx 0xffff/imm32
<span id="L891" class="LineNr"> 891 </span>      eb/jump <span class="Constant">loop</span>/disp8
<span id="L892" class="LineNr"> 892 </span>    }
<span id="L893" class="LineNr"> 893 </span>    <span class="subxComment"># write out final first-byte if necessary</span>
<span id="L894" class="LineNr"> 894 </span><span class="CommentedCode">#?     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;I&quot; 7 0)</span>
<span id="L895" class="LineNr"> 895 </span>    81 7/subop/compare %ebx 0xff/imm32
<span id="L896" class="LineNr"> 896 </span>    {
<span id="L897" class="LineNr"> 897 </span>      7f/jump-if-&gt; <span class="Constant">break</span>/disp8
<span id="L898" class="LineNr"> 898 </span>      89/&lt;- %eax 3/r32/ebx
<span id="L899" class="LineNr"> 899 </span>      66 ef/write-ax-into-port-dx
<span id="L900" class="LineNr"> 900 </span>      49/decrement-ecx
<span id="L901" class="LineNr"> 901 </span>      49/decrement-ecx
<span id="L902" class="LineNr"> 902 </span>    }
<span id="L903" class="LineNr"> 903 </span>    <span class="subxComment"># pad zeroes</span>
<span id="L904" class="LineNr"> 904 </span><span class="CommentedCode">#?     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;P&quot; 7 0)</span>
<span id="L905" class="LineNr"> 905 </span>    31/xor %eax 0/r32/eax
<span id="L906" class="LineNr"> 906 </span>    {
<span id="L907" class="LineNr"> 907 </span>      81 7/subop/compare %ecx 0/imm32
<span id="L908" class="LineNr"> 908 </span>      74/jump-if-= <span class="Constant">break</span>/disp8
<span id="L909" class="LineNr"> 909 </span>      66 ef/write-ax-into-port-dx
<span id="L910" class="LineNr"> 910 </span>      49/decrement-ecx
<span id="L911" class="LineNr"> 911 </span>      49/decrement-ecx
<span id="L912" class="LineNr"> 912 </span>      eb/jump <span class="Constant">loop</span>/disp8
<span id="L913" class="LineNr"> 913 </span>    }
<span id="L914" class="LineNr"> 914 </span>    <span class="subxComment"># next sector</span>
<span id="L915" class="LineNr"> 915 </span><span class="CommentedCode">#?     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;N&quot; 7 0)</span>
<span id="L916" class="LineNr"> 916 </span>    ff 1/subop/decrement *(ebp+0x10)
<span id="L917" class="LineNr"> 917 </span>    81 7/subop/compare *(ebp+0x10) 0/imm32
<span id="L918" class="LineNr"> 918 </span>    7e/jump-if-&lt;= <span class="Constant">break</span>/disp8
<span id="L919" class="LineNr"> 919 </span><span class="CommentedCode">#?     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;W&quot; 7 0)</span>
<span id="L920" class="LineNr"> 920 </span>    (<a href='boot.subx.html#L1173'>wait-400ns</a> *(ebp+8))
<span id="L921" class="LineNr"> 921 </span><span class="CommentedCode">#?     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;L&quot; 7 0)</span>
<span id="L922" class="LineNr"> 922 </span>    e9/jump <span class="Constant">loop</span>/disp32
<span id="L923" class="LineNr"> 923 </span>  }
<span id="L924" class="LineNr"> 924 </span><span class="CommentedCode">#?   (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;F&quot; 7 0)</span>
<span id="L925" class="LineNr"> 925 </span>  (<a href='boot.subx.html#L1207'>flush-ata-cache</a> *(ebp+8))
<span id="L926" class="LineNr"> 926 </span><span class="CommentedCode">#?   (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 &quot;Y&quot; 7 0)</span>
<span id="L927" class="LineNr"> 927 </span><span class="Constant">$write-ata-disk:end</span>:
<span id="L928" class="LineNr"> 928 </span>  <span class="subxS1Comment"># . restore registers</span>
<span id="L929" class="LineNr"> 929 </span>  5b/pop-to-ebx
<span id="L930" class="LineNr"> 930 </span>  5a/pop-to-edx
<span id="L931" class="LineNr"> 931 </span>  59/pop-to-ecx
<span id="L932" class="LineNr"> 932 </span>  58/pop-to-eax
<span id="L933" class="LineNr"> 933 </span>  <span class="subxS1Comment"># . epilogue</span>
<span id="L934" class="LineNr"> 934 </span>  89/&lt;- %esp 5/r32/ebp
<span id="L935" class="LineNr"> 935 </span>  5d/pop-to-ebp
<span id="L936" class="LineNr"> 936 </span>  c3/return
<span id="L937" class="LineNr"> 937 </span>
<span id="L938" class="Folded"> 938 </span><span class="Folded">+--289 lines: # disk helpers ----------------------------------------------------------------------------------------------------------------------------------------------------------</span>
<span id="L1227" class="LineNr">1227 </span>
<span id="L1228" class="LineNr">1228 </span><span class="subxComment">## Controlling a PS/2 mouse</span>
<span id="L1229" class="LineNr">1229 </span><span class="subxComment"># Uses no IRQs, just polling.</span>
<span id="L1230" class="LineNr">1230 </span><span class="subxComment"># Thanks Dave Long: <a href="https://github.com/jtauber/cleese/blob/master/necco/kernel/bochs/py8042.py">https://github.com/jtauber/cleese/blob/master/necco/kernel/bochs/py8042.py</a></span>
<span id="L1231" class="LineNr">1231 </span><span class="subxComment">#</span>
<span id="L1232" class="LineNr">1232 </span><span class="subxComment"># Resources:</span>
<span id="L1233" class="LineNr">1233 </span><span class="subxComment">#   <a href="https://wiki.osdev.org/Mouse_Input">https://wiki.osdev.org/Mouse_Input</a></span>
<span id="L1234" class="LineNr">1234 </span>
<span id="L1235" class="LineNr">1235 </span><span class="subxComment"># results x/eax, y/ecx range from -256 to +255</span>
<span id="L1236" class="LineNr">1236 </span><span class="subxComment"># See <a href="https://wiki.osdev.org/index.php?title=Mouse_Input&amp;oldid=25663#Format_of_First_3_Packet_Bytes">https://wiki.osdev.org/index.php?title=Mouse_Input&amp;oldid=25663#Format_of_First_3_Packet_Bytes</a></span>
<span id="L1237" class="LineNr">1237 </span><span class="subxFunction">read-mouse-event</span>:  <span class="subxComment"># -&gt; _/eax: int, _/ecx: int</span>
<span id="L1238" class="LineNr">1238 </span>  <span class="subxS1Comment"># . prologue</span>
<span id="L1239" class="LineNr">1239 </span>  55/push-ebp
<span id="L1240" class="LineNr">1240 </span>  89/&lt;- %ebp 4/r32/esp
<span id="L1241" class="LineNr">1241 </span>  <span class="subxS1Comment"># . save registers</span>
<span id="L1242" class="LineNr">1242 </span>  52/push-edx
<span id="L1243" class="LineNr">1243 </span>  53/push-ebx
<span id="L1244" class="LineNr">1244 </span>  <span class="subxComment"># if no event, return 0, 0</span>
<span id="L1245" class="LineNr">1245 </span>  b8/copy-to-eax 0/imm32
<span id="L1246" class="LineNr">1246 </span>  b9/copy-to-ecx 0/imm32
<span id="L1247" class="LineNr">1247 </span>  (<a href='boot.subx.html#L1304'>any-mouse-event?</a>)  <span class="subxComment"># =&gt; eax</span>
<span id="L1248" class="LineNr">1248 </span>  3d/compare-eax-and 0/imm32/false
<span id="L1249" class="LineNr">1249 </span>  74/jump-if-= $read-mouse-event:end/disp8
<span id="L1250" class="LineNr">1250 </span>  <span class="subxComment"># var f1/edx: byte = inb(0x60)</span>
<span id="L1251" class="LineNr">1251 </span>  31/xor %eax 0/r32/eax
<span id="L1252" class="LineNr">1252 </span>  e4/read-port-into-al 0x60/imm8
<span id="L1253" class="LineNr">1253 </span>  89/&lt;- %edx 0/r32/eax
<span id="L1254" class="LineNr">1254 </span>  (<a href='boot.subx.html#L1289'>wait-for-mouse-event</a>)
<span id="L1255" class="LineNr">1255 </span>  <span class="subxComment"># var dx/ebx: byte = inb(0x60)</span>
<span id="L1256" class="LineNr">1256 </span>  31/xor %eax 0/r32/eax
<span id="L1257" class="LineNr">1257 </span>  e4/read-port-into-al 0x60/imm8
<span id="L1258" class="LineNr">1258 </span>  89/&lt;- %ebx 0/r32/eax
<span id="L1259" class="LineNr">1259 </span>  (<a href='boot.subx.html#L1289'>wait-for-mouse-event</a>)
<span id="L1260" class="LineNr">1260 </span>  <span class="subxComment"># var dy/ecx: byte = inb(0x60)</span>
<span id="L1261" class="LineNr">1261 </span>  31/xor %eax 0/r32/eax
<span id="L1262" class="LineNr">1262 </span>  e4/read-port-into-al 0x60/imm8
<span id="L1263" class="LineNr">1263 </span>  89/&lt;- %ecx 0/r32/eax
<span id="L1264" class="LineNr">1264 </span>  <span class="subxComment"># eax = dx</span>
<span id="L1265" class="LineNr">1265 </span>  89/&lt;- %eax 3/r32/ebx
<span id="L1266" class="LineNr">1266 </span>  <span class="subxComment"># if (f1 &amp; 0x10) dx = -dx</span>
<span id="L1267" class="LineNr">1267 </span>  {
<span id="L1268" class="LineNr">1268 </span>    f6 0/subop/test-bits %dl 0x10/imm8
<span id="L1269" class="LineNr">1269 </span>    74/jump-if-zero <span class="Constant">break</span>/disp8
<span id="L1270" class="LineNr">1270 </span>    0d/or-eax-with 0xffffff00/imm32
<span id="L1271" class="LineNr">1271 </span>  }
<span id="L1272" class="LineNr">1272 </span>  <span class="subxComment"># if (f1 &amp; 0x20) dy = -dy</span>
<span id="L1273" class="LineNr">1273 </span>  {
<span id="L1274" class="LineNr">1274 </span>    f6 0/subop/test-bits %dl 0x20/imm8
<span id="L1275" class="LineNr">1275 </span>    74/jump-if-zero <span class="Constant">break</span>/disp8
<span id="L1276" class="LineNr">1276 </span>    81 1/subop/or %ecx 0xffffff00/imm32
<span id="L1277" class="LineNr">1277 </span>  }
<span id="L1278" class="LineNr">1278 </span><span class="Constant">$read-mouse-event:end</span>:
<span id="L1279" class="LineNr">1279 </span>  <span class="subxS1Comment"># . restore registers</span>
<span id="L1280" class="LineNr">1280 </span>  5b/pop-to-ebx
<span id="L1281" class="LineNr">1281 </span>  5a/pop-to-edx
<span id="L1282" class="LineNr">1282 </span>  <span class="subxS1Comment"># . epilogue</span>
<span id="L1283" class="LineNr">1283 </span>  89/&lt;- %esp 5/r32/ebp
<span id="L1284" class="LineNr">1284 </span>  5d/pop-to-ebp
<span id="L1285" class="LineNr">1285 </span>  c3/return
<span id="L1286" class="LineNr">1286 </span>
<span id="L1287" class="Folded">1287 </span><span class="Folded">+--147 lines: # mouse helpers ---------------------------------------------------------------------------------------------------------------------------------------------------------</span>
<span id="L1434" class="LineNr">1434 </span>
<span id="L1435" class="LineNr">1435 </span><span class="subxComment"># vim&#0058;ft=subx</span>
</pre>
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