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4085 - done with first cut of the SubX VM 

subx: 'call' and 'return' instructions
This commit is contained in:
Kartik K. Agaram 2017-10-18 03:11:56 -07:00
parent 8a0268317f
commit 292ccba1bb
4 changed files with 226 additions and 6 deletions
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6
html/subx/012indirect_addressing.cc.html
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@ -388,11 +388,11 @@ if ('onhashchange' in window) {
<span id="L323" class="LineNr">323 </span><span class="traceAbsent">-run: inst: 0x00000003</span>
<span id="L324" class="LineNr">324 </span>
<span id="L325" class="LineNr">325 </span><span class="Delimiter">:(before &quot;End Single-Byte Opcodes&quot;)</span>
<span id="L326" class="LineNr">326 </span><span class="Normal">case</span> <span class="Constant">0xff</span>: <span class="Delimiter">{</span> <span class="Comment">// jump to r/m32</span>
<span id="L326" class="LineNr">326 </span><span class="Normal">case</span> <span class="Constant">0xff</span>: <span class="Delimiter">{</span>
<span id="L327" class="LineNr">327 </span> <span class="Normal">uint8_t</span> modrm = <a href='010core.cc.html#L214'>next</a><span class="Delimiter">();</span>
<span id="L328" class="LineNr">328 </span> <span class="Normal">uint8_t</span> subop = <span class="Delimiter">(</span>modrm&gt;&gt;<span class="Constant">3</span><span class="Delimiter">)</span>&amp;<span class="Constant">0x7</span><span class="Delimiter">;</span> <span class="Comment">// middle 3 'reg opcode' bits</span>
<span id="L329" class="LineNr">329 </span> <span class="Normal">switch</span> <span class="Delimiter">(</span>subop<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L330" class="LineNr">330 </span> <span class="Conceal">¦</span> <span class="Normal">case</span> <span class="Constant">4</span>: <span class="Delimiter">{</span>
<span id="L330" class="LineNr">330 </span> <span class="Conceal">¦</span> <span class="Normal">case</span> <span class="Constant">4</span>: <span class="Delimiter">{</span> <span class="Comment">// jump to r/m32</span>
<span id="L331" class="LineNr">331 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='003trace.cc.html#L160'>trace</a><span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;jump to effective address&quot;</span> &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
<span id="L332" class="LineNr">332 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Normal">int32_t</span>* arg2 = <a href='011direct_addressing.cc.html#L26'>effective_address</a><span class="Delimiter">(</span>modrm<span class="Delimiter">);</span>
<span id="L333" class="LineNr">333 </span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='010core.cc.html#L23'>EIP</a> = *arg2<span class="Delimiter">;</span>
@ -418,7 +418,7 @@ if ('onhashchange' in window) {
<span id="L353" class="LineNr">353 </span><span class="traceContains">+run: pushing value 0x000000af</span>
<span id="L354" class="LineNr">354 </span>
<span id="L355" class="LineNr">355 </span><span class="Delimiter">:(before &quot;End Op ff Subops&quot;)</span>
<span id="L356" class="LineNr">356 </span><span class="Normal">case</span> <span class="Constant">6</span>: <span class="Delimiter">{</span>
<span id="L356" class="LineNr">356 </span><span class="Normal">case</span> <span class="Constant">6</span>: <span class="Delimiter">{</span> <span class="Comment">// push r/m32 to stack</span>
<span id="L357" class="LineNr">357 </span> <a href='003trace.cc.html#L160'>trace</a><span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;push effective address&quot;</span> &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
<span id="L358" class="LineNr">358 </span> <span class="Normal">const</span> <span class="Normal">int32_t</span>* val = <a href='011direct_addressing.cc.html#L26'>effective_address</a><span class="Delimiter">(</span>modrm<span class="Delimiter">);</span>
<span id="L359" class="LineNr">359 </span> <a href='011direct_addressing.cc.html#L244'>push</a><span class="Delimiter">(</span>*val<span class="Delimiter">);</span>

143
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<pre id='vimCodeElement'>
<span id="L1" class="LineNr"> 1 </span><span class="SalientComment">//:: call</span>
<span id="L2" class="LineNr"> 2 </span>
<span id="L3" class="LineNr"> 3 </span><span class="Delimiter">:(scenario call_imm32)</span>
<span id="L4" class="LineNr"> 4 </span><span class="Special">% Reg[ESP].u = 0x64;</span>
<span id="L5" class="LineNr"> 5 </span><span class="Comment"># op ModRM SIB displacement immediate</span>
<span id="L6" class="LineNr"> 6 </span> e8 a0 <span class="PreProc">0</span><span class="Constant">0</span> <span class="PreProc">0</span><span class="Constant">0</span> <span class="PreProc">0</span><span class="Constant">0</span> <span class="Comment"># call function offset at 0x000000a0</span>
<span id="L7" class="LineNr"> 7 </span> <span class="Comment"># next EIP is 6</span>
<span id="L8" class="LineNr"> 8 </span><span class="traceContains">+run: call <a href='010core.cc.html#L219'>imm32</a> 0x000000a0</span>
<span id="L9" class="LineNr"> 9 </span><span class="traceContains">+run: decrementing <a href='010core.cc.html#L11'>ESP</a> to 0x00000060</span>
<span id="L10" class="LineNr">10 </span><span class="traceContains">+run: pushing value 0x00000006</span>
<span id="L11" class="LineNr">11 </span><span class="traceContains">+run: jumping to 0x000000a6</span>
<span id="L12" class="LineNr">12 </span>
<span id="L13" class="LineNr">13 </span><span class="Delimiter">:(before &quot;End Single-Byte Opcodes&quot;)</span>
<span id="L14" class="LineNr">14 </span><span class="Normal">case</span> <span class="Constant">0xe8</span>: <span class="Delimiter">{</span> <span class="Comment">// call imm32 relative to next EIP</span>
<span id="L15" class="LineNr">15 </span> <span class="Normal">int32_t</span> offset = <a href='010core.cc.html#L219'>imm32</a><span class="Delimiter">();</span>
<span id="L16" class="LineNr">16 </span> <a href='003trace.cc.html#L160'>trace</a><span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;call <a href='010core.cc.html#L219'>imm32</a> 0x&quot;</span> &lt;&lt; <a href='010core.cc.html#L230'>HEXWORD</a> &lt;&lt; offset &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
<span id="L17" class="LineNr">17 </span> <a href='011direct_addressing.cc.html#L244'>push</a><span class="Delimiter">(</span><a href='010core.cc.html#L23'>EIP</a><span class="Delimiter">);</span>
<span id="L18" class="LineNr">18 </span> <a href='010core.cc.html#L23'>EIP</a> += offset<span class="Delimiter">;</span>
<span id="L19" class="LineNr">19 </span> <a href='003trace.cc.html#L160'>trace</a><span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;jumping to 0x&quot;</span> &lt;&lt; <a href='010core.cc.html#L230'>HEXWORD</a> &lt;&lt; <a href='010core.cc.html#L23'>EIP</a> &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
<span id="L20" class="LineNr">20 </span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L21" class="LineNr">21 </span><span class="Delimiter">}</span>
<span id="L22" class="LineNr">22 </span>
<span id="L23" class="LineNr">23 </span><span class="Comment">//:</span>
<span id="L24" class="LineNr">24 </span>
<span id="L25" class="LineNr">25 </span><span class="Delimiter">:(scenario call_r32)</span>
<span id="L26" class="LineNr">26 </span><span class="Special">% Reg[ESP].u = 0x64;</span>
<span id="L27" class="LineNr">27 </span><span class="Special">% Reg[EBX].u = 0x000000a0;</span>
<span id="L28" class="LineNr">28 </span><span class="Comment"># op ModRM SIB displacement immediate</span>
<span id="L29" class="LineNr">29 </span> ff d3 <span class="Comment"># call function offset at EBX (reg 3)</span>
<span id="L30" class="LineNr">30 </span> <span class="Comment"># next EIP is 3</span>
<span id="L31" class="LineNr">31 </span><span class="traceContains">+run: call to effective address</span>
<span id="L32" class="LineNr">32 </span><span class="traceContains">+run: effective address is <a href='010core.cc.html#L17'>reg</a> 3</span>
<span id="L33" class="LineNr">33 </span><span class="traceContains">+run: decrementing <a href='010core.cc.html#L11'>ESP</a> to 0x00000060</span>
<span id="L34" class="LineNr">34 </span><span class="traceContains">+run: pushing value 0x00000003</span>
<span id="L35" class="LineNr">35 </span><span class="traceContains">+run: jumping to 0x000000a3</span>
<span id="L36" class="LineNr">36 </span>
<span id="L37" class="LineNr">37 </span><span class="Delimiter">:(before &quot;End Op ff Subops&quot;)</span>
<span id="L38" class="LineNr">38 </span><span class="Normal">case</span> <span class="Constant">2</span>: <span class="Delimiter">{</span> <span class="Comment">// call function pointer at r/m32</span>
<span id="L39" class="LineNr">39 </span> <a href='003trace.cc.html#L160'>trace</a><span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;call to effective address&quot;</span> &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
<span id="L40" class="LineNr">40 </span> <span class="Normal">int32_t</span>* offset = <a href='011direct_addressing.cc.html#L26'>effective_address</a><span class="Delimiter">(</span>modrm<span class="Delimiter">);</span>
<span id="L41" class="LineNr">41 </span> <a href='011direct_addressing.cc.html#L244'>push</a><span class="Delimiter">(</span><a href='010core.cc.html#L23'>EIP</a><span class="Delimiter">);</span>
<span id="L42" class="LineNr">42 </span> <a href='010core.cc.html#L23'>EIP</a> += *offset<span class="Delimiter">;</span>
<span id="L43" class="LineNr">43 </span> <a href='003trace.cc.html#L160'>trace</a><span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;jumping to 0x&quot;</span> &lt;&lt; <a href='010core.cc.html#L230'>HEXWORD</a> &lt;&lt; <a href='010core.cc.html#L23'>EIP</a> &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
<span id="L44" class="LineNr">44 </span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L45" class="LineNr">45 </span><span class="Delimiter">}</span>
<span id="L46" class="LineNr">46 </span>
<span id="L47" class="LineNr">47 </span><span class="Delimiter">:(scenario call_mem_at_r32)</span>
<span id="L48" class="LineNr">48 </span><span class="Special">% Reg[ESP].u = 0x64;</span>
<span id="L49" class="LineNr">49 </span><span class="Special">% Reg[EBX].u = 0x10;</span>
<span id="L50" class="LineNr">50 </span><span class="Special">% SET_WORD_IN_MEM(0x10, 0x000000a0);</span>
<span id="L51" class="LineNr">51 </span><span class="Comment"># op ModRM SIB displacement immediate</span>
<span id="L52" class="LineNr">52 </span> ff <span class="Constant">13</span> <span class="Comment"># call function offset at *EBX (reg 3)</span>
<span id="L53" class="LineNr">53 </span> <span class="Comment"># next EIP is 3</span>
<span id="L54" class="LineNr">54 </span><span class="traceContains">+run: call to effective address</span>
<span id="L55" class="LineNr">55 </span><span class="traceContains">+run: effective address is mem at address 0x10 (reg 3)</span>
<span id="L56" class="LineNr">56 </span><span class="traceContains">+run: decrementing <a href='010core.cc.html#L11'>ESP</a> to 0x00000060</span>
<span id="L57" class="LineNr">57 </span><span class="traceContains">+run: pushing value 0x00000003</span>
<span id="L58" class="LineNr">58 </span><span class="traceContains">+run: jumping to 0x000000a3</span>
<span id="L59" class="LineNr">59 </span>
<span id="L60" class="LineNr">60 </span><span class="SalientComment">//:: ret</span>
<span id="L61" class="LineNr">61 </span>
<span id="L62" class="LineNr">62 </span><span class="Delimiter">:(scenario ret)</span>
<span id="L63" class="LineNr">63 </span><span class="Special">% Reg[ESP].u = 0x60;</span>
<span id="L64" class="LineNr">64 </span><span class="Special">% SET_WORD_IN_MEM(0x60, 0x00000010);</span>
<span id="L65" class="LineNr">65 </span><span class="Comment"># op ModRM SIB displacement immediate</span>
<span id="L66" class="LineNr">66 </span> c3
<span id="L67" class="LineNr">67 </span><span class="traceContains">+run: return</span>
<span id="L68" class="LineNr">68 </span><span class="traceContains">+run: popping value 0x00000010</span>
<span id="L69" class="LineNr">69 </span><span class="traceContains">+run: jumping to 0x00000010</span>
<span id="L70" class="LineNr">70 </span>
<span id="L71" class="LineNr">71 </span><span class="Delimiter">:(before &quot;End Single-Byte Opcodes&quot;)</span>
<span id="L72" class="LineNr">72 </span><span class="Normal">case</span> <span class="Constant">0xc3</span>: <span class="Delimiter">{</span> <span class="Comment">// return from a call</span>
<span id="L73" class="LineNr">73 </span> <a href='003trace.cc.html#L160'>trace</a><span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;return&quot;</span> &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
<span id="L74" class="LineNr">74 </span> <a href='010core.cc.html#L23'>EIP</a> = <a href='011direct_addressing.cc.html#L277'>pop</a><span class="Delimiter">();</span>
<span id="L75" class="LineNr">75 </span> <a href='003trace.cc.html#L160'>trace</a><span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;jumping to 0x&quot;</span> &lt;&lt; <a href='010core.cc.html#L230'>HEXWORD</a> &lt;&lt; <a href='010core.cc.html#L23'>EIP</a> &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
<span id="L76" class="LineNr">76 </span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L77" class="LineNr">77 </span><span class="Delimiter">}</span>
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6
subx/012indirect_addressing.cc
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@ -323,11 +323,11 @@ case 0x8b: { // copy r32 to r/m32
-run: inst: 0x00000003
:(before "End Single-Byte Opcodes")
case 0xff: { // jump to r/m32
case 0xff: {
uint8_t modrm = next();
uint8_t subop = (modrm>>3)&0x7; // middle 3 'reg opcode' bits
switch (subop) {
case 4: {
case 4: { // jump to r/m32
trace(2, "run") << "jump to effective address" << end();
int32_t* arg2 = effective_address(modrm);
EIP = *arg2;
@ -353,7 +353,7 @@ case 0xff: { // jump to r/m32
+run: pushing value 0x000000af
:(before "End Op ff Subops")
case 6: {
case 6: { // push r/m32 to stack
trace(2, "run") << "push effective address" << end();
const int32_t* val = effective_address(modrm);
push(*val);

77
subx/016functions.cc Normal file
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@ -0,0 +1,77 @@
//:: call
:(scenario call_imm32)
% Reg[ESP].u = 0x64;
# op ModRM SIB displacement immediate
e8 a0 00 00 00 # call function offset at 0x000000a0
# next EIP is 6
+run: call imm32 0x000000a0
+run: decrementing ESP to 0x00000060
+run: pushing value 0x00000006
+run: jumping to 0x000000a6
:(before "End Single-Byte Opcodes")
case 0xe8: { // call imm32 relative to next EIP
int32_t offset = imm32();
trace(2, "run") << "call imm32 0x" << HEXWORD << offset << end();
push(EIP);
EIP += offset;
trace(2, "run") << "jumping to 0x" << HEXWORD << EIP << end();
break;
}
//:
:(scenario call_r32)
% Reg[ESP].u = 0x64;
% Reg[EBX].u = 0x000000a0;
# op ModRM SIB displacement immediate
ff d3 # call function offset at EBX (reg 3)
# next EIP is 3
+run: call to effective address
+run: effective address is reg 3
+run: decrementing ESP to 0x00000060
+run: pushing value 0x00000003
+run: jumping to 0x000000a3
:(before "End Op ff Subops")
case 2: { // call function pointer at r/m32
trace(2, "run") << "call to effective address" << end();
int32_t* offset = effective_address(modrm);
push(EIP);
EIP += *offset;
trace(2, "run") << "jumping to 0x" << HEXWORD << EIP << end();
break;
}
:(scenario call_mem_at_r32)
% Reg[ESP].u = 0x64;
% Reg[EBX].u = 0x10;
% SET_WORD_IN_MEM(0x10, 0x000000a0);
# op ModRM SIB displacement immediate
ff 13 # call function offset at *EBX (reg 3)
# next EIP is 3
+run: call to effective address
+run: effective address is mem at address 0x10 (reg 3)
+run: decrementing ESP to 0x00000060
+run: pushing value 0x00000003
+run: jumping to 0x000000a3
//:: ret
:(scenario ret)
% Reg[ESP].u = 0x60;
% SET_WORD_IN_MEM(0x60, 0x00000010);
# op ModRM SIB displacement immediate
c3
+run: return
+run: popping value 0x00000010
+run: jumping to 0x00000010
:(before "End Single-Byte Opcodes")
case 0xc3: { // return from a call
trace(2, "run") << "return" << end();
EIP = pop();
trace(2, "run") << "jumping to 0x" << HEXWORD << EIP << end();
break;
}