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<a href='https://github.com/akkartik/mu/blob/main/103glyph.subx'>https://github.com/akkartik/mu/blob/main/103glyph.subx</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr"> 1 </span><span class="subxComment"># Use the built-in font to draw glyphs to screen.</span>
<span id="L2" class="LineNr"> 2 </span><span class="subxComment"># <a href="https://en.wikipedia.org/wiki/Glyph#Typography">https://en.wikipedia.org/wiki/Glyph#Typography</a></span>
<span id="L3" class="LineNr"> 3 </span><span class="subxComment"># Extremely hacky support for combining characters.</span>
<span id="L4" class="LineNr"> 4 </span><span class="subxComment"># <a href="https://en.wikipedia.org/wiki/Code_point">https://en.wikipedia.org/wiki/Code_point</a></span>
<span id="L5" class="LineNr"> 5 </span><span class="subxComment"># <a href="https://en.wikipedia.org/wiki/Combining_character">https://en.wikipedia.org/wiki/Combining_character</a></span>
<span id="L6" class="LineNr"> 6 </span><span class="subxComment"># All we support is drawing combining characters atop the same screen cell as</span>
<span id="L7" class="LineNr"> 7 </span><span class="subxComment"># a single base code point. See the overlay? arguments below.</span>
<span id="L8" class="LineNr"> 8 </span><span class="subxComment">#</span>
<span id="L9" class="LineNr"> 9 </span><span class="subxComment"># We need to do this in machine code because Mu doesn't have global variables</span>
<span id="L10" class="LineNr"> 10 </span><span class="subxComment"># yet (for the start of the font).</span>
<span id="L11" class="LineNr"> 11 </span>
<span id="L12" class="LineNr"> 12 </span>== code
<span id="L13" class="LineNr"> 13 </span>
<span id="L14" class="LineNr"> 14 </span><span class="subxComment"># The Mu computer's screen is 1024px wide and 768px tall.</span>
<span id="L15" class="LineNr"> 15 </span><span class="subxComment"># The Mu computer's font is 8px wide and 16px tall.</span>
<span id="L16" class="LineNr"> 16 </span><span class="subxComment"># Therefore 'x' here is in [0, 128), and 'y' is in [0, 48)</span>
<span id="L17" class="LineNr"> 17 </span><span class="subxComment"># Doesn't update the cursor; where the cursor should go after printing the</span>
<span id="L18" class="LineNr"> 18 </span><span class="subxComment"># current code-point is a higher-level concern.</span>
<span id="L19" class="LineNr"> 19 </span><span class="subxFunction">draw-code-point-on-real-screen</span>: <span class="subxComment"># c: code-point, x: int, y: int, color: int, background-color: int -> _/eax</span>
<span id="L20" class="LineNr"> 20 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L21" class="LineNr"> 21 </span> 55/push-ebp
<span id="L22" class="LineNr"> 22 </span> 89/<- %ebp 4/r32/esp
<span id="L23" class="LineNr"> 23 </span> <span class="subxComment">#</span>
<span id="L24" class="LineNr"> 24 </span> (<a href='103glyph.subx.html#L87'>draw-code-point-on-screen-buffer</a> *<span class="SpecialChar"><a href='boot.subx.html#L675'>Video-memory-addr</a></span> *(ebp+8) *(ebp+0xc) *(ebp+0x10) *(ebp+0x14) *(ebp+0x18) 0 0x80 0x30) <span class="subxComment"># 0/no-overlay => eax</span>
<span id="L25" class="LineNr"> 25 </span><span class="Constant">$draw-code-point-on-real-screen:end</span>:
<span id="L26" class="LineNr"> 26 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L27" class="LineNr"> 27 </span> 89/<- %esp 5/r32/ebp
<span id="L28" class="LineNr"> 28 </span> 5d/pop-to-ebp
<span id="L29" class="LineNr"> 29 </span> c3/return
<span id="L30" class="LineNr"> 30 </span>
<span id="L31" class="LineNr"> 31 </span><span class="subxFunction">overlay-code-point-on-real-screen</span>: <span class="subxComment"># c: code-point, x: int, y: int, color: int, background-color: int -> _/eax</span>
<span id="L32" class="LineNr"> 32 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L33" class="LineNr"> 33 </span> 55/push-ebp
<span id="L34" class="LineNr"> 34 </span> 89/<- %ebp 4/r32/esp
<span id="L35" class="LineNr"> 35 </span> <span class="subxComment">#</span>
<span id="L36" class="LineNr"> 36 </span> (<a href='103glyph.subx.html#L87'>draw-code-point-on-screen-buffer</a> *<span class="SpecialChar"><a href='boot.subx.html#L675'>Video-memory-addr</a></span> *(ebp+8) *(ebp+0xc) *(ebp+0x10) *(ebp+0x14) *(ebp+0x18) 1 0x80 0x30) <span class="subxComment"># 1/overlay => eax</span>
<span id="L37" class="LineNr"> 37 </span><span class="Constant">$overlay-code-point-on-real-screen:end</span>:
<span id="L38" class="LineNr"> 38 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L39" class="LineNr"> 39 </span> 89/<- %esp 5/r32/ebp
<span id="L40" class="LineNr"> 40 </span> 5d/pop-to-ebp
<span id="L41" class="LineNr"> 41 </span> c3/return
<span id="L42" class="LineNr"> 42 </span>
<span id="L43" class="LineNr"> 43 </span><span class="subxFunction">draw-code-point-on-screen-array</span>: <span class="subxComment"># screen-data: (addr array byte), c: code-point, x: int, y: int, color: int, background-color: int, screen-width: int, screen-height: int -> _/eax: int</span>
<span id="L44" class="LineNr"> 44 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L45" class="LineNr"> 45 </span> 55/push-ebp
<span id="L46" class="LineNr"> 46 </span> 89/<- %ebp 4/r32/esp
<span id="L47" class="LineNr"> 47 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L48" class="LineNr"> 48 </span> 51/push-ecx
<span id="L49" class="LineNr"> 49 </span> 52/push-edx
<span id="L50" class="LineNr"> 50 </span> <span class="subxComment"># if screen-width*screen-height > len(screen-data) abort</span>
<span id="L51" class="LineNr"> 51 </span> {
<span id="L52" class="LineNr"> 52 </span> <span class="subxComment"># ecx = len(screen-data)</span>
<span id="L53" class="LineNr"> 53 </span> 8b/-> *(ebp+8) 1/r32/ecx
<span id="L54" class="LineNr"> 54 </span> 8b/-> *ecx 1/r32/ecx
<span id="L55" class="LineNr"> 55 </span> <span class="subxComment"># eax = screen-width*screen-height</span>
<span id="L56" class="LineNr"> 56 </span> ba/copy-to-edx 0/imm32
<span id="L57" class="LineNr"> 57 </span> 8b/-> *(ebp+0x20) 0/r32/eax
<span id="L58" class="LineNr"> 58 </span> f7 4/subop/multiply-into-eax *(ebp+0x24)
<span id="L59" class="LineNr"> 59 </span> 81 7/subop/compare %edx 0/imm32
<span id="L60" class="LineNr"> 60 </span> 0f 85/jump-if-!= $draw-code-point-on-screen-array:overflow/disp32
<span id="L61" class="LineNr"> 61 </span> <span class="subxComment"># if (eax > ecx) abort</span>
<span id="L62" class="LineNr"> 62 </span> 39/compare %eax 1/r32/ecx
<span id="L63" class="LineNr"> 63 </span> 0f 8f/jump-if-> $draw-code-point-on-screen-array:<a href='317abort.subx.html#L5'>abort</a>/disp32
<span id="L64" class="LineNr"> 64 </span> }
<span id="L65" class="LineNr"> 65 </span> <span class="subxComment"># eax = screen-data+4 (skip length)</span>
<span id="L66" class="LineNr"> 66 </span> 8b/-> *(ebp+8) 0/r32/eax
<span id="L67" class="LineNr"> 67 </span> 05/add-to-eax 4/imm32
<span id="L68" class="LineNr"> 68 </span> <span class="subxComment">#</span>
<span id="L69" class="LineNr"> 69 </span> (<a href='103glyph.subx.html#L87'>draw-code-point-on-screen-buffer</a> %eax *(ebp+0xc) *(ebp+0x10) *(ebp+0x14) *(ebp+0x18) *(ebp+0x1c) 1 *(ebp+0x20) *(ebp+0x24)) <span class="subxComment"># => eax</span>
<span id="L70" class="LineNr"> 70 </span><span class="Constant">$draw-code-point-on-screen-array:end</span>:
<span id="L71" class="LineNr"> 71 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L72" class="LineNr"> 72 </span> 5a/pop-to-edx
<span id="L73" class="LineNr"> 73 </span> 59/pop-to-ecx
<span id="L74" class="LineNr"> 74 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L75" class="LineNr"> 75 </span> 89/<- %esp 5/r32/ebp
<span id="L76" class="LineNr"> 76 </span> 5d/pop-to-ebp
<span id="L77" class="LineNr"> 77 </span> c3/return
<span id="L78" class="LineNr"> 78 </span>
<span id="L79" class="LineNr"> 79 </span><span class="Constant">$draw-code-point-on-screen-array:overflow</span>:
<span id="L80" class="LineNr"> 80 </span> (<a href='317abort.subx.html#L5'>abort</a> <span class="Constant">"draw-code-point-on-screen-array: <a href='500fake-screen.mu.html#L16'>screen</a> dimensions too large"</span>)
<span id="L81" class="LineNr"> 81 </span>
<span id="L82" class="LineNr"> 82 </span><span class="Constant">$draw-code-point-on-screen-array:<a href='317abort.subx.html#L5'>abort</a></span>:
<span id="L83" class="LineNr"> 83 </span> (<a href='317abort.subx.html#L5'>abort</a> <span class="Constant">"draw-code-point-on-screen-array: coordinates are off the screen. Are the <a href='500fake-screen.mu.html#L16'>screen</a> dimensions correct?"</span>)
<span id="L84" class="LineNr"> 84 </span>
<span id="L85" class="LineNr"> 85 </span><span class="subxComment"># 'buffer' here is not a valid Mu type: a naked address without a length.</span>
<span id="L86" class="LineNr"> 86 </span><span class="subxComment"># returns number of 8x16 units printed to screen (1 or 2).</span>
<span id="L87" class="LineNr"> 87 </span><span class="subxFunction">draw-code-point-on-screen-buffer</span>: <span class="subxComment"># buffer: (addr byte), c: code-point, x: int, y: int, color: int, background-color: int, overlay?: boolean, screen-width: int, screen-height: int -> _/eax: int</span>
<span id="L88" class="LineNr"> 88 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L89" class="LineNr"> 89 </span> 55/push-ebp
<span id="L90" class="LineNr"> 90 </span> 89/<- %ebp 4/r32/esp
<span id="L91" class="LineNr"> 91 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L92" class="LineNr"> 92 </span> 56/push-esi
<span id="L93" class="LineNr"> 93 </span> <span class="subxComment"># switch screen-width and screen-height from code-point to pixel units</span>
<span id="L94" class="LineNr"> 94 </span> c1 4/subop/shift-left *(ebp+24) 3/imm8/log2-font-width
<span id="L95" class="LineNr"> 95 </span> c1 4/subop/shift-left *(ebp+28) 4/imm8/log2-font-height
<span id="L96" class="LineNr"> 96 </span> <span class="subxComment"># esi = c</span>
<span id="L97" class="LineNr"> 97 </span> 8b/-> *(ebp+0xc) 6/r32/esi
<span id="L98" class="LineNr"> 98 </span> <span class="subxComment"># if (c >= 4352) return # unicode planes supported: latin, greek, cyrillic, armenian, hebrew, arabic, syriac, thaana, n'ko, indian (iscii), sinhala, thai, lao, tibetan, myanmar, georgian</span>
<span id="L99" class="LineNr"> 99 </span> <span class="subxComment"># next few to support: CJK, ethiopic, cherokee, ...</span>
<span id="L100" class="LineNr">100 </span> 81 7/subop/compare %esi 0x1100/imm32/4352
<span id="L101" class="LineNr">101 </span> 0f 8d/jump-if->= $draw-code-point-on-screen-buffer:end/disp32
<span id="L102" class="LineNr">102 </span> <span class="subxComment"># var letter-bitmap/esi = font[c]</span>
<span id="L103" class="LineNr">103 </span> 69/multiply %esi 0x22/imm32/glyph-size 6/r32/esi
<span id="L104" class="LineNr">104 </span> 81 0/subop/add %esi 0x0010000c/imm32/Font <span class="subxComment"># see boot.subx</span>
<span id="L105" class="LineNr">105 </span> <span class="subxComment"># dispatch based on letter-bitmap->size</span>
<span id="L106" class="LineNr">106 </span> b8/copy-to-eax 0/imm32
<span id="L107" class="LineNr">107 </span> 8a/byte-> *esi 0/r32/AL
<span id="L108" class="LineNr">108 </span> 46/increment-esi <span class="subxComment"># skip size</span>
<span id="L109" class="LineNr">109 </span> 46/increment-esi <span class="subxComment"># skip size</span>
<span id="L110" class="LineNr">110 </span> 3d/compare-eax-and 8/imm32
<span id="L111" class="LineNr">111 </span> {
<span id="L112" class="LineNr">112 </span> 75/jump-if-!= <span class="Constant">break</span>/disp8
<span id="L113" class="LineNr">113 </span> (<a href='103glyph.subx.html#L187'>draw-narrow-code-point-on-screen-buffer</a> *(ebp+8) %esi *(ebp+0x10) *(ebp+0x14) *(ebp+0x18) *(ebp+0x1c) *(ebp+0x20) *(ebp+0x24) *(ebp+0x28))
<span id="L114" class="LineNr">114 </span> b8/copy-to-eax 1/imm32
<span id="L115" class="LineNr">115 </span> eb/jump $draw-code-point-on-screen-buffer:end/disp8
<span id="L116" class="LineNr">116 </span> }
<span id="L117" class="LineNr">117 </span> (<a href='103glyph.subx.html#L233'>draw-wide-code-point-on-screen-buffer</a> *(ebp+8) %esi *(ebp+0x10) *(ebp+0x14) *(ebp+0x18) *(ebp+0x1c) *(ebp+0x20) *(ebp+0x24) *(ebp+0x28))
<span id="L118" class="LineNr">118 </span> b8/copy-to-eax 2/imm32
<span id="L119" class="LineNr">119 </span><span class="Constant">$draw-code-point-on-screen-buffer:end</span>:
<span id="L120" class="LineNr">120 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L121" class="LineNr">121 </span> 5e/pop-to-esi
<span id="L122" class="LineNr">122 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L123" class="LineNr">123 </span> 89/<- %esp 5/r32/ebp
<span id="L124" class="LineNr">124 </span> 5d/pop-to-ebp
<span id="L125" class="LineNr">125 </span> c3/return
<span id="L126" class="LineNr">126 </span>
<span id="L127" class="LineNr">127 </span><span class="subxFunction">wide-code-point?</span>: <span class="subxComment"># c: code-point -> _/eax: boolean</span>
<span id="L128" class="LineNr">128 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L129" class="LineNr">129 </span> 55/push-ebp
<span id="L130" class="LineNr">130 </span> 89/<- %ebp 4/r32/esp
<span id="L131" class="LineNr">131 </span> <span class="subxComment"># eax = c</span>
<span id="L132" class="LineNr">132 </span> 8b/-> *(ebp+8) 0/r32/eax
<span id="L133" class="LineNr">133 </span> <span class="subxComment"># if (c >= 4352) return false</span>
<span id="L134" class="LineNr">134 </span> 3d/compare-eax-and 0x1100/imm32
<span id="L135" class="LineNr">135 </span> 0f 8d/jump-if->= $wide-code-point?:return-false/disp32
<span id="L136" class="LineNr">136 </span> <span class="subxComment"># var letter-bitmap/eax = font[c]</span>
<span id="L137" class="LineNr">137 </span> 69/multiply %eax 0x22/imm32/glyph-size 0/r32/eax
<span id="L138" class="LineNr">138 </span> 05/add-to-eax 0x0010000c/imm32/Font <span class="subxComment"># see boot.subx</span>
<span id="L139" class="LineNr">139 </span> <span class="subxComment"># dispatch based on letter-bitmap->size</span>
<span id="L140" class="LineNr">140 </span> 8a/byte-> *eax 0/r32/AL
<span id="L141" class="LineNr">141 </span> 25/and-eax-with 0xff/imm32
<span id="L142" class="LineNr">142 </span> 3d/compare-eax-and 8/imm32
<span id="L143" class="LineNr">143 </span> 0f 95/set-if-!= %eax
<span id="L144" class="LineNr">144 </span><span class="Constant">$wide-code-point?:end</span>:
<span id="L145" class="LineNr">145 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L146" class="LineNr">146 </span> 89/<- %esp 5/r32/ebp
<span id="L147" class="LineNr">147 </span> 5d/pop-to-ebp
<span id="L148" class="LineNr">148 </span> c3/return
<span id="L149" class="LineNr">149 </span>
<span id="L150" class="LineNr">150 </span><span class="Constant">$wide-code-point?:return-false</span>:
<span id="L151" class="LineNr">151 </span> b8/copy-to-eax 0/imm32/false
<span id="L152" class="LineNr">152 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L153" class="LineNr">153 </span> 89/<- %esp 5/r32/ebp
<span id="L154" class="LineNr">154 </span> 5d/pop-to-ebp
<span id="L155" class="LineNr">155 </span> c3/return
<span id="L156" class="LineNr">156 </span>
<span id="L157" class="LineNr">157 </span><span class="subxFunction">combining-code-point?</span>: <span class="subxComment"># c: code-point -> _/eax: boolean</span>
<span id="L158" class="LineNr">158 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L159" class="LineNr">159 </span> 55/push-ebp
<span id="L160" class="LineNr">160 </span> 89/<- %ebp 4/r32/esp
<span id="L161" class="LineNr">161 </span> <span class="subxComment"># eax = c</span>
<span id="L162" class="LineNr">162 </span> 8b/-> *(ebp+8) 0/r32/eax
<span id="L163" class="LineNr">163 </span> <span class="subxComment"># if (c >= 4352) return false</span>
<span id="L164" class="LineNr">164 </span> 3d/compare-eax-and 0x1100/imm32
<span id="L165" class="LineNr">165 </span> 0f 8d/jump-if->= $combining-code-point?:return-false/disp32
<span id="L166" class="LineNr">166 </span> <span class="subxComment"># var letter-bitmap/eax = font[c]</span>
<span id="L167" class="LineNr">167 </span> 69/multiply %eax 0x22/imm32/glyph-size 0/r32/eax
<span id="L168" class="LineNr">168 </span> 05/add-to-eax 0x0010000c/imm32/Font <span class="subxComment"># see boot.subx</span>
<span id="L169" class="LineNr">169 </span> <span class="subxComment"># dispatch based on letter-bitmap->is-combine?</span>
<span id="L170" class="LineNr">170 </span> 8a/byte-> *(eax+1) 0/r32/AL
<span id="L171" class="LineNr">171 </span> 25/and-eax-with 0xff/imm32
<span id="L172" class="LineNr">172 </span><span class="Constant">$combining-code-point?:end</span>:
<span id="L173" class="LineNr">173 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L174" class="LineNr">174 </span> 89/<- %esp 5/r32/ebp
<span id="L175" class="LineNr">175 </span> 5d/pop-to-ebp
<span id="L176" class="LineNr">176 </span> c3/return
<span id="L177" class="LineNr">177 </span>
<span id="L178" class="LineNr">178 </span><span class="Constant">$combining-code-point?:return-false</span>:
<span id="L179" class="LineNr">179 </span> b8/copy-to-eax 0/imm32/false
<span id="L180" class="LineNr">180 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L181" class="LineNr">181 </span> 89/<- %esp 5/r32/ebp
<span id="L182" class="LineNr">182 </span> 5d/pop-to-ebp
<span id="L183" class="LineNr">183 </span> c3/return
<span id="L184" class="LineNr">184 </span>
<span id="L185" class="LineNr">185 </span><span class="subxComment"># buffer: naked address to raw screen RAM without a length</span>
<span id="L186" class="LineNr">186 </span><span class="subxComment"># letter-bitmap: naked address to 8-pixel wide font glyph</span>
<span id="L187" class="LineNr">187 </span><span class="subxFunction">draw-narrow-code-point-on-screen-buffer</span>: <span class="subxComment"># buffer: (addr byte), letter-bitmap: (addr byte), x: int, y: int, color: int, background-color: int, overlay?: boolean, screen-width: int, screen-height: int</span>
<span id="L188" class="LineNr">188 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L189" class="LineNr">189 </span> 55/push-ebp
<span id="L190" class="LineNr">190 </span> 89/<- %ebp 4/r32/esp
<span id="L191" class="LineNr">191 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L192" class="LineNr">192 </span> 52/push-edx
<span id="L193" class="LineNr">193 </span> 53/push-ebx
<span id="L194" class="LineNr">194 </span> 56/push-esi
<span id="L195" class="LineNr">195 </span> 57/push-edi
<span id="L196" class="LineNr">196 </span> <span class="subxComment"># esi = letter-bitmap</span>
<span id="L197" class="LineNr">197 </span> 8b/-> *(ebp+0xc) 6/r32/esi
<span id="L198" class="LineNr">198 </span> <span class="subxComment"># var ycurr/edx: int = y*16</span>
<span id="L199" class="LineNr">199 </span> 8b/-> *(ebp+0x14) 2/r32/edx
<span id="L200" class="LineNr">200 </span> c1 4/subop/shift-left %edx 4/imm8
<span id="L201" class="LineNr">201 </span> <span class="subxComment"># var ymax/edi: int = ycurr + 16</span>
<span id="L202" class="LineNr">202 </span> 8b/-> *(ebp+0x14) 7/r32/edi
<span id="L203" class="LineNr">203 </span> c1 4/subop/shift-left %edi 4/imm8
<span id="L204" class="LineNr">204 </span> 81 0/subop/add %edi 0x10/imm32
<span id="L205" class="LineNr">205 </span> {
<span id="L206" class="LineNr">206 </span> <span class="subxComment"># if (ycurr >= ymax) break</span>
<span id="L207" class="LineNr">207 </span> 39/compare %edx 7/r32/edi
<span id="L208" class="LineNr">208 </span> 0f 8d/jump-if->= <span class="Constant">break</span>/disp32
<span id="L209" class="LineNr">209 </span> <span class="subxComment"># var row-bitmap/ebx: byte = *letter-bitmap</span>
<span id="L210" class="LineNr">210 </span> bb/copy-to-ebx 0/imm32
<span id="L211" class="LineNr">211 </span> 8a/byte-> *esi 3/r32/BL
<span id="L212" class="LineNr">212 </span> (<a href='103glyph.subx.html#L290'>draw-run-of-pixels-from-glyph</a> *(ebp+8) %ebx *(ebp+0x10) %edx *(ebp+0x18) *(ebp+0x1c) *(ebp+0x20) *(ebp+0x24) *(ebp+0x28))
<span id="L213" class="LineNr">213 </span> <span class="subxComment"># ++y</span>
<span id="L214" class="LineNr">214 </span> 42/increment-edx
<span id="L215" class="LineNr">215 </span> <span class="subxComment"># next bitmap row</span>
<span id="L216" class="LineNr">216 </span> 46/increment-esi
<span id="L217" class="LineNr">217 </span> <span class="subxComment">#</span>
<span id="L218" class="LineNr">218 </span> e9/jump <span class="Constant">loop</span>/disp32
<span id="L219" class="LineNr">219 </span> }
<span id="L220" class="LineNr">220 </span><span class="Constant">$draw-narrow-code-point-on-screen-buffer:end</span>:
<span id="L221" class="LineNr">221 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L222" class="LineNr">222 </span> 5f/pop-to-edi
<span id="L223" class="LineNr">223 </span> 5e/pop-to-esi
<span id="L224" class="LineNr">224 </span> 5b/pop-to-ebx
<span id="L225" class="LineNr">225 </span> 5a/pop-to-edx
<span id="L226" class="LineNr">226 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L227" class="LineNr">227 </span> 89/<- %esp 5/r32/ebp
<span id="L228" class="LineNr">228 </span> 5d/pop-to-ebp
<span id="L229" class="LineNr">229 </span> c3/return
<span id="L230" class="LineNr">230 </span>
<span id="L231" class="LineNr">231 </span><span class="subxComment"># buffer: naked address to raw screen RAM without a length</span>
<span id="L232" class="LineNr">232 </span><span class="subxComment"># letter-bitmap: naked address to 16-pixel wide font glyph</span>
<span id="L233" class="LineNr">233 </span><span class="subxFunction">draw-wide-code-point-on-screen-buffer</span>: <span class="subxComment"># buffer: (addr byte), letter-bitmap: (addr byte), x: int, y: int, color: int, background-color: int, overlay?: boolean, screen-width: int, screen-height: int</span>
<span id="L234" class="LineNr">234 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L235" class="LineNr">235 </span> 55/push-ebp
<span id="L236" class="LineNr">236 </span> 89/<- %ebp 4/r32/esp
<span id="L237" class="LineNr">237 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L238" class="LineNr">238 </span> 50/push-eax
<span id="L239" class="LineNr">239 </span> 51/push-ecx
<span id="L240" class="LineNr">240 </span> 52/push-edx
<span id="L241" class="LineNr">241 </span> 53/push-ebx
<span id="L242" class="LineNr">242 </span> 56/push-esi
<span id="L243" class="LineNr">243 </span> 57/push-edi
<span id="L244" class="LineNr">244 </span> <span class="subxComment"># esi = letter-bitmap</span>
<span id="L245" class="LineNr">245 </span> 8b/-> *(ebp+0xc) 6/r32/esi
<span id="L246" class="LineNr">246 </span> <span class="subxComment">#</span>
<span id="L247" class="LineNr">247 </span> bb/copy-to-ebx 0/imm32
<span id="L248" class="LineNr">248 </span> <span class="subxComment"># var ycurr/edx: int = y*16</span>
<span id="L249" class="LineNr">249 </span> 8b/-> *(ebp+0x14) 2/r32/edx
<span id="L250" class="LineNr">250 </span> c1 4/subop/shift-left %edx 4/imm8
<span id="L251" class="LineNr">251 </span> <span class="subxComment"># var ymax/edi: int = ycurr + 16</span>
<span id="L252" class="LineNr">252 </span> 8b/-> *(ebp+0x14) 7/r32/edi
<span id="L253" class="LineNr">253 </span> c1 4/subop/shift-left %edi 4/imm8
<span id="L254" class="LineNr">254 </span> 81 0/subop/add %edi 0x10/imm32
<span id="L255" class="LineNr">255 </span> {
<span id="L256" class="LineNr">256 </span> <span class="subxComment"># if (ycurr >= ymax) break</span>
<span id="L257" class="LineNr">257 </span> 39/compare %edx 7/r32/edi
<span id="L258" class="LineNr">258 </span> 0f 8d/jump-if->= <span class="Constant">break</span>/disp32
<span id="L259" class="LineNr">259 </span> <span class="subxComment"># var row-bitmap/ebx: byte = *letter-bitmap</span>
<span id="L260" class="LineNr">260 </span> 8a/byte-> *esi 3/r32/BL
<span id="L261" class="LineNr">261 </span> <span class="subxComment"># ecx = x</span>
<span id="L262" class="LineNr">262 </span> 8b/-> *(ebp+0x10) 1/r32/ecx
<span id="L263" class="LineNr">263 </span> <span class="subxComment"># first half-row</span>
<span id="L264" class="LineNr">264 </span> (<a href='103glyph.subx.html#L290'>draw-run-of-pixels-from-glyph</a> *(ebp+8) %ebx %ecx %edx *(ebp+0x18) *(ebp+0x1c) *(ebp+0x20) *(ebp+0x24) *(ebp+0x28))
<span id="L265" class="LineNr">265 </span> <span class="subxComment"># second half-row</span>
<span id="L266" class="LineNr">266 </span> 8a/byte-> *(esi+1) 3/r32/BL
<span id="L267" class="LineNr">267 </span> 41/increment-ecx
<span id="L268" class="LineNr">268 </span> (<a href='103glyph.subx.html#L290'>draw-run-of-pixels-from-glyph</a> *(ebp+8) %ebx %ecx %edx *(ebp+0x18) *(ebp+0x1c) *(ebp+0x20) *(ebp+0x24) *(ebp+0x28))
<span id="L269" class="LineNr">269 </span> <span class="subxComment"># ++y</span>
<span id="L270" class="LineNr">270 </span> 42/increment-edx
<span id="L271" class="LineNr">271 </span> <span class="subxComment"># next bitmap row</span>
<span id="L272" class="LineNr">272 </span> 81 0/subop/add %esi 2/imm32
<span id="L273" class="LineNr">273 </span> <span class="subxComment">#</span>
<span id="L274" class="LineNr">274 </span> e9/jump <span class="Constant">loop</span>/disp32
<span id="L275" class="LineNr">275 </span> }
<span id="L276" class="LineNr">276 </span><span class="Constant">$draw-wide-code-point-on-screen-buffer:end</span>:
<span id="L277" class="LineNr">277 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L278" class="LineNr">278 </span> 5f/pop-to-edi
<span id="L279" class="LineNr">279 </span> 5e/pop-to-esi
<span id="L280" class="LineNr">280 </span> 5b/pop-to-ebx
<span id="L281" class="LineNr">281 </span> 5a/pop-to-edx
<span id="L282" class="LineNr">282 </span> 59/pop-to-ecx
<span id="L283" class="LineNr">283 </span> 58/pop-to-eax
<span id="L284" class="LineNr">284 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L285" class="LineNr">285 </span> 89/<- %esp 5/r32/ebp
<span id="L286" class="LineNr">286 </span> 5d/pop-to-ebp
<span id="L287" class="LineNr">287 </span> c3/return
<span id="L288" class="LineNr">288 </span>
<span id="L289" class="LineNr">289 </span><span class="subxComment"># draw 8 pixels from a single glyph byte in a font bitmap</span>
<span id="L290" class="LineNr">290 </span><span class="subxFunction">draw-run-of-pixels-from-glyph</span>: <span class="subxComment"># buffer: (addr byte), glyph-byte: byte, x: int, y: int, color: int, background-color: int, overlay?: boolean, screen-width: int, screen-height: int</span>
<span id="L291" class="LineNr">291 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L292" class="LineNr">292 </span> 55/push-ebp
<span id="L293" class="LineNr">293 </span> 89/<- %ebp 4/r32/esp
<span id="L294" class="LineNr">294 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L295" class="LineNr">295 </span> 50/push-eax
<span id="L296" class="LineNr">296 </span> 51/push-ecx
<span id="L297" class="LineNr">297 </span> 56/push-esi
<span id="L298" class="LineNr">298 </span> <span class="subxComment"># esi = glyph-byte</span>
<span id="L299" class="LineNr">299 </span> 8b/-> *(ebp+0xc) 6/r32/esi
<span id="L300" class="LineNr">300 </span> <span class="subxComment"># var xcurr/eax: int = x*8 + 7</span>
<span id="L301" class="LineNr">301 </span> 8b/-> *(ebp+0x10) 0/r32/eax
<span id="L302" class="LineNr">302 </span> c1 4/subop/shift-left %eax 3/imm8
<span id="L303" class="LineNr">303 </span> 05/add-to-eax 7/imm32
<span id="L304" class="LineNr">304 </span> <span class="subxComment"># var xmin/ecx: int = x*8</span>
<span id="L305" class="LineNr">305 </span> 8b/-> *(ebp+0x10) 1/r32/ecx
<span id="L306" class="LineNr">306 </span> c1 4/subop/shift-left %ecx 3/imm8
<span id="L307" class="LineNr">307 </span> {
<span id="L308" class="LineNr">308 </span> <span class="subxComment"># if (xcurr < xmin) break</span>
<span id="L309" class="LineNr">309 </span> 39/compare %eax 1/r32/ecx
<span id="L310" class="LineNr">310 </span> 7c/jump-if-< <span class="Constant">break</span>/disp8
<span id="L311" class="LineNr">311 </span> <span class="subxComment"># shift LSB from row-bitmap into carry flag (CF)</span>
<span id="L312" class="LineNr">312 </span> c1 5/subop/shift-right-logical %esi 1/imm8
<span id="L313" class="LineNr">313 </span> <span class="subxComment"># if LSB, draw a pixel in the given color</span>
<span id="L314" class="LineNr">314 </span> {
<span id="L315" class="LineNr">315 </span> 73/jump-if-not-CF <span class="Constant">break</span>/disp8
<span id="L316" class="LineNr">316 </span> (<a href='101screen.subx.html#L21'>pixel-on-screen-buffer</a> *(ebp+8) %eax *(ebp+0x14) *(ebp+0x18) *(ebp+0x24) *(ebp+0x28))
<span id="L317" class="LineNr">317 </span> eb/jump $draw-code-point-on-screen-buffer:continue/disp8
<span id="L318" class="LineNr">318 </span> }
<span id="L319" class="LineNr">319 </span> <span class="subxComment"># otherwise use the background color (except when overlay?)</span>
<span id="L320" class="LineNr">320 </span> {
<span id="L321" class="LineNr">321 </span> 81 7/subop/compare *(ebp+0x20) 0/imm32/false
<span id="L322" class="LineNr">322 </span> 75/jump-if-!= <span class="Constant">break</span>/disp8
<span id="L323" class="LineNr">323 </span> (<a href='101screen.subx.html#L21'>pixel-on-screen-buffer</a> *(ebp+8) %eax *(ebp+0x14) *(ebp+0x1c) *(ebp+0x24) *(ebp+0x28))
<span id="L324" class="LineNr">324 </span> }
<span id="L325" class="LineNr">325 </span><span class="Constant">$draw-code-point-on-screen-buffer:continue</span>:
<span id="L326" class="LineNr">326 </span> <span class="subxComment"># --x</span>
<span id="L327" class="LineNr">327 </span> 48/decrement-eax
<span id="L328" class="LineNr">328 </span> <span class="subxComment">#</span>
<span id="L329" class="LineNr">329 </span> eb/jump <span class="Constant">loop</span>/disp8
<span id="L330" class="LineNr">330 </span> }
<span id="L331" class="LineNr">331 </span><span class="Constant">$draw-run-of-pixels-from-glyph:end</span>:
<span id="L332" class="LineNr">332 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L333" class="LineNr">333 </span> 5e/pop-to-esi
<span id="L334" class="LineNr">334 </span> 59/pop-to-ecx
<span id="L335" class="LineNr">335 </span> 58/pop-to-eax
<span id="L336" class="LineNr">336 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L337" class="LineNr">337 </span> 89/<- %esp 5/r32/ebp
<span id="L338" class="LineNr">338 </span> 5d/pop-to-ebp
<span id="L339" class="LineNr">339 </span> c3/return
<span id="L340" class="LineNr">340 </span>
<span id="L341" class="LineNr">341 </span><span class="subxFunction">cursor-position-on-real-screen</span>: <span class="subxComment"># -> _/eax: int, _/ecx: int</span>
<span id="L342" class="LineNr">342 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L343" class="LineNr">343 </span> 55/push-ebp
<span id="L344" class="LineNr">344 </span> 89/<- %ebp 4/r32/esp
<span id="L345" class="LineNr">345 </span> <span class="subxComment"># TODO: support fake screen; we currently assume 'screen' is always 0 (real)</span>
<span id="L346" class="LineNr">346 </span> 8b/-> *<span class="SpecialChar"><a href='103glyph.subx.html#L415'>Real-screen-cursor-x</a></span> 0/r32/eax
<span id="L347" class="LineNr">347 </span> 8b/-> *<span class="SpecialChar"><a href='103glyph.subx.html#L417'>Real-screen-cursor-y</a></span> 1/r32/ecx
<span id="L348" class="LineNr">348 </span><span class="Constant">$cursor-position-on-real-screen:end</span>:
<span id="L349" class="LineNr">349 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L350" class="LineNr">350 </span> 89/<- %esp 5/r32/ebp
<span id="L351" class="LineNr">351 </span> 5d/pop-to-ebp
<span id="L352" class="LineNr">352 </span> c3/return
<span id="L353" class="LineNr">353 </span>
<span id="L354" class="LineNr">354 </span><span class="subxFunction">set-cursor-position-on-real-screen</span>: <span class="subxComment"># x: int, y: int</span>
<span id="L355" class="LineNr">355 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L356" class="LineNr">356 </span> 55/push-ebp
<span id="L357" class="LineNr">357 </span> 89/<- %ebp 4/r32/esp
<span id="L358" class="LineNr">358 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L359" class="LineNr">359 </span> 50/push-eax
<span id="L360" class="LineNr">360 </span> <span class="subxComment">#</span>
<span id="L361" class="LineNr">361 </span> 8b/-> *(ebp+8) 0/r32/eax
<span id="L362" class="LineNr">362 </span> 89/<- *<span class="SpecialChar"><a href='103glyph.subx.html#L415'>Real-screen-cursor-x</a></span> 0/r32/eax
<span id="L363" class="LineNr">363 </span> 8b/-> *(ebp+0xc) 0/r32/eax
<span id="L364" class="LineNr">364 </span> 89/<- *<span class="SpecialChar"><a href='103glyph.subx.html#L417'>Real-screen-cursor-y</a></span> 0/r32/eax
<span id="L365" class="LineNr">365 </span><span class="Constant">$set-cursor-position-on-real-screen:end</span>:
<span id="L366" class="LineNr">366 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L367" class="LineNr">367 </span> 58/pop-to-eax
<span id="L368" class="LineNr">368 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L369" class="LineNr">369 </span> 89/<- %esp 5/r32/ebp
<span id="L370" class="LineNr">370 </span> 5d/pop-to-ebp
<span id="L371" class="LineNr">371 </span> c3/return
<span id="L372" class="LineNr">372 </span>
<span id="L373" class="LineNr">373 </span><span class="subxComment"># Not a real `show-cursor` primitive:</span>
<span id="L374" class="LineNr">374 </span><span class="subxComment"># - does not clear previous location cursor was shown at.</span>
<span id="L375" class="LineNr">375 </span><span class="subxComment"># - does not preserve what was at the cursor. Caller is responsible for</span>
<span id="L376" class="LineNr">376 </span><span class="subxComment"># tracking what was on the screen at this position before and passing it</span>
<span id="L377" class="LineNr">377 </span><span class="subxComment"># in again.</span>
<span id="L378" class="LineNr">378 </span><span class="subxComment"># - does not stop showing the cursor at this location when the cursor moves</span>
<span id="L379" class="LineNr">379 </span><span class="subxFunction">draw-cursor-on-real-screen</span>: <span class="subxComment"># c: code-point</span>
<span id="L380" class="LineNr">380 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L381" class="LineNr">381 </span> 55/push-ebp
<span id="L382" class="LineNr">382 </span> 89/<- %ebp 4/r32/esp
<span id="L383" class="LineNr">383 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L384" class="LineNr">384 </span> 50/push-eax
<span id="L385" class="LineNr">385 </span> 51/push-ecx
<span id="L386" class="LineNr">386 </span> <span class="subxComment">#</span>
<span id="L387" class="LineNr">387 </span> (<a href='103glyph.subx.html#L341'>cursor-position-on-real-screen</a>) <span class="subxComment"># => eax, ecx</span>
<span id="L388" class="LineNr">388 </span> (<a href='103glyph.subx.html#L19'>draw-code-point-on-real-screen</a> *(ebp+8) %eax %ecx 0 7) <span class="subxComment"># => eax</span>
<span id="L389" class="LineNr">389 </span><span class="Constant">$draw-cursor-on-real-screen:end</span>:
<span id="L390" class="LineNr">390 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L391" class="LineNr">391 </span> 59/pop-to-ecx
<span id="L392" class="LineNr">392 </span> 58/pop-to-eax
<span id="L393" class="LineNr">393 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L394" class="LineNr">394 </span> 89/<- %esp 5/r32/ebp
<span id="L395" class="LineNr">395 </span> 5d/pop-to-ebp
<span id="L396" class="LineNr">396 </span> c3/return
<span id="L397" class="LineNr">397 </span>
<span id="L398" class="LineNr">398 </span>== data
<span id="L399" class="LineNr">399 </span>
<span id="L400" class="LineNr">400 </span><span class="subxComment"># The cursor is where certain Mu functions (usually of the form</span>
<span id="L401" class="LineNr">401 </span><span class="subxComment"># 'draw*cursor*') print to by default.</span>
<span id="L402" class="LineNr">402 </span><span class="subxComment">#</span>
<span id="L403" class="LineNr">403 </span><span class="subxComment"># We don't bother displaying the cursor when drawing. It only becomes visible</span>
<span id="L404" class="LineNr">404 </span><span class="subxComment"># on draw-cursor, which is quite rickety (see above)</span>
<span id="L405" class="LineNr">405 </span><span class="subxComment">#</span>
<span id="L406" class="LineNr">406 </span><span class="subxComment"># It's up to applications to manage cursor display:</span>
<span id="L407" class="LineNr">407 </span><span class="subxComment"># - clean up where it used to be</span>
<span id="L408" class="LineNr">408 </span><span class="subxComment"># - display the cursor before waiting for a key</span>
<span id="L409" class="LineNr">409 </span><span class="subxComment"># - ensure its location appropriately suggests the effect keystrokes will have</span>
<span id="L410" class="LineNr">410 </span><span class="subxComment"># - ensure its contents (and colors) appropriately reflect the state of the</span>
<span id="L411" class="LineNr">411 </span><span class="subxComment"># screen</span>
<span id="L412" class="LineNr">412 </span><span class="subxComment">#</span>
<span id="L413" class="LineNr">413 </span><span class="subxComment"># There's no blinking, etc. We aren't using any hardware-supported text mode</span>
<span id="L414" class="LineNr">414 </span><span class="subxComment"># here.</span>
<span id="L415" class="LineNr">415 </span><span class="SpecialChar">Real-screen-cursor-x</span>:
<span id="L416" class="LineNr">416 </span> 0/imm32
<span id="L417" class="LineNr">417 </span><span class="SpecialChar">Real-screen-cursor-y</span>:
<span id="L418" class="LineNr">418 </span> 0/imm32
</pre>
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