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Our first buffer overflow!
This commit is contained in:
Kartik Agaram 2018-12-10 00:16:23 -08:00
parent dd08c9e69b
commit 3a4d870730
6 changed files with 319 additions and 213 deletions
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@ -100,219 +100,272 @@ if ('onhashchange' in window) {
<span id="L34" class="LineNr"> 34 </span><span class="subxComment"># main:</span>
<span id="L35" class="LineNr"> 35 </span> e8/call run-tests/disp32 <span class="subxComment"># 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'.</span>
<span id="L36" class="LineNr"> 36 </span><span class="CommentedCode">#? e8/call test-read-byte-multiple/disp32</span>
<span id="L37" class="LineNr"> 37 </span> <span class="subxComment"># syscall(exit, Num-test-failures)</span>
<span id="L38" class="LineNr"> 38 </span> 8b/copy 0/mod/indirect 5/rm32/.disp32 <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 3/r32/EBX <span class="SpecialChar">Num-test-failures</span>/disp32 <span class="subxComment"># copy *Num-test-failures to EBX</span>
<span id="L39" class="LineNr"> 39 </span> b8/copy-to-EAX 1/imm32
<span id="L40" class="LineNr"> 40 </span> cd/syscall 0x80/imm8
<span id="L41" class="LineNr"> 41 </span>
<span id="L42" class="LineNr"> 42 </span><span class="subxComment"># return next byte value in EAX, with top 3 bytes cleared.</span>
<span id="L43" class="LineNr"> 43 </span><span class="subxComment"># On EOF, return 0xffffffff.</span>
<span id="L44" class="LineNr"> 44 </span><span class="subxFunction">read-byte</span>: <span class="subxComment"># f : (address buffered-file) -&gt; byte-or-eof/EAX</span>
<span id="L45" class="LineNr"> 45 </span> <span class="subxS1Comment"># . prolog</span>
<span id="L46" class="LineNr"> 46 </span> 55/push-EBP
<span id="L47" class="LineNr"> 47 </span> 89/copy 3/mod/direct 5/rm32/EBP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/r32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="subxComment"># copy ESP to EBP</span>
<span id="L48" class="LineNr"> 48 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L49" class="LineNr"> 49 </span> 51/push-ECX
<span id="L50" class="LineNr"> 50 </span> 56/push-ESI
<span id="L51" class="LineNr"> 51 </span> <span class="subxComment"># ESI = f</span>
<span id="L52" class="LineNr"> 52 </span> 8b/copy 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none <span class="CommentedCode"> . </span> 6/r32/ESI 8/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># copy *(EBP+8) to ESI</span>
<span id="L53" class="LineNr"> 53 </span> <span class="subxComment"># ECX = f-&gt;read</span>
<span id="L54" class="LineNr"> 54 </span> 8b/copy 1/mod/*+disp8 6/rm32/ESI <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 1/r32/ECX 8/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># copy *(ESI+8) to ECX</span>
<span id="L55" class="LineNr"> 55 </span> <span class="subxComment"># if (f-&gt;read &gt;= f-&gt;write) populate stream from file</span>
<span id="L56" class="LineNr"> 56 </span> 3b/compare 1/mod/*+disp8 6/rm32/ESI <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 1/r32/ECX 4/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># compare ECX with *(ESI+4)</span>
<span id="L57" class="LineNr"> 57 </span> 7c/jump-if-lesser $read-byte:from-stream/disp8
<span id="L58" class="LineNr"> 58 </span> <span class="subxS1Comment"># . clear-stream(stream = f+4)</span>
<span id="L59" class="LineNr"> 59 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L60" class="LineNr"> 60 </span> 8d/copy-address 1/mod/*+disp8 6/rm32/ESI <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0/r32/EAX 4/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># copy ESI+4 to EAX</span>
<span id="L61" class="LineNr"> 61 </span> 50/push-EAX
<span id="L62" class="LineNr"> 62 </span> <span class="subxS2Comment"># . . call</span>
<span id="L63" class="LineNr"> 63 </span> e8/call clear-stream/disp32
<span id="L64" class="LineNr"> 64 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L65" class="LineNr"> 65 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L66" class="LineNr"> 66 </span> <span class="subxS1Comment"># . EAX = read(f-&gt;fd, stream = f+4)</span>
<span id="L67" class="LineNr"> 67 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L68" class="LineNr"> 68 </span> 50/push-EAX
<span id="L69" class="LineNr"> 69 </span> ff 6/subop/push 0/mod/indirect 6/rm32/ESI <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="subxComment"># push *ESI</span>
<span id="L70" class="LineNr"> 70 </span> <span class="subxS2Comment"># . . call</span>
<span id="L71" class="LineNr"> 71 </span> e8/call read/disp32
<span id="L72" class="LineNr"> 72 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L73" class="LineNr"> 73 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 8/imm32 <span class="subxComment"># add to ESP</span>
<span id="L74" class="LineNr"> 74 </span> <span class="subxComment"># if EAX = 0 return 0xffffffff</span>
<span id="L75" class="LineNr"> 75 </span> 81 7/subop/compare 3/mod/direct 0/rm32/EAX <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0/imm32 <span class="subxComment"># compare EAX</span>
<span id="L76" class="LineNr"> 76 </span> 75/jump-if-not-equal $read-byte:from-stream/disp8
<span id="L77" class="LineNr"> 77 </span> b8/copy-to-EAX 0xffffffff/imm32
<span id="L78" class="LineNr"> 78 </span> eb/jump $read-byte:end/disp8
<span id="L79" class="LineNr"> 79 </span><span class="Constant">$read-byte:from-stream</span>:
<span id="L80" class="LineNr"> 80 </span> <span class="subxComment"># read byte from stream</span>
<span id="L81" class="LineNr"> 81 </span> <span class="subxComment"># AL = f-&gt;data[f-&gt;read]</span>
<span id="L82" class="LineNr"> 82 </span> 31/xor 3/mod/direct 0/rm32/EAX <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0/r32/EAX <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="subxComment"># clear EAX</span>
<span id="L83" class="LineNr"> 83 </span> 8a/copy-byte 1/mod/*+disp8 4/rm32/sib 6/base/ESI 1/index/ECX <span class="CommentedCode"> . </span> 0/r32/AL 0x10/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># copy byte at *(ESI+ECX+16) to AL</span>
<span id="L84" class="LineNr"> 84 </span> <span class="subxComment"># ++f-&gt;read</span>
<span id="L85" class="LineNr"> 85 </span> ff 0/subop/increment 1/mod/*+disp8 6/rm32/ESI <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 8/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># increment *(ESI+8)</span>
<span id="L86" class="LineNr"> 86 </span><span class="Constant">$read-byte:end</span>:
<span id="L87" class="LineNr"> 87 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L88" class="LineNr"> 88 </span> 5e/pop-to-ESI
<span id="L89" class="LineNr"> 89 </span> 59/pop-to-ECX
<span id="L90" class="LineNr"> 90 </span> <span class="subxS1Comment"># . epilog</span>
<span id="L91" class="LineNr"> 91 </span> 89/copy 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 5/r32/EBP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="subxComment"># copy EBP to ESP</span>
<span id="L92" class="LineNr"> 92 </span> 5d/pop-to-EBP
<span id="L93" class="LineNr"> 93 </span> c3/return
<span id="L94" class="LineNr"> 94 </span>
<span id="L95" class="LineNr"> 95 </span><span class="subxH1Comment"># - tests</span>
<span id="L96" class="LineNr"> 96 </span>
<span id="L97" class="LineNr"> 97 </span><span class="subxTest">test-read-byte-single</span>:
<span id="L98" class="LineNr"> 98 </span> <span class="subxH1Comment"># - check that read-byte returns first byte of 'file'</span>
<span id="L99" class="LineNr"> 99 </span> <span class="subxComment"># setup</span>
<span id="L100" class="LineNr">100 </span> <span class="subxS1Comment"># . clear-stream(_test-stream)</span>
<span id="L101" class="LineNr">101 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L102" class="LineNr">102 </span> 68/push _test-stream/imm32
<span id="L103" class="LineNr">103 </span> <span class="subxS2Comment"># . . call</span>
<span id="L104" class="LineNr">104 </span> e8/call clear-stream/disp32
<span id="L105" class="LineNr">105 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L106" class="LineNr">106 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L107" class="LineNr">107 </span> <span class="subxS1Comment"># . clear-stream(_test-buffered-file+4)</span>
<span id="L108" class="LineNr">108 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L109" class="LineNr">109 </span> b8/copy-to-EAX _test-buffered-file/imm32
<span id="L110" class="LineNr">110 </span> 05/add-to-EAX 4/imm32
<span id="L111" class="LineNr">111 </span> 50/push-EAX
<span id="L112" class="LineNr">112 </span> <span class="subxS2Comment"># . . call</span>
<span id="L113" class="LineNr">113 </span> e8/call clear-stream/disp32
<span id="L114" class="LineNr">114 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L115" class="LineNr">115 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L116" class="LineNr">116 </span> <span class="subxS1Comment"># . write(_test-stream, &quot;Ab&quot;)</span>
<span id="L117" class="LineNr">117 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L118" class="LineNr">118 </span> 68/push <span class="Constant">&quot;Ab&quot;</span>/imm32
<span id="L119" class="LineNr">119 </span> 68/push _test-stream/imm32
<span id="L120" class="LineNr">120 </span> <span class="subxS2Comment"># . . call</span>
<span id="L121" class="LineNr">121 </span> e8/call write/disp32
<span id="L122" class="LineNr">122 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L123" class="LineNr">123 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 8/imm32 <span class="subxComment"># add to ESP</span>
<span id="L124" class="LineNr">124 </span> <span class="subxComment"># read-byte(_test-buffered-file)</span>
<span id="L125" class="LineNr">125 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L126" class="LineNr">126 </span> 68/push _test-buffered-file/imm32
<span id="L127" class="LineNr">127 </span> <span class="subxS2Comment"># . . call</span>
<span id="L128" class="LineNr">128 </span> e8/call read-byte/disp32
<span id="L129" class="LineNr">129 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L130" class="LineNr">130 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L131" class="LineNr">131 </span> <span class="subxComment"># check-ints-equal(EAX, 'A', msg)</span>
<span id="L132" class="LineNr">132 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L133" class="LineNr">133 </span> 68/push <span class="Constant">&quot;F - test-read-byte-single&quot;</span>/imm32
<span id="L134" class="LineNr">134 </span> 68/push 0x41/imm32
<span id="L135" class="LineNr">135 </span> 50/push-EAX
<span id="L136" class="LineNr">136 </span> <span class="subxS2Comment"># . . call</span>
<span id="L137" class="LineNr">137 </span> e8/call check-ints-equal/disp32
<span id="L138" class="LineNr">138 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L139" class="LineNr">139 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0xc/imm32 <span class="subxComment"># add to ESP</span>
<span id="L140" class="LineNr">140 </span> <span class="subxS1Comment"># . end</span>
<span id="L141" class="LineNr">141 </span> c3/return
<span id="L142" class="LineNr">142 </span>
<span id="L143" class="LineNr">143 </span><span class="subxTest">test-read-byte-multiple</span>:
<span id="L144" class="LineNr">144 </span> <span class="subxH1Comment"># - call read-byte twice, check that second call returns second byte</span>
<span id="L145" class="LineNr">145 </span> <span class="subxComment"># setup</span>
<span id="L146" class="LineNr">146 </span> <span class="subxS1Comment"># . clear-stream(_test-stream)</span>
<span id="L147" class="LineNr">147 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L148" class="LineNr">148 </span> 68/push _test-stream/imm32
<span id="L149" class="LineNr">149 </span> <span class="subxS2Comment"># . . call</span>
<span id="L150" class="LineNr">150 </span> e8/call clear-stream/disp32
<span id="L151" class="LineNr">151 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L152" class="LineNr">152 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L153" class="LineNr">153 </span> <span class="subxS1Comment"># . clear-stream(_test-buffered-file+4)</span>
<span id="L154" class="LineNr">154 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L155" class="LineNr">155 </span> b8/copy-to-EAX _test-buffered-file/imm32
<span id="L156" class="LineNr">156 </span> 05/add-to-EAX 4/imm32
<span id="L157" class="LineNr">157 </span> 50/push-EAX
<span id="L158" class="LineNr">158 </span> <span class="subxS2Comment"># . . call</span>
<span id="L159" class="LineNr">159 </span> e8/call clear-stream/disp32
<span id="L160" class="LineNr">160 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L161" class="LineNr">161 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L162" class="LineNr">162 </span> <span class="subxS1Comment"># . write(_test-stream, &quot;Ab&quot;)</span>
<span id="L163" class="LineNr">163 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L164" class="LineNr">164 </span> 68/push <span class="Constant">&quot;Ab&quot;</span>/imm32
<span id="L165" class="LineNr">165 </span> 68/push _test-stream/imm32
<span id="L166" class="LineNr">166 </span> <span class="subxS2Comment"># . . call</span>
<span id="L167" class="LineNr">167 </span> e8/call write/disp32
<span id="L168" class="LineNr">168 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L169" class="LineNr">169 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 8/imm32 <span class="subxComment"># add to ESP</span>
<span id="L170" class="LineNr">170 </span> <span class="subxComment"># read-byte(_test-buffered-file)</span>
<span id="L171" class="LineNr">171 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L172" class="LineNr">172 </span> 68/push _test-buffered-file/imm32
<span id="L173" class="LineNr">173 </span> <span class="subxS2Comment"># . . call</span>
<span id="L174" class="LineNr">174 </span> e8/call read-byte/disp32
<span id="L175" class="LineNr">175 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L176" class="LineNr">176 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L177" class="LineNr">177 </span> <span class="subxComment"># read-byte(_test-buffered-file)</span>
<span id="L178" class="LineNr">178 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L179" class="LineNr">179 </span> 68/push _test-buffered-file/imm32
<span id="L180" class="LineNr">180 </span> <span class="subxS2Comment"># . . call</span>
<span id="L181" class="LineNr">181 </span> e8/call read-byte/disp32
<span id="L182" class="LineNr">182 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L183" class="LineNr">183 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L184" class="LineNr">184 </span> <span class="subxComment"># check-ints-equal(EAX, 'b', msg)</span>
<span id="L185" class="LineNr">185 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L186" class="LineNr">186 </span> 68/push <span class="Constant">&quot;F - test-read-byte-multiple&quot;</span>/imm32
<span id="L187" class="LineNr">187 </span> 68/push 0x62/imm32
<span id="L188" class="LineNr">188 </span> 50/push-EAX
<span id="L189" class="LineNr">189 </span> <span class="subxS2Comment"># . . call</span>
<span id="L190" class="LineNr">190 </span> e8/call check-ints-equal/disp32
<span id="L191" class="LineNr">191 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L192" class="LineNr">192 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0xc/imm32 <span class="subxComment"># add to ESP</span>
<span id="L193" class="LineNr">193 </span> <span class="subxS1Comment"># . end</span>
<span id="L194" class="LineNr">194 </span> c3/return
<span id="L195" class="LineNr">195 </span>
<span id="L196" class="LineNr">196 </span><span class="subxTest">test-read-byte-end-of-file</span>:
<span id="L197" class="LineNr">197 </span> <span class="subxH1Comment"># - call read-byte on an empty 'file', check that it returns 0xffffffff</span>
<span id="L198" class="LineNr">198 </span> <span class="subxComment"># setup</span>
<span id="L199" class="LineNr">199 </span> <span class="subxS1Comment"># . clear-stream(_test-stream)</span>
<span id="L200" class="LineNr">200 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L201" class="LineNr">201 </span> 68/push _test-stream/imm32
<span id="L202" class="LineNr">202 </span> <span class="subxS2Comment"># . . call</span>
<span id="L203" class="LineNr">203 </span> e8/call clear-stream/disp32
<span id="L204" class="LineNr">204 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L205" class="LineNr">205 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L206" class="LineNr">206 </span> <span class="subxS1Comment"># . clear-stream(_test-buffered-file+4)</span>
<span id="L207" class="LineNr">207 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L208" class="LineNr">208 </span> b8/copy-to-EAX _test-buffered-file/imm32
<span id="L209" class="LineNr">209 </span> 05/add-to-EAX 4/imm32
<span id="L210" class="LineNr">210 </span> 50/push-EAX
<span id="L211" class="LineNr">211 </span> <span class="subxS2Comment"># . . call</span>
<span id="L212" class="LineNr">212 </span> e8/call clear-stream/disp32
<span id="L213" class="LineNr">213 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L214" class="LineNr">214 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L215" class="LineNr">215 </span> <span class="subxComment"># read-byte(_test-buffered-file)</span>
<span id="L216" class="LineNr">216 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L217" class="LineNr">217 </span> 68/push _test-buffered-file/imm32
<span id="L218" class="LineNr">218 </span> <span class="subxS2Comment"># . . call</span>
<span id="L219" class="LineNr">219 </span> e8/call read-byte/disp32
<span id="L220" class="LineNr">220 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L221" class="LineNr">221 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L222" class="LineNr">222 </span> <span class="subxComment"># check-ints-equal(EAX, 0xffffffff, msg)</span>
<span id="L223" class="LineNr">223 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L224" class="LineNr">224 </span> 68/push <span class="Constant">&quot;F - test-read-byte-end-of-file&quot;</span>/imm32
<span id="L225" class="LineNr">225 </span> 68/push 0xffffffff/imm32
<span id="L226" class="LineNr">226 </span> 50/push-EAX
<span id="L227" class="LineNr">227 </span> <span class="subxS2Comment"># . . call</span>
<span id="L228" class="LineNr">228 </span> e8/call check-ints-equal/disp32
<span id="L229" class="LineNr">229 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L230" class="LineNr">230 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0xc/imm32 <span class="subxComment"># add to ESP</span>
<span id="L231" class="LineNr">231 </span> <span class="subxS1Comment"># . end</span>
<span id="L232" class="LineNr">232 </span> c3/return
<span id="L233" class="LineNr">233 </span>
<span id="L234" class="LineNr">234 </span>== data
<span id="L235" class="LineNr">235 </span>
<span id="L236" class="LineNr">236 </span><span class="subxComment"># a test buffered file for _test-stream</span>
<span id="L237" class="LineNr">237 </span><span class="subxMinorFunction">_test-buffered-file</span>:
<span id="L238" class="LineNr">238 </span> <span class="subxComment"># file descriptor or (address stream)</span>
<span id="L239" class="LineNr">239 </span> _test-stream/imm32
<span id="L240" class="LineNr">240 </span> <span class="subxComment"># current write index</span>
<span id="L241" class="LineNr">241 </span> 00 00 00 00
<span id="L242" class="LineNr">242 </span> <span class="subxComment"># current read index</span>
<span id="L243" class="LineNr">243 </span> 00 00 00 00
<span id="L244" class="LineNr">244 </span> <span class="subxComment"># length (6)</span>
<span id="L245" class="LineNr">245 </span> 06 00 00 00
<span id="L246" class="LineNr">246 </span> <span class="subxComment"># data</span>
<span id="L247" class="LineNr">247 </span> 00 00 00 00 00 00 <span class="subxComment"># 6 bytes</span>
<span id="L248" class="LineNr">248 </span>
<span id="L249" class="LineNr">249 </span><span class="subxS2Comment"># . . vim&#0058;nowrap:textwidth=0</span>
<span id="L37" class="LineNr"> 37 </span><span class="CommentedCode">#? e8/call test-read-byte-refills-buffer/disp32</span>
<span id="L38" class="LineNr"> 38 </span> <span class="subxComment"># syscall(exit, Num-test-failures)</span>
<span id="L39" class="LineNr"> 39 </span> 8b/copy 0/mod/indirect 5/rm32/.disp32 <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 3/r32/EBX <span class="SpecialChar">Num-test-failures</span>/disp32 <span class="subxComment"># copy *Num-test-failures to EBX</span>
<span id="L40" class="LineNr"> 40 </span> b8/copy-to-EAX 1/imm32
<span id="L41" class="LineNr"> 41 </span> cd/syscall 0x80/imm8
<span id="L42" class="LineNr"> 42 </span>
<span id="L43" class="LineNr"> 43 </span><span class="subxComment"># return next byte value in EAX, with top 3 bytes cleared.</span>
<span id="L44" class="LineNr"> 44 </span><span class="subxComment"># On EOF, return 0xffffffff.</span>
<span id="L45" class="LineNr"> 45 </span><span class="subxFunction">read-byte</span>: <span class="subxComment"># f : (address buffered-file) -&gt; byte-or-eof/EAX</span>
<span id="L46" class="LineNr"> 46 </span> <span class="subxS1Comment"># . prolog</span>
<span id="L47" class="LineNr"> 47 </span> 55/push-EBP
<span id="L48" class="LineNr"> 48 </span> 89/copy 3/mod/direct 5/rm32/EBP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/r32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="subxComment"># copy ESP to EBP</span>
<span id="L49" class="LineNr"> 49 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L50" class="LineNr"> 50 </span> 51/push-ECX
<span id="L51" class="LineNr"> 51 </span> 56/push-ESI
<span id="L52" class="LineNr"> 52 </span> <span class="subxComment"># ESI = f</span>
<span id="L53" class="LineNr"> 53 </span> 8b/copy 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none <span class="CommentedCode"> . </span> 6/r32/ESI 8/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># copy *(EBP+8) to ESI</span>
<span id="L54" class="LineNr"> 54 </span> <span class="subxComment"># ECX = f-&gt;read</span>
<span id="L55" class="LineNr"> 55 </span> 8b/copy 1/mod/*+disp8 6/rm32/ESI <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 1/r32/ECX 8/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># copy *(ESI+8) to ECX</span>
<span id="L56" class="LineNr"> 56 </span> <span class="subxComment"># if (f-&gt;read &gt;= f-&gt;write) populate stream from file</span>
<span id="L57" class="LineNr"> 57 </span> 3b/compare 1/mod/*+disp8 6/rm32/ESI <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 1/r32/ECX 4/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># compare ECX with *(ESI+4)</span>
<span id="L58" class="LineNr"> 58 </span> 7c/jump-if-lesser $read-byte:from-stream/disp8
<span id="L59" class="LineNr"> 59 </span> <span class="subxS1Comment"># . clear-stream(stream = f+4)</span>
<span id="L60" class="LineNr"> 60 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L61" class="LineNr"> 61 </span> 8d/copy-address 1/mod/*+disp8 6/rm32/ESI <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0/r32/EAX 4/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># copy ESI+4 to EAX</span>
<span id="L62" class="LineNr"> 62 </span> 50/push-EAX
<span id="L63" class="LineNr"> 63 </span> <span class="subxS2Comment"># . . call</span>
<span id="L64" class="LineNr"> 64 </span> e8/call clear-stream/disp32
<span id="L65" class="LineNr"> 65 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L66" class="LineNr"> 66 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L67" class="LineNr"> 67 </span> <span class="subxS1Comment"># . f-&gt;read must now be 0; update ECX</span>
<span id="L68" class="LineNr"> 68 </span> 31/xor 3/mod/direct 1/rm32/ECX <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 1/r32/ECX <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="subxComment"># clear ECX</span>
<span id="L69" class="LineNr"> 69 </span> <span class="subxS1Comment"># . EAX = read(f-&gt;fd, stream = f+4)</span>
<span id="L70" class="LineNr"> 70 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L71" class="LineNr"> 71 </span> 50/push-EAX
<span id="L72" class="LineNr"> 72 </span> ff 6/subop/push 0/mod/indirect 6/rm32/ESI <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="subxComment"># push *ESI</span>
<span id="L73" class="LineNr"> 73 </span> <span class="subxS2Comment"># . . call</span>
<span id="L74" class="LineNr"> 74 </span> e8/call read/disp32
<span id="L75" class="LineNr"> 75 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L76" class="LineNr"> 76 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 8/imm32 <span class="subxComment"># add to ESP</span>
<span id="L77" class="LineNr"> 77 </span> <span class="subxComment"># if EAX = 0 return 0xffffffff</span>
<span id="L78" class="LineNr"> 78 </span> 81 7/subop/compare 3/mod/direct 0/rm32/EAX <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0/imm32 <span class="subxComment"># compare EAX</span>
<span id="L79" class="LineNr"> 79 </span> 75/jump-if-not-equal $read-byte:from-stream/disp8
<span id="L80" class="LineNr"> 80 </span> b8/copy-to-EAX 0xffffffff/imm32
<span id="L81" class="LineNr"> 81 </span> eb/jump $read-byte:end/disp8
<span id="L82" class="LineNr"> 82 </span><span class="Constant">$read-byte:from-stream</span>:
<span id="L83" class="LineNr"> 83 </span> <span class="subxComment"># read byte from stream</span>
<span id="L84" class="LineNr"> 84 </span> <span class="subxComment"># AL = f-&gt;data[f-&gt;read]</span>
<span id="L85" class="LineNr"> 85 </span> 31/xor 3/mod/direct 0/rm32/EAX <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0/r32/EAX <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="subxComment"># clear EAX</span>
<span id="L86" class="LineNr"> 86 </span> 8a/copy-byte 1/mod/*+disp8 4/rm32/sib 6/base/ESI 1/index/ECX <span class="CommentedCode"> . </span> 0/r32/AL 0x10/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># copy byte at *(ESI+ECX+16) to AL</span>
<span id="L87" class="LineNr"> 87 </span> <span class="subxComment"># ++f-&gt;read</span>
<span id="L88" class="LineNr"> 88 </span> ff 0/subop/increment 1/mod/*+disp8 6/rm32/ESI <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 8/disp8 <span class="CommentedCode"> . </span> <span class="subxComment"># increment *(ESI+8)</span>
<span id="L89" class="LineNr"> 89 </span><span class="Constant">$read-byte:end</span>:
<span id="L90" class="LineNr"> 90 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L91" class="LineNr"> 91 </span> 5e/pop-to-ESI
<span id="L92" class="LineNr"> 92 </span> 59/pop-to-ECX
<span id="L93" class="LineNr"> 93 </span> <span class="subxS1Comment"># . epilog</span>
<span id="L94" class="LineNr"> 94 </span> 89/copy 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 5/r32/EBP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="subxComment"># copy EBP to ESP</span>
<span id="L95" class="LineNr"> 95 </span> 5d/pop-to-EBP
<span id="L96" class="LineNr"> 96 </span> c3/return
<span id="L97" class="LineNr"> 97 </span>
<span id="L98" class="LineNr"> 98 </span><span class="subxH1Comment"># - tests</span>
<span id="L99" class="LineNr"> 99 </span>
<span id="L100" class="LineNr">100 </span><span class="subxTest">test-read-byte-single</span>:
<span id="L101" class="LineNr">101 </span> <span class="subxH1Comment"># - check that read-byte returns first byte of 'file'</span>
<span id="L102" class="LineNr">102 </span> <span class="subxComment"># setup</span>
<span id="L103" class="LineNr">103 </span> <span class="subxS1Comment"># . clear-stream(_test-stream)</span>
<span id="L104" class="LineNr">104 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L105" class="LineNr">105 </span> 68/push _test-stream/imm32
<span id="L106" class="LineNr">106 </span> <span class="subxS2Comment"># . . call</span>
<span id="L107" class="LineNr">107 </span> e8/call clear-stream/disp32
<span id="L108" class="LineNr">108 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L109" class="LineNr">109 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L110" class="LineNr">110 </span> <span class="subxS1Comment"># . clear-stream(_test-buffered-file+4)</span>
<span id="L111" class="LineNr">111 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L112" class="LineNr">112 </span> b8/copy-to-EAX _test-buffered-file/imm32
<span id="L113" class="LineNr">113 </span> 05/add-to-EAX 4/imm32
<span id="L114" class="LineNr">114 </span> 50/push-EAX
<span id="L115" class="LineNr">115 </span> <span class="subxS2Comment"># . . call</span>
<span id="L116" class="LineNr">116 </span> e8/call clear-stream/disp32
<span id="L117" class="LineNr">117 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L118" class="LineNr">118 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L119" class="LineNr">119 </span> <span class="subxS1Comment"># . write(_test-stream, &quot;Ab&quot;)</span>
<span id="L120" class="LineNr">120 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L121" class="LineNr">121 </span> 68/push <span class="Constant">&quot;Ab&quot;</span>/imm32
<span id="L122" class="LineNr">122 </span> 68/push _test-stream/imm32
<span id="L123" class="LineNr">123 </span> <span class="subxS2Comment"># . . call</span>
<span id="L124" class="LineNr">124 </span> e8/call write/disp32
<span id="L125" class="LineNr">125 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L126" class="LineNr">126 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 8/imm32 <span class="subxComment"># add to ESP</span>
<span id="L127" class="LineNr">127 </span> <span class="subxComment"># read-byte(_test-buffered-file)</span>
<span id="L128" class="LineNr">128 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L129" class="LineNr">129 </span> 68/push _test-buffered-file/imm32
<span id="L130" class="LineNr">130 </span> <span class="subxS2Comment"># . . call</span>
<span id="L131" class="LineNr">131 </span> e8/call read-byte/disp32
<span id="L132" class="LineNr">132 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L133" class="LineNr">133 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L134" class="LineNr">134 </span> <span class="subxComment"># check-ints-equal(EAX, 'A', msg)</span>
<span id="L135" class="LineNr">135 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L136" class="LineNr">136 </span> 68/push <span class="Constant">&quot;F - test-read-byte-single&quot;</span>/imm32
<span id="L137" class="LineNr">137 </span> 68/push 0x41/imm32
<span id="L138" class="LineNr">138 </span> 50/push-EAX
<span id="L139" class="LineNr">139 </span> <span class="subxS2Comment"># . . call</span>
<span id="L140" class="LineNr">140 </span> e8/call check-ints-equal/disp32
<span id="L141" class="LineNr">141 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L142" class="LineNr">142 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0xc/imm32 <span class="subxComment"># add to ESP</span>
<span id="L143" class="LineNr">143 </span> <span class="subxS1Comment"># . end</span>
<span id="L144" class="LineNr">144 </span> c3/return
<span id="L145" class="LineNr">145 </span>
<span id="L146" class="LineNr">146 </span><span class="subxTest">test-read-byte-multiple</span>:
<span id="L147" class="LineNr">147 </span> <span class="subxH1Comment"># - call read-byte twice, check that second call returns second byte</span>
<span id="L148" class="LineNr">148 </span> <span class="subxComment"># setup</span>
<span id="L149" class="LineNr">149 </span> <span class="subxS1Comment"># . clear-stream(_test-stream)</span>
<span id="L150" class="LineNr">150 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L151" class="LineNr">151 </span> 68/push _test-stream/imm32
<span id="L152" class="LineNr">152 </span> <span class="subxS2Comment"># . . call</span>
<span id="L153" class="LineNr">153 </span> e8/call clear-stream/disp32
<span id="L154" class="LineNr">154 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L155" class="LineNr">155 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L156" class="LineNr">156 </span> <span class="subxS1Comment"># . clear-stream(_test-buffered-file+4)</span>
<span id="L157" class="LineNr">157 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L158" class="LineNr">158 </span> b8/copy-to-EAX _test-buffered-file/imm32
<span id="L159" class="LineNr">159 </span> 05/add-to-EAX 4/imm32
<span id="L160" class="LineNr">160 </span> 50/push-EAX
<span id="L161" class="LineNr">161 </span> <span class="subxS2Comment"># . . call</span>
<span id="L162" class="LineNr">162 </span> e8/call clear-stream/disp32
<span id="L163" class="LineNr">163 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L164" class="LineNr">164 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L165" class="LineNr">165 </span> <span class="subxS1Comment"># . write(_test-stream, &quot;Ab&quot;)</span>
<span id="L166" class="LineNr">166 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L167" class="LineNr">167 </span> 68/push <span class="Constant">&quot;Ab&quot;</span>/imm32
<span id="L168" class="LineNr">168 </span> 68/push _test-stream/imm32
<span id="L169" class="LineNr">169 </span> <span class="subxS2Comment"># . . call</span>
<span id="L170" class="LineNr">170 </span> e8/call write/disp32
<span id="L171" class="LineNr">171 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L172" class="LineNr">172 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 8/imm32 <span class="subxComment"># add to ESP</span>
<span id="L173" class="LineNr">173 </span> <span class="subxComment"># read-byte(_test-buffered-file)</span>
<span id="L174" class="LineNr">174 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L175" class="LineNr">175 </span> 68/push _test-buffered-file/imm32
<span id="L176" class="LineNr">176 </span> <span class="subxS2Comment"># . . call</span>
<span id="L177" class="LineNr">177 </span> e8/call read-byte/disp32
<span id="L178" class="LineNr">178 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L179" class="LineNr">179 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L180" class="LineNr">180 </span> <span class="subxComment"># read-byte(_test-buffered-file)</span>
<span id="L181" class="LineNr">181 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L182" class="LineNr">182 </span> 68/push _test-buffered-file/imm32
<span id="L183" class="LineNr">183 </span> <span class="subxS2Comment"># . . call</span>
<span id="L184" class="LineNr">184 </span> e8/call read-byte/disp32
<span id="L185" class="LineNr">185 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L186" class="LineNr">186 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L187" class="LineNr">187 </span> <span class="subxComment"># check-ints-equal(EAX, 'b', msg)</span>
<span id="L188" class="LineNr">188 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L189" class="LineNr">189 </span> 68/push <span class="Constant">&quot;F - test-read-byte-multiple&quot;</span>/imm32
<span id="L190" class="LineNr">190 </span> 68/push 0x62/imm32
<span id="L191" class="LineNr">191 </span> 50/push-EAX
<span id="L192" class="LineNr">192 </span> <span class="subxS2Comment"># . . call</span>
<span id="L193" class="LineNr">193 </span> e8/call check-ints-equal/disp32
<span id="L194" class="LineNr">194 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L195" class="LineNr">195 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0xc/imm32 <span class="subxComment"># add to ESP</span>
<span id="L196" class="LineNr">196 </span> <span class="subxS1Comment"># . end</span>
<span id="L197" class="LineNr">197 </span> c3/return
<span id="L198" class="LineNr">198 </span>
<span id="L199" class="LineNr">199 </span><span class="subxTest">test-read-byte-end-of-file</span>:
<span id="L200" class="LineNr">200 </span> <span class="subxH1Comment"># - call read-byte on an empty 'file', check that it returns 0xffffffff</span>
<span id="L201" class="LineNr">201 </span> <span class="subxComment"># setup</span>
<span id="L202" class="LineNr">202 </span> <span class="subxS1Comment"># . clear-stream(_test-stream)</span>
<span id="L203" class="LineNr">203 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L204" class="LineNr">204 </span> 68/push _test-stream/imm32
<span id="L205" class="LineNr">205 </span> <span class="subxS2Comment"># . . call</span>
<span id="L206" class="LineNr">206 </span> e8/call clear-stream/disp32
<span id="L207" class="LineNr">207 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L208" class="LineNr">208 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L209" class="LineNr">209 </span> <span class="subxS1Comment"># . clear-stream(_test-buffered-file+4)</span>
<span id="L210" class="LineNr">210 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L211" class="LineNr">211 </span> b8/copy-to-EAX _test-buffered-file/imm32
<span id="L212" class="LineNr">212 </span> 05/add-to-EAX 4/imm32
<span id="L213" class="LineNr">213 </span> 50/push-EAX
<span id="L214" class="LineNr">214 </span> <span class="subxS2Comment"># . . call</span>
<span id="L215" class="LineNr">215 </span> e8/call clear-stream/disp32
<span id="L216" class="LineNr">216 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L217" class="LineNr">217 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L218" class="LineNr">218 </span> <span class="subxComment"># read-byte(_test-buffered-file)</span>
<span id="L219" class="LineNr">219 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L220" class="LineNr">220 </span> 68/push _test-buffered-file/imm32
<span id="L221" class="LineNr">221 </span> <span class="subxS2Comment"># . . call</span>
<span id="L222" class="LineNr">222 </span> e8/call read-byte/disp32
<span id="L223" class="LineNr">223 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L224" class="LineNr">224 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L225" class="LineNr">225 </span> <span class="subxComment"># check-ints-equal(EAX, 0xffffffff, msg)</span>
<span id="L226" class="LineNr">226 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L227" class="LineNr">227 </span> 68/push <span class="Constant">&quot;F - test-read-byte-end-of-file&quot;</span>/imm32
<span id="L228" class="LineNr">228 </span> 68/push 0xffffffff/imm32
<span id="L229" class="LineNr">229 </span> 50/push-EAX
<span id="L230" class="LineNr">230 </span> <span class="subxS2Comment"># . . call</span>
<span id="L231" class="LineNr">231 </span> e8/call check-ints-equal/disp32
<span id="L232" class="LineNr">232 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L233" class="LineNr">233 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0xc/imm32 <span class="subxComment"># add to ESP</span>
<span id="L234" class="LineNr">234 </span> <span class="subxS1Comment"># . end</span>
<span id="L235" class="LineNr">235 </span> c3/return
<span id="L236" class="LineNr">236 </span>
<span id="L237" class="LineNr">237 </span><span class="subxTest">test-read-byte-refills-buffer</span>:
<span id="L238" class="LineNr">238 </span> <span class="subxH1Comment"># - consume buffered-file's buffer, check that next read-byte still works</span>
<span id="L239" class="LineNr">239 </span> <span class="subxComment"># setup</span>
<span id="L240" class="LineNr">240 </span> <span class="subxS1Comment"># . clear-stream(_test-stream)</span>
<span id="L241" class="LineNr">241 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L242" class="LineNr">242 </span> 68/push _test-stream/imm32
<span id="L243" class="LineNr">243 </span> <span class="subxS2Comment"># . . call</span>
<span id="L244" class="LineNr">244 </span> e8/call clear-stream/disp32
<span id="L245" class="LineNr">245 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L246" class="LineNr">246 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L247" class="LineNr">247 </span> <span class="subxS1Comment"># . clear-stream(_test-buffered-file+4)</span>
<span id="L248" class="LineNr">248 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L249" class="LineNr">249 </span> b8/copy-to-EAX _test-buffered-file/imm32
<span id="L250" class="LineNr">250 </span> 05/add-to-EAX 4/imm32
<span id="L251" class="LineNr">251 </span> 50/push-EAX
<span id="L252" class="LineNr">252 </span> <span class="subxS2Comment"># . . call</span>
<span id="L253" class="LineNr">253 </span> e8/call clear-stream/disp32
<span id="L254" class="LineNr">254 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L255" class="LineNr">255 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L256" class="LineNr">256 </span> <span class="subxS1Comment"># . write(_test-stream, &quot;Abcdefgh&quot;)</span>
<span id="L257" class="LineNr">257 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L258" class="LineNr">258 </span> 68/push <span class="Constant">&quot;Abcdefgh&quot;</span>/imm32
<span id="L259" class="LineNr">259 </span> 68/push _test-stream/imm32
<span id="L260" class="LineNr">260 </span> <span class="subxS2Comment"># . . call</span>
<span id="L261" class="LineNr">261 </span> e8/call write/disp32
<span id="L262" class="LineNr">262 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L263" class="LineNr">263 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 8/imm32 <span class="subxComment"># add to ESP</span>
<span id="L264" class="LineNr">264 </span> <span class="subxComment"># pretend buffer is full</span>
<span id="L265" class="LineNr">265 </span> <span class="subxS1Comment"># . _test-buffered-file-&gt;read = 6 # &gt;= _test-buffered-file-&gt;length</span>
<span id="L266" class="LineNr">266 </span> b8/copy-to-EAX _test-buffered-file/imm32
<span id="L267" class="LineNr">267 </span> c7/copy 1/mod/*+disp8 0/rm32/EAX <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 8/disp8 6/imm32 <span class="subxComment"># copy to *(EAX+8)</span>
<span id="L268" class="LineNr">268 </span> <span class="subxComment"># read-byte(_test-buffered-file)</span>
<span id="L269" class="LineNr">269 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L270" class="LineNr">270 </span> 68/push _test-buffered-file/imm32
<span id="L271" class="LineNr">271 </span> <span class="subxS2Comment"># . . call</span>
<span id="L272" class="LineNr">272 </span> e8/call read-byte/disp32
<span id="L273" class="LineNr">273 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L274" class="LineNr">274 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 4/imm32 <span class="subxComment"># add to ESP</span>
<span id="L275" class="LineNr">275 </span> <span class="subxComment"># check-ints-equal(EAX, 'A', msg)</span>
<span id="L276" class="LineNr">276 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L277" class="LineNr">277 </span> 68/push <span class="Constant">&quot;F - test-read-byte-refills-buffer&quot;</span>/imm32
<span id="L278" class="LineNr">278 </span> 68/push 0x41/imm32
<span id="L279" class="LineNr">279 </span> 50/push-EAX
<span id="L280" class="LineNr">280 </span> <span class="subxS2Comment"># . . call</span>
<span id="L281" class="LineNr">281 </span> e8/call check-ints-equal/disp32
<span id="L282" class="LineNr">282 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L283" class="LineNr">283 </span> 81 0/subop/add 3/mod/direct 4/rm32/ESP <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> <span class="CommentedCode"> . </span> 0xc/imm32 <span class="subxComment"># add to ESP</span>
<span id="L284" class="LineNr">284 </span> <span class="subxS1Comment"># . end</span>
<span id="L285" class="LineNr">285 </span> c3/return
<span id="L286" class="LineNr">286 </span>
<span id="L287" class="LineNr">287 </span>== data
<span id="L288" class="LineNr">288 </span>
<span id="L289" class="LineNr">289 </span><span class="subxComment"># a test buffered file for _test-stream</span>
<span id="L290" class="LineNr">290 </span><span class="subxMinorFunction">_test-buffered-file</span>:
<span id="L291" class="LineNr">291 </span> <span class="subxComment"># file descriptor or (address stream)</span>
<span id="L292" class="LineNr">292 </span> _test-stream/imm32
<span id="L293" class="LineNr">293 </span> <span class="subxComment"># current write index</span>
<span id="L294" class="LineNr">294 </span> 00 00 00 00
<span id="L295" class="LineNr">295 </span> <span class="subxComment"># current read index</span>
<span id="L296" class="LineNr">296 </span> 00 00 00 00
<span id="L297" class="LineNr">297 </span> <span class="subxComment"># length (6)</span>
<span id="L298" class="LineNr">298 </span> 06 00 00 00
<span id="L299" class="LineNr">299 </span> <span class="subxComment"># data</span>
<span id="L300" class="LineNr">300 </span> 00 00 00 00 00 00 <span class="subxComment"># 6 bytes</span>
<span id="L301" class="LineNr">301 </span>
<span id="L302" class="LineNr">302 </span><span class="subxS2Comment"># . . vim&#0058;nowrap:textwidth=0</span>
</pre>
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53
subx/059read-byte.subx
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@ -34,6 +34,7 @@ Stdin:
# main:
e8/call run-tests/disp32 # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'.
#? e8/call test-read-byte-multiple/disp32
#? e8/call test-read-byte-refills-buffer/disp32
# syscall(exit, Num-test-failures)
8b/copy 0/mod/indirect 5/rm32/.disp32 . . 3/r32/EBX Num-test-failures/disp32 # copy *Num-test-failures to EBX
b8/copy-to-EAX 1/imm32
@ -63,6 +64,8 @@ read-byte: # f : (address buffered-file) -> byte-or-eof/EAX
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . f->read must now be 0; update ECX
31/xor 3/mod/direct 1/rm32/ECX . . . 1/r32/ECX . . # clear ECX
# . EAX = read(f->fd, stream = f+4)
# . . push args
50/push-EAX
@ -231,6 +234,56 @@ test-read-byte-end-of-file:
# . end
c3/return
test-read-byte-refills-buffer:
# - consume buffered-file's buffer, check that next read-byte still works
# setup
# . clear-stream(_test-stream)
# . . push args
68/push _test-stream/imm32
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . clear-stream(_test-buffered-file+4)
# . . push args
b8/copy-to-EAX _test-buffered-file/imm32
05/add-to-EAX 4/imm32
50/push-EAX
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . write(_test-stream, "Abcdefgh")
# . . push args
68/push "Abcdefgh"/imm32
68/push _test-stream/imm32
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# pretend buffer is full
# . _test-buffered-file->read = 6 # >= _test-buffered-file->length
b8/copy-to-EAX _test-buffered-file/imm32
c7/copy 1/mod/*+disp8 0/rm32/EAX . . . . 8/disp8 6/imm32 # copy to *(EAX+8)
# read-byte(_test-buffered-file)
# . . push args
68/push _test-buffered-file/imm32
# . . call
e8/call read-byte/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# check-ints-equal(EAX, 'A', msg)
# . . push args
68/push "F - test-read-byte-refills-buffer"/imm32
68/push 0x41/imm32
50/push-EAX
# . . call
e8/call check-ints-equal/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
# . end
c3/return
== data
# a test buffered file for _test-stream

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subx/apps/crenshaw2-1
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