mu - Soul of a tiny new machine. More thorough tests → More comprehensible and rewrite-friendly software → More resilient society.

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html/linux/125write-stream-data.subx.html

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# Code for the first few disk sectors that all programs in this directory need: # - load sectors past the first (using BIOS primitives) since only the first is available by default # - if this fails, print 'D' at top-left of screen and halt # - initialize a minimal graphics mode # - switch to 32-bit mode (giving up access to BIOS primitives) # - set up a handler for keyboard events # - jump to start of program # Code in this file needs to be more deliberate about the SubX facilities it # uses: # - sigils only support 32-bit general-purpose registers, so don't work with segment registers or 16-bit or 8-bit registers # - metadata like rm32 and r32 can sometimes misleadingly refer to only the bottom 16 bits of the register; pay attention to the register name # # While most of Mu is thoroughly tested, this file is not. I don't yet # understand hardware interfaces well enough to explain to others. # Memory map of a Mu computer: # code: [0x00007c00, 0x0007de00) # system font: [0x00100000, 0x00f00000) # stack: (0x02000000, 0x01000000] # heap: [0x02000000, 0x80000000) # see 120allocate.subx; Qemu initializes with 128MB RAM by default; simulating 2GB RAM is known to work # Consult https://wiki.osdev.org/Memory_Map_(x86) before modifying any of # this. And don't forget to keep *stack-debug.subx in sync. == code ## 16-bit entry point: 0x7c00 # Upon reset, the IBM PC: # - loads the first sector (512 bytes) # from some bootable image (look for the boot-sector-marker further down this file) # to the address range [0x7c00, 0x7e00) # - starts executing code at address 0x7c00 fa/disable-interrupts # initialize segment registers b8/copy-to-ax 0/imm16 8e/->seg 3/mod/direct 0/rm32/ax 3/r32/ds 8e/->seg 3/mod/direct 0/rm32/ax 0/r32/es 8e/->seg 3/mod/direct 0/rm32/ax 4/r32/fs 8e/->seg 3/mod/direct 0/rm32/ax 5/r32/gs # Temporarily initialize stack to 0x00070000 in real mode. # We don't read or write the stack before we get to 32-bit mode, but BIOS # calls do. We need to move the stack in case BIOS initializes it to some # low address that we want to write code into. b8/copy-to-ax 0x7000/imm16 8e/->seg 3/mod/direct 0/rm32/ax 2/r32/ss bc/copy-to-esp 0/imm16 # undo the A20 hack: https://en.wikipedia.org/wiki/A20_line # this is from https://github.com/mit-pdos/xv6-public/blob/master/bootasm.S { e4/read-port-into-al 0x64/imm8 a8/test-bits-in-al 0x02/imm8 # set zf if bit 1 (second-least significant) is not set 75/jump-if-!zero loop/disp8 b0/copy-to-al 0xd1/imm8 e6/write-al-into-port 0x64/imm8 } { e4/read-port-into-al 0x64/imm8 a8/test-bits-in-al 0x02/imm8 # set zf if bit 1 (second-least significant) is not set 75/jump-if-!zero loop/disp8 b0/copy-to-al 0xdf/imm8 e6/write-al-into-port 0x64/imm8 } # load remaining sectors from first two tracks of disk into addresses [0x7e00, 0x17800) b4/copy-to-ah 2/imm8/read-drive # dl comes conveniently initialized at boot time with the index of the device being booted b5/copy-to-ch 0/imm8/cylinder b6/copy-to-dh 0/imm8/head # <==== b1/copy-to-cl 2/imm8/sector # 1-based b0/copy-to-al 0x7d/imm8/num-sectors # 2*63 - 1 = 125 # address to write sectors to = es:bx = 0x7e00, contiguous with boot segment bb/copy-to-bx 0/imm16 8e/->seg 3/mod/direct 3/rm32/bx 0/r32/es bb/copy-to-bx 0x7e00/imm16 # <==== cd/syscall 0x13/imm8/bios-disk-services 0f 82/jump-if-carry disk_error/disp16 # load two more tracks of disk into addresses [0x17800, 0x27400) b4/copy-to-ah 2/imm8/read-drive # dl comes conveniently initialized at boot time with the index of the device being booted b5/copy-to-ch 0/imm8/cylinder b6/copy-to-dh 2/imm8/head # <==== b1/copy-to-cl 1/imm8/sector # 1-based b0/copy-to-al 0x7e/imm8/num-sectors # 2*63 = 126 # address to write sectors to = es:bx = 0x17800, contiguous with boot segment bb/copy-to-bx 0x1780/imm16 # <==== 8e/->seg 3/mod/direct 3/rm32/bx 0/r32/es bb/copy-to-bx 0/imm16 cd/syscall 0x13/imm8/bios-disk-services 0f 82/jump-if-carry disk_error/disp16 # load two more tracks of disk into addresses [0x27400, 0x37000) b4/copy-to-ah 2/imm8/read-drive # dl comes conveniently initialized at boot time with the index of the device being booted b5/copy-to-ch 0/imm8/cylinder b6/copy-to-dh 4/imm8/head # <==== b1/copy-to-cl 1/imm8/sector # 1-based b0/copy-to-al 0x7e/imm8/num-sectors # 2*63 = 126 # address to write sectors to = es:bx = 0x27400, contiguous with boot segment bb/copy-to-bx 0x2740/imm16 # <==== 8e/->seg 3/mod/direct 3/rm32/bx 0/r32/es bb/copy-to-bx 0/imm16 cd/syscall 0x13/imm8/bios-disk-services 0f 82/jump-if-carry disk_error/disp16 # load two more tracks of disk into addresses [0x37000, 0x46c00) b4/copy-to-ah 2/imm8/read-drive # dl comes conveniently initialized at boot time with the index of the device being booted b5/copy-to-ch 0/imm8/cylinder b6/copy-to-dh 6/imm8/head # <==== b1/copy-to-cl 1/imm8/sector # 1-based b0/copy-to-al 0x7e/imm8/num-sectors # 2*63 = 126 # address to write sectors to = es:bx = 0x37000, contiguous with boot segment bb/copy-to-bx 0x3700/imm16 # <==== 8e/->seg 3/mod/direct 3/rm32/bx 0/r32/es bb/copy-to-bx 0/imm16 cd/syscall 0x13/imm8/bios-disk-services 0f 82/jump-if-carry disk_error/disp16 # load two more tracks of disk into addresses [0x46c00, 0x56800) b4/copy-to-ah 2/imm8/read-drive # dl comes conveniently initialized at boot time with the index of the device being booted b5/copy-to-ch 0/imm8/cylinder b6/copy-to-dh 8/imm8/head # <==== b1/copy-to-cl 1/imm8/sector # 1-based b0/copy-to-al 0x7e/imm8/num-sectors # 2*63 = 126 # address to write sectors to = es:bx = 0x46c00, contiguous with boot segment bb/copy-to-bx 0x46c0/imm16 # <==== 8e/->seg 3/mod/direct 3/rm32/bx 0/r32/es bb/copy-to-bx 0/imm16 cd/syscall 0x13/imm8/bios-disk-services 0f 82/jump-if-carry disk_error/disp16 # load two more tracks of disk into addresses [0x56800, 0x66400) b4/copy-to-ah 2/imm8/read-drive # dl comes conveniently initialized at boot time with the index of the device being booted b5/copy-to-ch 0/imm8/cylinder b6/copy-to-dh 0xa/imm8/head # <==== b1/copy-to-cl 1/imm8/sector # 1-based b0/copy-to-al 0x7e/imm8/num-sectors # 2*63 = 126 # address to write sectors to = es:bx = 0x56800, contiguous with boot segment bb/copy-to-bx 0x5680/imm16 # <==== 8e/->seg 3/mod/direct 3/rm32/bx 0/r32/es bb/copy-to-bx 0/imm16 cd/syscall 0x13/imm8/bios-disk-services 0f 82/jump-if-carry disk_error/disp16 # load two more tracks of disk into addresses [0x66400, 0x76000) b4/copy-to-ah 2/imm8/read-drive # dl comes conveniently initialized at boot time with the index of the device being booted b5/copy-to-ch 0/imm8/cylinder b6/copy-to-dh 0xc/imm8/head # <==== b1/copy-to-cl 1/imm8/sector # 1-based b0/copy-to-al 0x7e/imm8/num-sectors # 2*63 = 126 # address to write sectors to = es:bx = 0x56800, contiguous with boot segment bb/copy-to-bx 0x6640/imm16 # <==== 8e/->seg 3/mod/direct 3/rm32/bx 0/r32/es bb/copy-to-bx 0/imm16 cd/syscall 0x13/imm8/bios-disk-services 0f 82/jump-if-carry disk_error/disp16 # load one final track of disk into addresses [0x76000, 0x7de00) b4/copy-to-ah 2/imm8/read-drive # dl comes conveniently initialized at boot time with the index of the device being booted b5/copy-to-ch 0/imm8/cylinder b6/copy-to-dh 0xe/imm8/head # <==== b1/copy-to-cl 1/imm8/sector # 1-based b0/copy-to-al 0x3f/imm8/num-sectors=63 # address to write sectors to = es:bx = 0x56800, contiguous with boot segment bb/copy-to-bx 0x7600/imm16 # <==== 8e/->seg 3/mod/direct 3/rm32/bx 0/r32/es bb/copy-to-bx 0/imm16 cd/syscall 0x13/imm8/bios-disk-services 0f 82/jump-if-carry disk_error/disp16 ### Loading more code tracks would clobber BIOS; we need a new compilation strategy. # reset es bb/copy-to-bx 0/imm16 8e/->seg 3/mod/direct 3/rm32/bx 0/r32/es # adjust video mode b4/copy-to-ah 0x4f/imm8 # VBE commands b0/copy-to-al 2/imm8 # set video mode bb/copy-to-bx 0x4105/imm16 # 0x0105 | 0x4000 # 0x0105 = graphics mode 1024x768x256 # (alternative candidate: 0x0101 for 640x480x256) # 0x4000 bit = configure linear frame buffer in Bochs emulator; hopefully this doesn't hurt anything when running natively cd/syscall 0x10/imm8/bios-video-services # load information for the (hopefully) current video mode # mostly just for the address to the linear frame buffer b4/copy-to-ah 0x4f/imm8 # VBE commands b0/copy-to-al 1/imm8 # get video mode info b9/copy-to-cx 0x0105/imm16 # mode we requested bf/copy-to-di Video-mode-info/imm16 cd/syscall 0x10/imm8/bios-video-services ## switch to 32-bit mode # load global descriptor table # We can't refer to the label directly because SubX doesn't do the right # thing for lgdt, so rather than make errors worse in most places we instead # pin gdt_descriptor below. 0f 01 2/subop/lgdt 0/mod/indirect 6/rm32/use-disp16 0x7de0/disp16/gdt_descriptor # enable paging 0f 20/<-cr 3/mod/direct 0/rm32/eax 0/r32/cr0 66 83 1/subop/or 3/mod/direct 0/rm32/eax 1/imm8 # eax <- or 0x1 0f 22/->cr 3/mod/direct 0/rm32/eax 0/r32/cr0 # far jump to initialize_32bit_mode that sets cs to offset 8 in the gdt in the process # We can't refer to the label directly because SubX doesn't have syntax for # segment selectors. So we instead pin initialize_32bit_mode below. ea/jump-far-absolute 0x00087e00/disp32 # address 0x7e00 in offset 8 of the gdt disk_error: # print 'D' to top-left of screen to indicate disk error # *0xb8000 <- 0x0f44 bb/copy-to-bx 0xb800/imm16 8e/->seg 3/mod/direct 3/rm32/bx 3/r32/ds b0/copy-to-al 0x44/imm8/D b4/copy-to-ah 0x0f/imm8/white-on-black bb/copy-to-bx 0/imm16 89/<- 0/mod/indirect 7/rm32/bx 0/r32/ax # *ds:bx <- ax # loop forever { eb/jump loop/disp8 } ## GDT: 3 records of 8 bytes each == data 0x7de0 gdt_descriptor: 0x17/imm16 # final index of gdt = size of gdt - 1 gdt_start/imm32/start gdt_start: # offset 0: gdt_null: mandatory null descriptor 00 00 00 00 00 00 00 00 # offset 8: gdt_code ff ff # limit[0:16] 00 00 00 # base[0:24] 9a # 1/present 00/privilege 1/descriptor type = 1001b # 1/code 0/conforming 1/readable 0/accessed = 1010b cf # 1/granularity 1/32-bit 0/64-bit-segment 0/AVL = 1100b # limit[16:20] = 1111b 00 # base[24:32] # offset 16: gdt_data ff ff # limit[0:16] 00 00 00 # base[0:24] 92 # 1/present 00/privilege 1/descriptor type = 1001b # 0/data 0/conforming 1/readable 0/accessed = 0010b cf # same as gdt_code 00 # base[24:32] # gdt_end: == boot-sector-marker 0x7dfe # final 2 bytes of boot sector 55 aa ## sector 2 onwards loaded by load_disk, not automatically on boot ## 32-bit code from this point == code 0x7e00 initialize_32bit_mode: 66 b8/copy-to-ax 0x10/imm16 # offset 16 from gdt_start 8e/->seg 3/mod/direct 0/rm32/ax 3/r32/ds 8e/->seg 3/mod/direct 0/rm32/ax 2/r32/ss 8e/->seg 3/mod/direct 0/rm32/ax 0/r32/es 8e/->seg 3/mod/direct 0/rm32/ax 4/r32/fs 8e/->seg 3/mod/direct 0/rm32/ax 5/r32/gs bc/copy-to-esp 0x02000000/imm32 ## install the font somewhere non-contiguous (keep sync'd with memory map up top) c7 0/subop/copy *0x00100000 0/imm32/read c7 0/subop/copy *0x00100004 0/imm32/write c7 0/subop/copy *0x00100008 0x00e00000/imm32/size (load-sectors Primary-bus-primary-drive 0x2328 0x200 0x00100000) # source 0x2328 = sector 9000 on disk, destination 0x00100000 # Font is now loaded starting at 0x0010000c. ## load interrupt handlers # We can't refer to the label directly because SubX doesn't do the right # thing for lidt, so rather than make errors worse in most places we instead # pin idt_descriptor below. 0f 01 3/subop/lidt 0/mod/indirect 5/rm32/use-disp32 0x7f00/disp32/idt_descriptor # For now, not bothering reprogramming the IRQ to not conflict with software # exceptions. # https://wiki.osdev.org/index.php?title=8259_PIC&oldid=24650#Protected_Mode # # Interrupt 1 (keyboard) conflicts with debugger faults. We don't use a # debugger. # Reference: # https://wiki.osdev.org/Exceptions # enable timer IRQ0 and keyboard IRQ1 b0/copy-to-al 0xfc/imm8 # disable mask for IRQ0 and IRQ1 e6/write-al-into-port 0x21/imm8 fb/enable-interrupts (initialize-mouse) ## enable floating point db/floating-point-coprocessor e3/initialize # eax <- cr4 0f 20/<-cr 3/mod/direct 0/rm32/eax 4/r32/cr4 # eax <- or bit 9 0f ba/bit-test 5/subop/bit-test-and-set 3/mod/direct 0/rm32/eax 9/imm8 # cr4 <- eax 0f 22/->cr 3/mod/direct 0/rm32/eax 4/r32/cr4 e9/jump Entry/disp32 == data 0x7f00 idt_descriptor: ff 03 # final index of idt = size of idt - 1 idt_start/imm32/start # interrupt descriptor table {{{ # 32 entries of 8 bytes each idt_start: # entry 0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 # By default, BIOS maps IRQ0-7 to interrupt vectors 8-15. # https://wiki.osdev.org/index.php?title=Interrupts&oldid=25102#Default_PC_Interrupt_Vector_Assignment # entry 8: https://wiki.osdev.org/Programmable_Interval_Timer timer-interrupt-handler/imm16 # target[0:16] 8/imm16 # segment selector (gdt_code) 00 # unused 8e # 1/p 00/dpl 0 1110/type/32-bit-interrupt-gate 0/imm16 # target[16:32] -- timer-interrupt-handler must be within address 0x10000 # entry 9: keyboard keyboard-interrupt-handler/imm16 # target[0:16] 8/imm16 # segment selector (gdt_code) 00 # unused 8e # 1/p 00/dpl 0 1110/type/32-bit-interrupt-gate 0/imm16 # target[16:32] -- keyboard-interrupt-handler must be within address 0x10000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 # idt_end: # }}} == code timer-interrupt-handler: # prologue fa/disable-interrupts 60/push-all-registers 9c/push-flags # acknowledge interrupt b0/copy-to-al 0x20/imm8 e6/write-al-into-port 0x20/imm8 31/xor %eax 0/r32/eax # update *Timer-current-color ff 0/subop/increment *Timer-counter $timer-interrupt-handler:epilogue: # epilogue 9d/pop-flags 61/pop-all-registers fb/enable-interrupts cf/return-from-interrupt == data Timer-counter: 0/imm32 == code keyboard-interrupt-handler: # prologue fa/disable-interrupts 60/push-all-registers 9c/push-flags # acknowledge interrupt b0/copy-to-al 0x20/imm8 e6/write-al-into-port 0x20/imm8 31/xor %eax 0/r32/eax # check output buffer of 8042 keyboard controller (https://web.archive.org/web/20040604041507/http://panda.cs.ndsu.nodak.edu/~achapwes/PICmicro/keyboard/atkeyboard.html) e4/read-port-into-al 0x64/imm8 a8/test-bits-in-al 0x01/imm8 # set zf if bit 0 (least significant) is not set 0f 84/jump-if-not-set $keyboard-interrupt-handler:end/disp32 # - if keyboard buffer is full, return # var dest-addr/ecx: (addr byte) = (keyboard-buffer + *keyboard-buffer:write) 31/xor %ecx 1/r32/ecx 8a/byte-> *Keyboard-buffer:write 1/r32/cl 81 0/subop/add %ecx Keyboard-buffer:data/imm32 # al = *dest-addr 8a/byte-> *ecx 0/r32/al # if (al != 0) return 3c/compare-al-and 0/imm8 0f 85/jump-if-!= $keyboard-interrupt-handler:end/disp32 # - read keycode e4/read-port-into-al 0x60/imm8 # - key released # if (al == 0xaa) shift = false # left shift is being lifted { 3c/compare-al-and 0xaa/imm8 75/jump-if-!= break/disp8 # *shift = 0 c7 0/subop/copy *Keyboard-shift-pressed? 0/imm32 } # if (al == 0xb6) shift = false # right shift is being lifted { 3c/compare-al-and 0xb6/imm8 75/jump-if-!= break/disp8 # *shift = 0 c7 0/subop/copy *Keyboard-shift-pressed? 0/imm32 } # if (al == 0x9d) ctrl = false # ctrl is being lifted { 3c/compare-al-and 0x9d/imm8 75/jump-if-!= break/disp8 # *ctrl = 0 c7 0/subop/copy *Keyboard-ctrl-pressed? 0/imm32 } # if (al & 0x80) a key is being lifted; return 50/push-eax 24/and-al-with 0x80/imm8 3c/compare-al-and 0/imm8 58/pop-to-eax 75/jump-if-!= $keyboard-interrupt-handler:end/disp8 # - key pressed # if (al == 0x2a) shift = true, return # left shift pressed { 3c/compare-al-and 0x2a/imm8 75/jump-if-!= break/disp8 # *shift = 1 c7 0/subop/copy *Keyboard-shift-pressed? 1/imm32 # return eb/jump $keyboard-interrupt-handler:end/disp8 } # if (al == 0x36) shift = true, return # right shift pressed { 3c/compare-al-and 0x36/imm8 75/jump-if-!= break/disp8 # *shift = 1 c7 0/subop/copy *Keyboard-shift-pressed? 1/imm32 # return eb/jump $keyboard-interrupt-handler:end/disp8 } # if (al == 0x1d) ctrl = true, return { 3c/compare-al-and 0x1d/imm8 75/jump-if-!= break/disp8 # *ctrl = 1 c7 0/subop/copy *Keyboard-ctrl-pressed? 1/imm32 # return eb/jump $keyboard-interrupt-handler:end/disp8 } # - convert key to character # if (shift) use keyboard shift map { 81 7/subop/compare *Keyboard-shift-pressed? 0/imm32 74/jump-if-= break/disp8 # sigils don't currently support labels inside *(eax+label) 05/add-to-eax Keyboard-shift-map/imm32 8a/byte-> *eax 0/r32/al eb/jump $keyboard-interrupt-handler:select-map-done/disp8 } # if (ctrl) al = *(ctrl map + al) { 81 7/subop/compare *Keyboard-ctrl-pressed? 0/imm32 74/jump-if-= break/disp8 05/add-to-eax Keyboard-ctrl-map/imm32 8a/byte-> *eax 0/r32/al eb/jump $keyboard-interrupt-handler:select-map-done/disp8 } # otherwise al = *(normal map + al) 05/add-to-eax Keyboard-normal-map/imm32 8a/byte-> *eax 0/r32/al $keyboard-interrupt-handler:select-map-done: # - if there's no character mapping, return { 3c/compare-al-and 0/imm8 74/jump-if-= break/disp8 # - store al in keyboard buffer 88/<- *ecx 0/r32/al # increment index fe/increment-byte *Keyboard-buffer:write # clear top nibble of index (keyboard buffer is circular) 80 4/subop/and-byte *Keyboard-buffer:write 0x0f/imm8 } $keyboard-interrupt-handler:end: # epilogue 9d/pop-flags 61/pop-all-registers fb/enable-interrupts cf/return-from-interrupt == data Keyboard-shift-pressed?: # boolean 0/imm32 Keyboard-ctrl-pressed?: # boolean 0/imm32 # var keyboard circular buffer Keyboard-buffer:write: # nibble 0/imm32 Keyboard-buffer:read: # nibble 0/imm32 Keyboard-buffer:data: # byte[16] 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 # Keyboard maps for translating keys to ASCII {{{ Keyboard-normal-map: 00 # es 1b # |<--- digits -------------->| - = backspace 31 32 33 34 35 36 37 38 39 30 2d 3d 08 # 0f # tab q w e r t y u i o p [ ] 09 71 77 65 72 74 79 75 69 6f 70 5b 5d # 1c # enter (newline) 0a 00 # 1e # a s d f g h j k l ; ' ` \ 61 73 64 66 67 68 6a 6b 6c 3b 27 60 00 5c # ^ left shift # 2c # z x c v b n m , . / * 7a 78 63 76 62 6e 6d 2c 2e 2f 00 2a # ^ right shift # 38 # space 00 20 # 3a 00 00 00 00 00 00 00 00 00 00 00 00 00 00 # 48 # ↑* ←* →* ↓* 82 00 00 80 00 83 00 00 81 # 51 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 # * - Not a valid ASCII/Unicode value. Keyboard-shift-map: 00 # es 1b # ! @ # $ % ^ & * ( ) _ + backspace 21 40 23 24 25 53 26 2a 28 29 5f 2b 08 # 0f # tab Q W E R T Y U I O P { } 09 51 57 45 52 54 59 55 49 5f 50 7b 7d # 1c # enter (newline) 0a 00 # 1e # A S D F G H J K L : " ~ | 41 53 44 46 47 48 4a 4b 4c 3a 22 7e 00 7c # 2c # Z X C V B N M < > ? * 5a 58 43 56 42 4e 4d 3c 3e 3f 00 2a # 38 # space 00 20 # 3a 00 00 00 00 00 00 00 00 00 00 00 00 00 00 # 48 # ↑* ←* →* ↓* 82 00 00 80 00 83 00 00 81 # 51 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 # * - Not a valid ASCII/Unicode value. Keyboard-ctrl-map: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 # 10 # ^q ^w ^e ^r ^t ^y ^u tb ^o ^p 11 17 05 12 14 19 15 09 1f 10 00 00 # 1c # carriage-return 0d 00 # 1e # ^a ^s ^d ^f ^g ^h ^j ^k ^l ^\ 01 13 04 06 07 08 0a 0b 0c 00 00 00 00 1c # 2c # ^z ^x ^c ^v ^b ^n ^m ^/ 1a 18 03 16 02 0e 0d 00 00 1f 00 00 # 38 # space 00 20 # 3a 00 00 00 00 00 00 00 00 00 00 00 00 00 00 # 48 # ↑* ←* →* ↓* 82 00 00 80 00 83 00 00 81 # 51 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 # * - Not a valid ASCII/Unicode value. # }}} Video-mode-info: # video mode info {{{ 0/imm16 # attributes 00 # winA 00 # winB # 04 0/imm16 # granularity 0/imm16 # winsize # 08 0/imm16 # segmentA 0/imm16 # segmentB # 0c 0/imm32 # realFctPtr (who knows) # 10 0/imm16 # pitch 0/imm16 # Xres 0/imm16 # Yres 0/imm16 # Wchar Ychar # 18 00 # planes 00 # bpp 00 # banks 00 # memory_model # 1c 00 # bank_size 00 # image_pages 00 # reserved # 1f 0/imm16 # red_mask red_position 0/imm16 # green_mask green_position 0/imm16 # blue_mask blue_position 0/imm16 # rsv_mask rsv_position 00 # directcolor_attributes # 28 Video-memory-addr: 0/imm32 # physbase # 2c # reserved for video mode info 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 # }}} ## Controlling IDE (ATA) hard disks # Uses 28-bit PIO mode. # Inspired by https://colorforth.github.io/ide.html # # Resources: # https://wiki.osdev.org/ATA_PIO_Mode # https://forum.osdev.org/viewtopic.php?f=1&p=167798 # read-sector, according to https://www.scs.stanford.edu/11wi-cs140/pintos/specs/ata-3-std.pdf == data # code disk # All ports are 8-bit except data-port, which is 16-bit. Primary-bus-primary-drive: # command-port: int (write) 0x1f7/imm32 # status-port: int (read) 0x1f7/imm32 # alternative-status-port: int (read) 0x3f6/imm32 # error-port: int (read) 0x1f1/imm32 # drive-and-head-port: int 0x1f6/imm32 # sector-count-port: int 0x1f2/imm32 # lba-low-port: int 0x1f3/imm32 # lba-mid-port: int 0x1f4/imm32 # lba-high-port: int 0x1f5/imm32 # data-port: int 0x1f0/imm32 # drive-code: byte # only drive-specific field 0xe0/imm32 # LBA mode also enabled # data disk # All ports are 8-bit except data-port, which is 16-bit. Primary-bus-secondary-drive: # command-port: int (write) 0x1f7/imm32 # status-port: int (read) 0x1f7/imm32 # alternative-status-port: int (read) 0x3f6/imm32 # error-port: int (read) 0x1f1/imm32 # drive-and-head-port: int 0x1f6/imm32 # sector-count-port: int 0x1f2/imm32 # lba-low-port: int 0x1f3/imm32 # lba-mid-port: int 0x1f4/imm32 # lba-high-port: int 0x1f5/imm32 # data-port: int 0x1f0/imm32 # drive-code: byte # only drive-specific field 0xf0/imm32 # LBA mode also enabled == code # No more than 0x100 sectors read-ata-disk: # disk: (addr disk), lba: int, n: int, out: (addr stream byte) # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax 51/push-ecx 52/push-edx # check precondition 81 7/subop/compare *(ebp+0x10) 0x100/imm32 { 7e/jump-if-<= break/disp8 (abort "read-ata-disk: no more than 0x100 sectors") } # check for drive (drive-exists? *(ebp+8)) # => eax 3d/compare-eax-and 0/imm32/false 0f 84/jump-if-= $read-ata-disk:end/disp32 # kick off read (ata-drive-select *(ebp+8) *(ebp+0xc)) (clear-ata-error *(ebp+8)) (ata-sector-count *(ebp+8) *(ebp+0x10)) (ata-lba *(ebp+8) *(ebp+0xc)) (ata-command *(ebp+8) 0x20) # read sectors with retries # for each sector { # poll for results #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "waiting for sector.." 7 0) #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "." 7 0) (while-ata-busy *(ebp+8)) (until-ata-data-available *(ebp+8)) #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "reading\n" 7 0) # var data-port/edx = disk->data-port 8b/-> *(ebp+8) 0/r32/eax 8b/-> *(eax+0x24) 2/r32/edx # emit results 31/xor %eax 0/r32/eax b9/copy-to-ecx 0x200/imm32 # 512 bytes per sector { 81 7/subop/compare %ecx 0/imm32 74/jump-if-= break/disp8 66 ed/read-port-dx-into-ax # write 2 bytes to stream one at a time (append-byte *(ebp+0x14) %eax) 49/decrement-ecx c1/shift 5/subop/right-padding-zeroes %eax 8/imm8 (append-byte *(ebp+0x14) %eax) 49/decrement-ecx eb/jump loop/disp8 } # next sector ff 1/subop/decrement *(ebp+0x10) #? (draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0 *(ebp+0x10) 0xc 0) 81 7/subop/compare *(ebp+0x10) 0/imm32 7e/jump-if-<= break/disp8 (wait-400ns *(ebp+8)) #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "next sector\n" 7 0) e9/jump loop/disp32 } $read-ata-disk:end: # . restore registers 5a/pop-to-edx 59/pop-to-ecx 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return write-ata-disk: # disk: (addr disk), lba: int, n: int, in: (addr stream byte) # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax 51/push-ecx 52/push-edx 53/push-ebx # check for drive (drive-exists? *(ebp+8)) # => eax 3d/compare-eax-and 0/imm32/false 0f 84/jump-if-= $write-ata-disk:end/disp32 # kick off write (ata-drive-select *(ebp+8) *(ebp+0xc)) (clear-ata-error *(ebp+8)) (ata-sector-count *(ebp+8) *(ebp+0x10)) (ata-lba *(ebp+8) *(ebp+0xc)) (ata-command *(ebp+8) 0x30) # write sectors with retries # for each sector #? (set-cursor-position 0 0 0) #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "0" 7 0) { # wait (while-ata-busy *(ebp+8)) (until-ata-ready-for-data *(ebp+8)) # var data-port/edx = disk->data-port 8b/-> *(ebp+8) 0/r32/eax 8b/-> *(eax+0x24) 2/r32/edx # send data b9/copy-to-ecx 0x200/imm32 # 512 bytes per sector # . var first-byte/ebx: byte # . when it's more than 0xff, we're at an even-numbered byte bb/copy-to-ebx 0xffff/imm32 #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "D" 7 0) $write-ata-disk:store-sector: { 81 7/subop/compare %ecx 0/imm32 74/jump-if-= break/disp8 # this loop is slow, but the ATA spec also requires a small delay (stream-empty? *(ebp+0x14)) # => eax 3d/compare-eax-and 0/imm32/false 75/jump-if-!= break/disp8 # read byte from stream (read-byte *(ebp+0x14)) # => eax # if we're at an odd-numbered byte, save it to first-byte 81 7/subop/compare %ebx 0xff/imm32 { 7e/jump-if-<= break/disp8 89/<- %ebx 0/r32/eax eb/jump $write-ata-disk:store-sector/disp8 } # otherwise OR it with first-byte and write it out c1/shift 4/subop/left %eax 8/imm8 09/or %eax 3/r32/ebx 66 ef/write-ax-into-port-dx 49/decrement-ecx 49/decrement-ecx # reset first-byte bb/copy-to-ebx 0xffff/imm32 eb/jump loop/disp8 } # write out final first-byte if necessary #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "I" 7 0) 81 7/subop/compare %ebx 0xff/imm32 { 7f/jump-if-> break/disp8 89/<- %eax 3/r32/ebx 66 ef/write-ax-into-port-dx 49/decrement-ecx 49/decrement-ecx } # pad zeroes #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "P" 7 0) 31/xor %eax 0/r32/eax { 81 7/subop/compare %ecx 0/imm32 74/jump-if-= break/disp8 66 ef/write-ax-into-port-dx 49/decrement-ecx 49/decrement-ecx eb/jump loop/disp8 } # next sector #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "N" 7 0) ff 1/subop/decrement *(ebp+0x10) 81 7/subop/compare *(ebp+0x10) 0/imm32 7e/jump-if-<= break/disp8 #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "W" 7 0) (wait-400ns *(ebp+8)) #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "L" 7 0) e9/jump loop/disp32 } #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "F" 7 0) (flush-ata-cache *(ebp+8)) #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "Y" 7 0) $write-ata-disk:end: # . restore registers 5b/pop-to-ebx 5a/pop-to-edx 59/pop-to-ecx 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return # disk helpers {{{ drive-exists?: # disk: (addr disk) -> _/eax: boolean # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 52/push-edx # check for floating bus { 31/xor %eax 0/r32/eax ba/copy-to-edx 0x1f7/imm32 ec/read-port-dx-into-al 3d/compare-eax-and 0xff/imm32 # if eax is 0xff, primary bus has no drives b8/copy-to-eax 0/imm32/false 0f 84/jump-if-= $drive-exists?:end/disp32 } # identify (ata-drive-select *(ebp+8) 0) (ata-sector-count *(ebp+8) 0) (ata-lba *(ebp+8) 0) (ata-command *(ebp+8) 0xec) # identify # var status-port/edx = disk->status-port 8b/-> *(ebp+8) 0/r32/eax 8b/-> *(eax+4) 2/r32/edx # 4 = status-port offset # read status port # TODO: might need to spin here for 400ns: https://wiki.osdev.org/index.php?title=ATA_PIO_Mode&oldid=25664#400ns_delays 31/xor %eax 0/r32/eax ec/read-port-dx-into-al # if eax is 0, drive does not exist 3d/compare-eax-and 0/imm32 { 74/jump-if-= break/disp8 b8/copy-to-eax 1/imm32/true eb/jump $drive-exists?:complete-identify/disp8 } # TODO: might need to perform remaining steps at https://wiki.osdev.org/index.php?title=ATA_PIO_Mode&oldid=25664#IDENTIFY_command b8/copy-to-eax 0/imm32/false $drive-exists?:complete-identify: 50/push-eax # var data-port/edx = disk->data-port 8b/-> *(ebp+8) 0/r32/eax 8b/-> *(eax+0x24) 2/r32/edx # 0x24 = data-port offset # clear FIFO from the drive b9/copy-to-ecx 0x200/imm32 { 81 7/subop/compare %ecx 0/imm32 74/jump-if-= break/disp8 # read 4 bytes ed/read-port-dx-into-eax 49/decrement-ecx 49/decrement-ecx 49/decrement-ecx 49/decrement-ecx eb/jump loop/disp8 } 58/pop-to-eax $drive-exists?:end: # . restore registers 5a/pop-to-edx # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return ata-drive-select: # disk: (addr disk), lba: int # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax 52/push-edx 56/push-esi # esi = disk 8b/-> *(ebp+8) 6/r32/esi # var drive-head/edx: byte = lba >> 24 8b/-> *(ebp+0xc) 2/r32/edx c1/shift 5/subop/right-padding-zeroes %edx 0x18/imm8 # var drive-code/eax: byte = disk->drive-code | drive-head 8b/-> *(esi+0x28) 0/r32/eax # 0x28 = drive-code offset 09/or= %eax 2/r32/edx # var drive-and-head-port/edx: int 8b/-> *(esi+0x10) 2/r32/edx # 0x10 = drive-and-head-port offset ee/write-al-into-port-dx $ata-drive-select:end: # . restore registers 5e/pop-to-esi 5a/pop-to-edx 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return clear-ata-error: # disk: (addr disk) # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax 52/push-edx # var error-port/edx = disk->error-port 8b/-> *(ebp+8) 0/r32/eax 8b/-> *(eax+0xc) 2/r32/edx # 0xc = error-port offset # b8/copy-to-eax 0/imm32 ee/write-al-into-port-dx $ata-error:end: # . restore registers 5a/pop-to-edx 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return ata-sector-count: # disk: (addr disk), n: byte # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax 52/push-edx # var sector-count-port/edx = disk->sector-count-port 8b/-> *(ebp+8) 0/r32/eax 8b/-> *(eax+0x14) 2/r32/edx # 0x14 = sector-count-port offset # 8b/-> *(ebp+0xc) 0/r32/eax ee/write-al-into-port-dx $ata-sector-count:end: # . restore registers 5a/pop-to-edx 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return ata-lba: # disk: (addr disk), lba: int # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax 52/push-edx # var port/edx = disk->port 8b/-> *(ebp+8) 0/r32/eax 8b/-> *(eax+0x18) 2/r32/edx # 0x18 = lba-low-port offset # eax = lba 8b/-> *(ebp+0xc) 0/r32/eax # lo ee/write-al-into-port-dx # mid 42/increment-dx # lba-mid-port c1/shift 5/subop/right-padding-zeroes %eax 8/imm8 ee/write-al-into-port-dx # hi 42/increment-dx # lba-high-port c1/shift 5/subop/right-padding-zeroes %eax 8/imm8 ee/write-al-into-port-dx $ata-lba:end: # . restore registers 5a/pop-to-edx 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return ata-command: # disk: (addr disk), cmd: byte # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax 52/push-edx # var command-port/edx = disk->command-port 8b/-> *(ebp+8) 0/r32/eax 8b/-> *(eax+0) 2/r32/edx # 0 = command-port offset # 8b/-> *(ebp+0xc) 0/r32/eax ee/write-al-into-port-dx $ata-command:end: # . restore registers 5a/pop-to-edx 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return while-ata-busy: # disk: (addr disk) # . save registers 50/push-eax 52/push-edx # var status-port/edx = disk->status-port 8b/-> *(ebp+8) 0/r32/eax 8b/-> *(eax+4) 2/r32/edx # 4 = status-port offset { ec/read-port-dx-into-al a8/test-bits-in-al 0x80/imm8/bsy # set zf if bit 7 (most significant) is not set 75/jump-if-zf-not-set-and-bit-7-set loop/disp8 } $while-ata-busy:end: # . restore registers 5a/pop-to-edx 58/pop-to-eax # . epilogue c3/return until-ata-data-available: # disk: (addr disk) # . save registers 50/push-eax 52/push-edx # var status-port/edx = disk->status-port 8b/-> *(ebp+8) 0/r32/eax 8b/-> *(eax+4) 2/r32/edx # 4 = status-port offset { ec/read-port-dx-into-al a8/test-bits-in-al 8/imm8/drq # set zf if bit 3 is not set 74/jump-if-zf-set-and-bit-3-not-set loop/disp8 } $until-ata-data-available:end: # . restore registers 5a/pop-to-edx 58/pop-to-eax # . epilogue c3/return until-ata-ready-for-data: (until-ata-data-available) c3/return # https://wiki.osdev.org/index.php?title=ATA_PIO_Mode&oldid=25664#400ns_delays wait-400ns: # disk: (addr disk) # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax 51/push-ecx 52/push-edx #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "waiting 400ns\n" 7 0) # var status-port/edx = disk->status-port 8b/-> *(ebp+8) 0/r32/eax 8b/-> *(eax+4) 2/r32/edx # 4 = status-port offset # b9/copy-to-ecx 0x10/imm32 { 81 7/subop/compare %ecx 0/imm32 74/jump-if-= break/disp8 #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "." 7 0) ec/read-port-dx-into-al 49/decrement-ecx eb/jump loop/disp8 } $wait-400ns:end: # . restore registers 5a/pop-to-edx 59/pop-to-ecx 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return # Flush cache isn't in ATA 3, but it shows up by the ATA 5 spec: # http://hddguru.com/download/documentation/ATA-ATAPI-standard-5/ATA-ATAPI-5.pdf flush-ata-cache: # disk: (addr disk) # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # (ata-drive-select *(ebp+8) 0) (ata-command *(ebp+8) 0xe7) # flush cache #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "W" 7 0) (while-ata-busy *(ebp+8)) #? (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "X" 7 0) # TODO: seems unneeded? works for a single sector but Qemu hangs with multiple # sectors. Data is still written. #? (until-ata-ready-for-data *(ebp+8)) $flush-ata-cache:end: # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return # }}} ## Controlling a PS/2 mouse # Uses no IRQs, just polling. # Thanks Dave Long: https://github.com/jtauber/cleese/blob/master/necco/kernel/bochs/py8042.py # # Resources: # https://wiki.osdev.org/Mouse_Input # results x/eax, y/ecx range from -256 to +255 # See https://wiki.osdev.org/index.php?title=Mouse_Input&oldid=25663#Format_of_First_3_Packet_Bytes read-mouse-event: # -> _/eax: int, _/ecx: int # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 52/push-edx 53/push-ebx # if no event, return 0, 0 b8/copy-to-eax 0/imm32 b9/copy-to-ecx 0/imm32 (any-mouse-event?) # => eax 3d/compare-eax-and 0/imm32/false 74/jump-if-= $read-mouse-event:end/disp8 # var f1/edx: byte = inb(0x60) 31/xor %eax 0/r32/eax e4/read-port-into-al 0x60/imm8 89/<- %edx 0/r32/eax (wait-for-mouse-event) # var dx/ebx: byte = inb(0x60) 31/xor %eax 0/r32/eax e4/read-port-into-al 0x60/imm8 89/<- %ebx 0/r32/eax (wait-for-mouse-event) # var dy/ecx: byte = inb(0x60) 31/xor %eax 0/r32/eax e4/read-port-into-al 0x60/imm8 89/<- %ecx 0/r32/eax # eax = dx 89/<- %eax 3/r32/ebx # if (f1 & 0x10) dx = -dx { f6 0/subop/test-bits %dl 0x10/imm8 74/jump-if-zero break/disp8 0d/or-eax-with 0xffffff00/imm32 } # if (f1 & 0x20) dy = -dy { f6 0/subop/test-bits %dl 0x20/imm8 74/jump-if-zero break/disp8 81 1/subop/or %ecx 0xffffff00/imm32 } $read-mouse-event:end: # . restore registers 5b/pop-to-ebx 5a/pop-to-edx # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return # mouse helpers {{{ wait-for-mouse-event: # . save registers 50/push-eax # { (any-mouse-event?) # => eax 3d/compare-eax-and 0/imm32/false 74/jump-if-= loop/disp8 } $wait-for-mouse-event:end: # . restore registers 58/pop-to-eax # . c3/return any-mouse-event?: # -> _/eax: boolean 31/xor %eax 0/r32/eax # 0x1 bit: there's data from the keyboard controller # 0x20 bit: it's data from the aux port (the mouse) e4/read-port-into-al 0x60/imm8 24/and-al-with 0x21/imm8 3c/compare-al-with 0x21/imm8 0f 94/set-byte-if-= %al c3/return initialize-mouse: (enable-keyboard-controller-aux-device) # tell mouse to use default settings (send-mouse-command 0xf6) # enable mouse (send-mouse-command 0xf4) c3/return enable-keyboard-controller-aux-device: (command-keyboard-controller 0xa8) c3/return send-mouse-command: # command: byte # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # (command-keyboard-controller 0xd4) (send-keyboard-controller-data *(ebp+8)) (wait-for-ack-from-mouse) $send-mouse-command:end: # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return wait-for-ack-from-mouse: # . save registers 50/push-eax { (read-keyboard-controller-data) # => eax 3d/compare-eax-with 0xfa/imm32 75/jump-if-!= loop/disp8 } $wait-for-ack-from-mouse:end: # . restore registers 58/pop-eax c3/return command-keyboard-controller: # command: byte # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax # (poll-keyboard-controller-to-write) 8b/-> *(ebp+8) 0/r32/eax e6/write-al-into-port 0x64/imm8 $command-keyboard-controller:end: # . restore registers 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return send-keyboard-controller-data: # data: byte # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax # (poll-keyboard-controller-to-write) 8b/-> *(ebp+8) 0/r32/eax e6/write-al-into-port 0x60/imm8 $send-keyboard-controller-data:end: # . restore registers 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return read-keyboard-controller-data: # -> _/eax: byte (poll-keyboard-controller-to-read-data-port) 31/xor %eax 0/r32/eax e4/read-port-into-al 0x60/imm8 c3/return poll-keyboard-controller-to-write: # . save registers 50/push-eax # "All output to port 0x60 or 0x64 must be preceded by waiting for bit 1 # (value=2) of port 0x64 to become clear." # https://wiki.osdev.org/index.php?title=Mouse_Input&oldid=25663#Waiting_to_Send_Bytes_to_Port_0x60_and_0x64 { e4/read-port-into-al 0x64/imm8 a8/test-bits-in-al 2/imm8 # set zf if bit 1 (second-least significant) is not set 75/jump-if-zf-not-set-and-bit-1-set loop/disp8 } $poll-keyboard-controller-to-write:end: # . restore registers 58/pop-to-eax # . epilogue c3/return poll-keyboard-controller-to-read-data-port: # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax # "Bytes cannot be read from port 0x60 until bit 0 (value=1) of port 0x64 is set." # https://wiki.osdev.org/index.php?title=Mouse_Input&oldid=25663#Waiting_to_Send_Bytes_to_Port_0x60_and_0x64 { e4/read-port-into-al 0x64/imm8 a8/test-bits-in-al 1/imm8 # set zf if bit 0 (least significant) is not set 74/jump-if-zf-set-and-bit-0-not-set loop/disp8 } $poll-keyboard-controller-to-read-data-port:end: # . restore registers 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return # }}} # vim:ft=subx


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