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<span id="L1" class="LineNr"> 1 </span><span class="SalientComment">//:: simulated x86 registers</span>
<span id="L2" class="LineNr"> 2 </span>
<span id="L3" class="LineNr"> 3 </span><span class="Delimiter">:(before "End Types")</span>
<span id="L4" class="LineNr"> 4 </span><span class="Normal">enum</span> <span class="Delimiter">{</span>
<span id="L5" class="LineNr"> 5 </span> EAX<span class="Delimiter">,</span>
<span id="L6" class="LineNr"> 6 </span> ECX<span class="Delimiter">,</span>
<span id="L7" class="LineNr"> 7 </span> EDX<span class="Delimiter">,</span>
<span id="L8" class="LineNr"> 8 </span> EBX<span class="Delimiter">,</span>
<span id="L9" class="LineNr"> 9 </span> ESP<span class="Delimiter">,</span>
<span id="L10" class="LineNr"> 10 </span> EBP<span class="Delimiter">,</span>
<span id="L11" class="LineNr"> 11 </span> ESI<span class="Delimiter">,</span>
<span id="L12" class="LineNr"> 12 </span> EDI<span class="Delimiter">,</span>
<span id="L13" class="LineNr"> 13 </span> NUM_INT_REGISTERS<span class="Delimiter">,</span>
<span id="L14" class="LineNr"> 14 </span><span class="Delimiter">};</span>
<span id="L15" class="LineNr"> 15 </span><span class="Normal">union</span> reg <span class="Delimiter">{</span>
<span id="L16" class="LineNr"> 16 </span> <span class="Normal">int32_t</span> i<span class="Delimiter">;</span>
<span id="L17" class="LineNr"> 17 </span> <span class="Normal">uint32_t</span> u<span class="Delimiter">;</span>
<span id="L18" class="LineNr"> 18 </span><span class="Delimiter">};</span>
<span id="L19" class="LineNr"> 19 </span><span class="Delimiter">:(before "End Globals")</span>
<span id="L20" class="LineNr"> 20 </span>reg Reg[NUM_INT_REGISTERS] = <span class="Delimiter">{</span> <span class="Delimiter">{</span><span class="Constant">0</span><span class="Delimiter">}</span> <span class="Delimiter">};</span>
<span id="L21" class="LineNr"> 21 </span><span class="Normal">uint32_t</span> EIP = <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L22" class="LineNr"> 22 </span><span class="Delimiter">:(before "End Reset")</span>
<span id="L23" class="LineNr"> 23 </span>bzero<span class="Delimiter">(</span>Reg<span class="Delimiter">,</span> <span class="Normal">sizeof</span><span class="Delimiter">(</span>Reg<span class="Delimiter">));</span>
<span id="L24" class="LineNr"> 24 </span>EIP = <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L25" class="LineNr"> 25 </span>
<span id="L26" class="LineNr"> 26 </span><span class="SalientComment">//:: simulated flag registers; just a subset that we care about</span>
<span id="L27" class="LineNr"> 27 </span>
<span id="L28" class="LineNr"> 28 </span><span class="Delimiter">:(before "End Globals")</span>
<span id="L29" class="LineNr"> 29 </span><span class="Normal">bool</span> SF = <span class="Constant">false</span><span class="Delimiter">;</span> <span class="Comment">// sign flag</span>
<span id="L30" class="LineNr"> 30 </span><span class="Normal">bool</span> ZF = <span class="Constant">false</span><span class="Delimiter">;</span> <span class="Comment">// zero flag</span>
<span id="L31" class="LineNr"> 31 </span><span class="Normal">bool</span> OF = <span class="Constant">false</span><span class="Delimiter">;</span> <span class="Comment">// overflow flag</span>
<span id="L32" class="LineNr"> 32 </span><span class="Delimiter">:(before "End Reset")</span>
<span id="L33" class="LineNr"> 33 </span>SF = ZF = OF = <span class="Constant">false</span><span class="Delimiter">;</span>
<span id="L34" class="LineNr"> 34 </span>
<span id="L35" class="LineNr"> 35 </span><span class="Comment">//: how the flag registers are updated after each instruction</span>
<span id="L36" class="LineNr"> 36 </span>
<span id="L37" class="LineNr"> 37 </span><span class="Delimiter">:(before "End Includes")</span>
<span id="L38" class="LineNr"> 38 </span><span class="Comment">// beware: no side-effects in args</span>
<span id="L39" class="LineNr"> 39 </span><span class="PreProc">#define BINARY_ARITHMETIC_OP(op</span><span class="Delimiter">,</span><span class="PreProc"> arg1</span><span class="Delimiter">,</span><span class="PreProc"> arg2) </span><span class="Delimiter">{</span><span class="PreProc"> \</span>
<span id="L40" class="LineNr"> 40 </span><span class="PreProc"> </span><span class="Comment">/*</span><span class="Comment"> arg1 and arg2 must be signed </span><span class="Comment">*/</span><span class="PreProc"> \</span>
<span id="L41" class="LineNr"> 41 </span><span class="PreProc"> </span><span class="Normal">int64_t</span><span class="PreProc"> tmp = arg1 op arg2</span><span class="Delimiter">;</span><span class="PreProc"> \</span>
<span id="L42" class="LineNr"> 42 </span><span class="PreProc"> arg1 = arg1 op arg2</span><span class="Delimiter">;</span><span class="PreProc"> \</span>
<span id="L43" class="LineNr"> 43 </span><span class="PreProc"> trace(</span><span class="Constant">2</span><span class="Delimiter">,</span><span class="PreProc"> </span><span class="Constant">"run"</span><span class="PreProc">) << </span><span class="Constant">"storing 0x"</span><span class="PreProc"> << HEXWORD << arg1 << end()</span><span class="Delimiter">;</span><span class="PreProc"> \</span>
<span id="L44" class="LineNr"> 44 </span><span class="PreProc"> SF = (arg1 < </span><span class="Constant">0</span><span class="PreProc">)</span><span class="Delimiter">;</span><span class="PreProc"> \</span>
<span id="L45" class="LineNr"> 45 </span><span class="PreProc"> ZF = (arg1 == </span><span class="Constant">0</span><span class="PreProc">)</span><span class="Delimiter">;</span><span class="PreProc"> \</span>
<span id="L46" class="LineNr"> 46 </span><span class="PreProc"> OF = (arg1 != tmp)</span><span class="Delimiter">;</span><span class="PreProc"> \</span>
<span id="L47" class="LineNr"> 47 </span><span class="Delimiter">}</span>
<span id="L48" class="LineNr"> 48 </span>
<span id="L49" class="LineNr"> 49 </span><span class="PreProc">#define BINARY_BITWISE_OP(op</span><span class="Delimiter">,</span><span class="PreProc"> arg1</span><span class="Delimiter">,</span><span class="PreProc"> arg2) </span><span class="Delimiter">{</span><span class="PreProc"> \</span>
<span id="L50" class="LineNr"> 50 </span><span class="PreProc"> </span><span class="Comment">/*</span><span class="Comment"> arg1 and arg2 must be unsigned </span><span class="Comment">*/</span><span class="PreProc"> \</span>
<span id="L51" class="LineNr"> 51 </span><span class="PreProc"> arg1 = arg1 op arg2</span><span class="Delimiter">;</span><span class="PreProc"> \</span>
<span id="L52" class="LineNr"> 52 </span><span class="PreProc"> trace(</span><span class="Constant">2</span><span class="Delimiter">,</span><span class="PreProc"> </span><span class="Constant">"run"</span><span class="PreProc">) << </span><span class="Constant">"storing 0x"</span><span class="PreProc"> << HEXWORD << arg1 << end()</span><span class="Delimiter">;</span><span class="PreProc"> \</span>
<span id="L53" class="LineNr"> 53 </span><span class="PreProc"> SF = (arg1 >> </span><span class="Constant">31</span><span class="PreProc">)</span><span class="Delimiter">;</span><span class="PreProc"> \</span>
<span id="L54" class="LineNr"> 54 </span><span class="PreProc"> ZF = (arg1 == </span><span class="Constant">0</span><span class="PreProc">)</span><span class="Delimiter">;</span><span class="PreProc"> \</span>
<span id="L55" class="LineNr"> 55 </span><span class="PreProc"> OF = </span><span class="Constant">false</span><span class="Delimiter">;</span><span class="PreProc"> \</span>
<span id="L56" class="LineNr"> 56 </span><span class="Delimiter">}</span>
<span id="L57" class="LineNr"> 57 </span>
<span id="L58" class="LineNr"> 58 </span><span class="SalientComment">//:: simulated RAM</span>
<span id="L59" class="LineNr"> 59 </span>
<span id="L60" class="LineNr"> 60 </span><span class="Delimiter">:(before "End Globals")</span>
<span id="L61" class="LineNr"> 61 </span>vector<<span class="Normal">uint8_t</span>> Mem<span class="Delimiter">;</span>
<span id="L62" class="LineNr"> 62 </span><span class="Normal">uint32_t</span> End_of_program = <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L63" class="LineNr"> 63 </span><span class="Delimiter">:(before "End Reset")</span>
<span id="L64" class="LineNr"> 64 </span>Mem<span class="Delimiter">.</span>clear<span class="Delimiter">();</span>
<span id="L65" class="LineNr"> 65 </span>Mem<span class="Delimiter">.</span>resize<span class="Delimiter">(</span><span class="Constant">1024</span><span class="Delimiter">);</span>
<span id="L66" class="LineNr"> 66 </span>End_of_program = <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L67" class="LineNr"> 67 </span>
<span id="L68" class="LineNr"> 68 </span><span class="SalientComment">//:: core interpreter loop</span>
<span id="L69" class="LineNr"> 69 </span>
<span id="L70" class="LineNr"> 70 </span><span class="Delimiter">:(scenario add_imm32_to_eax)</span>
<span id="L71" class="LineNr"> 71 </span><span class="Comment"># In scenarios, programs are a series of hex bytes, each (variable-length)</span>
<span id="L72" class="LineNr"> 72 </span><span class="Comment"># instruction on one line.</span>
<span id="L73" class="LineNr"> 73 </span>#
<span id="L74" class="LineNr"> 74 </span><span class="Comment"># x86 instructions consist of the following parts (see cheatsheet.pdf):</span>
<span id="L75" class="LineNr"> 75 </span><span class="Comment"># opcode ModR/M SIB displacement immediate</span>
<span id="L76" class="LineNr"> 76 </span><span class="Comment"># instruction mod, reg, Reg/Mem bits scale, index, base</span>
<span id="L77" class="LineNr"> 77 </span><span class="Comment"># 1-3 bytes 0/1 byte 0/1 byte 0/1/2/4 bytes 0/1/2/4 bytes</span>
<span id="L78" class="LineNr"> 78 </span> <span class="Conceal">¦</span> <span class="PreProc">0</span><span class="Constant">5</span> 0a 0b 0c 0d <span class="Comment"># add 0x0d0c0b0a to EAX</span>
<span id="L79" class="LineNr"> 79 </span><span class="Comment"># All hex bytes must be exactly 2 characters each. No '0x' prefixes.</span>
<span id="L80" class="LineNr"> 80 </span><span class="traceContains">+load: 1 -> 05</span>
<span id="L81" class="LineNr"> 81 </span><span class="traceContains">+load: 2 -> 0a</span>
<span id="L82" class="LineNr"> 82 </span><span class="traceContains">+load: 3 -> 0b</span>
<span id="L83" class="LineNr"> 83 </span><span class="traceContains">+load: 4 -> 0c</span>
<span id="L84" class="LineNr"> 84 </span><span class="traceContains">+load: 5 -> 0d</span>
<span id="L85" class="LineNr"> 85 </span><span class="traceContains">+run: add imm32 0x0d0c0b0a to reg EAX</span>
<span id="L86" class="LineNr"> 86 </span><span class="traceContains">+run: storing 0x0d0c0b0a</span>
<span id="L87" class="LineNr"> 87 </span>
<span id="L88" class="LineNr"> 88 </span><span class="Delimiter">:(code)</span>
<span id="L89" class="LineNr"> 89 </span><span class="Comment">// helper for tests: load a program into memory from a textual representation</span>
<span id="L90" class="LineNr"> 90 </span><span class="Comment">// of its bytes, and run it</span>
<span id="L91" class="LineNr"> 91 </span><span class="Normal">void</span> run<span class="Delimiter">(</span><span class="Normal">const</span> string& text_bytes<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L92" class="LineNr"> 92 </span> load_program<span class="Delimiter">(</span>text_bytes<span class="Delimiter">);</span>
<span id="L93" class="LineNr"> 93 </span> EIP = <span class="Constant">1</span><span class="Delimiter">;</span> <span class="Comment">// preserve null pointer</span>
<span id="L94" class="LineNr"> 94 </span> <span class="Normal">while</span> <span class="Delimiter">(</span>EIP < End_of_program<span class="Delimiter">)</span>
<span id="L95" class="LineNr"> 95 </span> <span class="Conceal">¦</span> run_one_instruction<span class="Delimiter">();</span>
<span id="L96" class="LineNr"> 96 </span><span class="Delimiter">}</span>
<span id="L97" class="LineNr"> 97 </span>
<span id="L98" class="LineNr"> 98 </span><span class="Comment">// skeleton of how x86 instructions are decoded</span>
<span id="L99" class="LineNr"> 99 </span><span class="Normal">void</span> run_one_instruction<span class="Delimiter">()</span> <span class="Delimiter">{</span>
<span id="L100" class="LineNr">100 </span> <span class="Normal">uint8_t</span> op=<span class="Constant">0</span><span class="Delimiter">,</span> op2=<span class="Constant">0</span><span class="Delimiter">,</span> op3=<span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L101" class="LineNr">101 </span> <span class="Normal">switch</span> <span class="Delimiter">(</span>op = next<span class="Delimiter">())</span> <span class="Delimiter">{</span>
<span id="L102" class="LineNr">102 </span> <span class="Normal">case</span> <span class="Constant">0xf4</span>: <span class="Comment">// hlt</span>
<span id="L103" class="LineNr">103 </span> <span class="Conceal">¦</span> EIP = End_of_program<span class="Delimiter">;</span>
<span id="L104" class="LineNr">104 </span> <span class="Conceal">¦</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L105" class="LineNr">105 </span> <span class="Comment">// our first opcode</span>
<span id="L106" class="LineNr">106 </span> <span class="Normal">case</span> <span class="Constant">0x05</span>: <span class="Delimiter">{</span> <span class="Comment">// add imm32 to EAX</span>
<span id="L107" class="LineNr">107 </span> <span class="Conceal">¦</span> <span class="Normal">int32_t</span> arg2 = imm32<span class="Delimiter">();</span>
<span id="L108" class="LineNr">108 </span> <span class="Conceal">¦</span> trace<span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">)</span> << <span class="Constant">"add imm32 0x"</span> << HEXWORD << arg2 << <span class="Constant">" to reg EAX"</span> << end<span class="Delimiter">();</span>
<span id="L109" class="LineNr">109 </span> <span class="Conceal">¦</span> BINARY_ARITHMETIC_OP<span class="Delimiter">(</span>+<span class="Delimiter">,</span> Reg[EAX]<span class="Delimiter">.</span>i<span class="Delimiter">,</span> arg2<span class="Delimiter">);</span>
<span id="L110" class="LineNr">110 </span> <span class="Conceal">¦</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L111" class="LineNr">111 </span> <span class="Delimiter">}</span>
<span id="L112" class="LineNr">112 </span> <span class="Comment">// End Single-Byte Opcodes</span>
<span id="L113" class="LineNr">113 </span> <span class="Normal">case</span> <span class="Constant">0x0f</span>:
<span id="L114" class="LineNr">114 </span> <span class="Conceal">¦</span> <span class="Normal">switch</span><span class="Delimiter">(</span>op2 = next<span class="Delimiter">())</span> <span class="Delimiter">{</span>
<span id="L115" class="LineNr">115 </span> <span class="Conceal">¦</span> <span class="Comment">// End Two-Byte Opcodes Starting With 0f</span>
<span id="L116" class="LineNr">116 </span> <span class="Conceal">¦</span> <span class="Normal">default</span>:
<span id="L117" class="LineNr">117 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> cerr << <span class="Constant">"unrecognized second opcode after 0f: "</span> << HEXBYTE << NUM<span class="Delimiter">(</span>op2<span class="Delimiter">)</span> << <span class="cSpecial">'\n'</span><span class="Delimiter">;</span>
<span id="L118" class="LineNr">118 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L119" class="LineNr">119 </span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L120" class="LineNr">120 </span> <span class="Conceal">¦</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L121" class="LineNr">121 </span> <span class="Normal">case</span> <span class="Constant">0xf3</span>:
<span id="L122" class="LineNr">122 </span> <span class="Conceal">¦</span> <span class="Normal">switch</span><span class="Delimiter">(</span>op2 = next<span class="Delimiter">())</span> <span class="Delimiter">{</span>
<span id="L123" class="LineNr">123 </span> <span class="Conceal">¦</span> <span class="Comment">// End Two-Byte Opcodes Starting With f3</span>
<span id="L124" class="LineNr">124 </span> <span class="Conceal">¦</span> <span class="Normal">case</span> <span class="Constant">0x0f</span>:
<span id="L125" class="LineNr">125 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Normal">switch</span><span class="Delimiter">(</span>op3 = next<span class="Delimiter">())</span> <span class="Delimiter">{</span>
<span id="L126" class="LineNr">126 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment">// End Three-Byte Opcodes Starting With f3 0f</span>
<span id="L127" class="LineNr">127 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Normal">default</span>:
<span id="L128" class="LineNr">128 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> cerr << <span class="Constant">"unrecognized third opcode after f3 0f: "</span> << HEXBYTE << NUM<span class="Delimiter">(</span>op3<span class="Delimiter">)</span> << <span class="cSpecial">'\n'</span><span class="Delimiter">;</span>
<span id="L129" class="LineNr">129 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L130" class="LineNr">130 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L131" class="LineNr">131 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L132" class="LineNr">132 </span> <span class="Conceal">¦</span> <span class="Normal">default</span>:
<span id="L133" class="LineNr">133 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> cerr << <span class="Constant">"unrecognized second opcode after f3: "</span> << HEXBYTE << NUM<span class="Delimiter">(</span>op2<span class="Delimiter">)</span> << <span class="cSpecial">'\n'</span><span class="Delimiter">;</span>
<span id="L134" class="LineNr">134 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L135" class="LineNr">135 </span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L136" class="LineNr">136 </span> <span class="Conceal">¦</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L137" class="LineNr">137 </span> <span class="Normal">default</span>:
<span id="L138" class="LineNr">138 </span> <span class="Conceal">¦</span> cerr << <span class="Constant">"unrecognized opcode: "</span> << HEXBYTE << NUM<span class="Delimiter">(</span>op<span class="Delimiter">)</span> << <span class="cSpecial">'\n'</span><span class="Delimiter">;</span>
<span id="L139" class="LineNr">139 </span> <span class="Conceal">¦</span> exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L140" class="LineNr">140 </span> <span class="Delimiter">}</span>
<span id="L141" class="LineNr">141 </span><span class="Delimiter">}</span>
<span id="L142" class="LineNr">142 </span>
<span id="L143" class="LineNr">143 </span><span class="Normal">void</span> load_program<span class="Delimiter">(</span><span class="Normal">const</span> string& text_bytes<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L144" class="LineNr">144 </span> <span class="Normal">uint32_t</span> addr = <span class="Constant">1</span><span class="Delimiter">;</span>
<span id="L145" class="LineNr">145 </span> istringstream in<span class="Delimiter">(</span>text_bytes<span class="Delimiter">);</span>
<span id="L146" class="LineNr">146 </span> in >> std::noskipws<span class="Delimiter">;</span>
<span id="L147" class="LineNr">147 </span> <span class="Normal">while</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L148" class="LineNr">148 </span> <span class="Conceal">¦</span> <span class="Normal">char</span> c1 = next_hex_byte<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
<span id="L149" class="LineNr">149 </span> <span class="Conceal">¦</span> <span class="Normal">if</span> <span class="Delimiter">(</span>c1 == <span class="cSpecial">'\0'</span><span class="Delimiter">)</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L150" class="LineNr">150 </span> <span class="Conceal">¦</span> <span class="Normal">if</span> <span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L151" class="LineNr">151 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> raise << <span class="Constant">"input program truncated mid-byte</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span>
<span id="L152" class="LineNr">152 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Identifier">return</span><span class="Delimiter">;</span>
<span id="L153" class="LineNr">153 </span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L154" class="LineNr">154 </span> <span class="Conceal">¦</span> <span class="Normal">char</span> c2 = next_hex_byte<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
<span id="L155" class="LineNr">155 </span> <span class="Conceal">¦</span> <span class="Normal">if</span> <span class="Delimiter">(</span>c2 == <span class="cSpecial">'\0'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L156" class="LineNr">156 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> raise << <span class="Constant">"input program truncated mid-byte</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span>
<span id="L157" class="LineNr">157 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Identifier">return</span><span class="Delimiter">;</span>
<span id="L158" class="LineNr">158 </span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L159" class="LineNr">159 </span> <span class="Conceal">¦</span> Mem<span class="Delimiter">.</span>at<span class="Delimiter">(</span>addr<span class="Delimiter">)</span> = to_byte<span class="Delimiter">(</span>c1<span class="Delimiter">,</span> c2<span class="Delimiter">);</span>
<span id="L160" class="LineNr">160 </span> <span class="Conceal">¦</span> trace<span class="Delimiter">(</span><span class="Constant">99</span><span class="Delimiter">,</span> <span class="Constant">"load"</span><span class="Delimiter">)</span> << addr << <span class="Constant">" -> "</span> << HEXBYTE << NUM<span class="Delimiter">(</span>Mem<span class="Delimiter">.</span>at<span class="Delimiter">(</span>addr<span class="Delimiter">))</span> << end<span class="Delimiter">();</span>
<span id="L161" class="LineNr">161 </span> <span class="Conceal">¦</span> addr++<span class="Delimiter">;</span>
<span id="L162" class="LineNr">162 </span> <span class="Delimiter">}</span>
<span id="L163" class="LineNr">163 </span> End_of_program = addr<span class="Delimiter">;</span>
<span id="L164" class="LineNr">164 </span><span class="Delimiter">}</span>
<span id="L165" class="LineNr">165 </span>
<span id="L166" class="LineNr">166 </span><span class="Normal">char</span> next_hex_byte<span class="Delimiter">(</span>istream& in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L167" class="LineNr">167 </span> <span class="Normal">while</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L168" class="LineNr">168 </span> <span class="Conceal">¦</span> <span class="Normal">char</span> c = <span class="cSpecial">'\0'</span><span class="Delimiter">;</span>
<span id="L169" class="LineNr">169 </span> <span class="Conceal">¦</span> in >> c<span class="Delimiter">;</span>
<span id="L170" class="LineNr">170 </span> <span class="Conceal">¦</span> <span class="Normal">if</span> <span class="Delimiter">(</span>c == <span class="Constant">' '</span> || c == <span class="cSpecial">'\n'</span><span class="Delimiter">)</span> <span class="Identifier">continue</span><span class="Delimiter">;</span>
<span id="L171" class="LineNr">171 </span> <span class="Conceal">¦</span> <span class="Normal">while</span> <span class="Delimiter">(</span>c == <span class="Constant">'#'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L172" class="LineNr">172 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Normal">while</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L173" class="LineNr">173 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> in >> c<span class="Delimiter">;</span>
<span id="L174" class="LineNr">174 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Normal">if</span> <span class="Delimiter">(</span>c == <span class="cSpecial">'\n'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L175" class="LineNr">175 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> in >> c<span class="Delimiter">;</span>
<span id="L176" class="LineNr">176 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L177" class="LineNr">177 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L178" class="LineNr">178 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L179" class="LineNr">179 </span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L180" class="LineNr">180 </span> <span class="Conceal">¦</span> <span class="Normal">if</span> <span class="Delimiter">(</span>c >= <span class="Constant">'0'</span> && c <= <span class="Constant">'9'</span><span class="Delimiter">)</span> <span class="Identifier">return</span> c<span class="Delimiter">;</span>
<span id="L181" class="LineNr">181 </span> <span class="Conceal">¦</span> <span class="Normal">else</span> <span class="Normal">if</span> <span class="Delimiter">(</span>c >= <span class="Constant">'a'</span> && c <= <span class="Constant">'f'</span><span class="Delimiter">)</span> <span class="Identifier">return</span> c<span class="Delimiter">;</span>
<span id="L182" class="LineNr">182 </span> <span class="Conceal">¦</span> <span class="Normal">else</span> <span class="Normal">if</span> <span class="Delimiter">(</span>c >= <span class="Constant">'A'</span> && c <= <span class="Constant">'F'</span><span class="Delimiter">)</span> <span class="Identifier">return</span> tolower<span class="Delimiter">(</span>c<span class="Delimiter">);</span>
<span id="L183" class="LineNr">183 </span> <span class="Conceal">¦</span> <span class="Comment">// disallow any non-hex characters, including a '0x' prefix</span>
<span id="L184" class="LineNr">184 </span> <span class="Conceal">¦</span> <span class="Normal">if</span> <span class="Delimiter">(</span>!isspace<span class="Delimiter">(</span>c<span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L185" class="LineNr">185 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> raise << <span class="Constant">"invalid non-hex character '"</span> << c << <span class="Constant">"'</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span>
<span id="L186" class="LineNr">186 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L187" class="LineNr">187 </span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L188" class="LineNr">188 </span> <span class="Delimiter">}</span>
<span id="L189" class="LineNr">189 </span> <span class="Identifier">return</span> <span class="cSpecial">'\0'</span><span class="Delimiter">;</span>
<span id="L190" class="LineNr">190 </span><span class="Delimiter">}</span>
<span id="L191" class="LineNr">191 </span>
<span id="L192" class="LineNr">192 </span><span class="Normal">uint8_t</span> to_byte<span class="Delimiter">(</span><span class="Normal">char</span> hex_byte1<span class="Delimiter">,</span> <span class="Normal">char</span> hex_byte2<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L193" class="LineNr">193 </span> <span class="Identifier">return</span> to_hex_num<span class="Delimiter">(</span>hex_byte1<span class="Delimiter">)</span>*<span class="Constant">16</span> + to_hex_num<span class="Delimiter">(</span>hex_byte2<span class="Delimiter">);</span>
<span id="L194" class="LineNr">194 </span><span class="Delimiter">}</span>
<span id="L195" class="LineNr">195 </span><span class="Normal">uint8_t</span> to_hex_num<span class="Delimiter">(</span><span class="Normal">char</span> c<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L196" class="LineNr">196 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>c >= <span class="Constant">'0'</span> && c <= <span class="Constant">'9'</span><span class="Delimiter">)</span> <span class="Identifier">return</span> c - <span class="Constant">'0'</span><span class="Delimiter">;</span>
<span id="L197" class="LineNr">197 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>c >= <span class="Constant">'a'</span> && c <= <span class="Constant">'f'</span><span class="Delimiter">)</span> <span class="Identifier">return</span> c - <span class="Constant">'a'</span> + <span class="Constant">10</span><span class="Delimiter">;</span>
<span id="L198" class="LineNr">198 </span> assert<span class="Delimiter">(</span><span class="Constant">false</span><span class="Delimiter">);</span>
<span id="L199" class="LineNr">199 </span> <span class="Identifier">return</span> <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L200" class="LineNr">200 </span><span class="Delimiter">}</span>
<span id="L201" class="LineNr">201 </span>
<span id="L202" class="LineNr">202 </span><span class="Normal">inline</span> <span class="Normal">uint8_t</span> next<span class="Delimiter">()</span> <span class="Delimiter">{</span>
<span id="L203" class="LineNr">203 </span> <span class="Identifier">return</span> Mem<span class="Delimiter">.</span>at<span class="Delimiter">(</span>EIP++<span class="Delimiter">);</span>
<span id="L204" class="LineNr">204 </span><span class="Delimiter">}</span>
<span id="L205" class="LineNr">205 </span>
<span id="L206" class="LineNr">206 </span><span class="Comment">// read a 32-bit immediate in little-endian order from the instruction stream</span>
<span id="L207" class="LineNr">207 </span><span class="Normal">int32_t</span> imm32<span class="Delimiter">()</span> <span class="Delimiter">{</span>
<span id="L208" class="LineNr">208 </span> <span class="Normal">int32_t</span> result = next<span class="Delimiter">();</span>
<span id="L209" class="LineNr">209 </span> result |= <span class="Delimiter">(</span>next<span class="Delimiter">()</span><<<span class="Constant">8</span><span class="Delimiter">);</span>
<span id="L210" class="LineNr">210 </span> result |= <span class="Delimiter">(</span>next<span class="Delimiter">()</span><<<span class="Constant">16</span><span class="Delimiter">);</span>
<span id="L211" class="LineNr">211 </span> result |= <span class="Delimiter">(</span>next<span class="Delimiter">()</span><<<span class="Constant">24</span><span class="Delimiter">);</span>
<span id="L212" class="LineNr">212 </span> <span class="Identifier">return</span> result<span class="Delimiter">;</span>
<span id="L213" class="LineNr">213 </span><span class="Delimiter">}</span>
<span id="L214" class="LineNr">214 </span>
<span id="L215" class="LineNr">215 </span><span class="Delimiter">:(before "End Includes")</span>
<span id="L216" class="LineNr">216 </span><span class="PreProc">#include </span><span class="Constant"><iomanip></span>
<span id="L217" class="LineNr">217 </span><span class="PreProc">#define HEXBYTE std::hex << std::setw(</span><span class="Constant">2</span><span class="PreProc">) << std::setfill(</span><span class="Constant">'0'</span><span class="PreProc">)</span>
<span id="L218" class="LineNr">218 </span><span class="PreProc">#define HEXWORD std::hex << std::setw(</span><span class="Constant">8</span><span class="PreProc">) << std::setfill(</span><span class="Constant">'0'</span><span class="PreProc">)</span>
<span id="L219" class="LineNr">219 </span><span class="Comment">// ugly that iostream doesn't print uint8_t as an integer</span>
<span id="L220" class="LineNr">220 </span><span class="PreProc">#define NUM(X) </span><span class="Normal">static_cast</span><span class="PreProc"><</span><span class="Normal">int</span><span class="PreProc">>(X)</span>
<span id="L221" class="LineNr">221 </span><span class="PreProc">#include </span><span class="Constant"><stdint.h></span>
</pre>
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