4080

subx: correct 'push' register. It gets its operand right from the
opcode, not a new modrm byte.

Have I misinterpreted any other instructions in this manner (`+rd` in
the Intel manual)?

2 files changed, 29 insertions, 17 deletions

diff --git a/html/subx/011direct_addressing.cc.html b/html/subx/011direct_addressing.cc.html
index dba0b3cf..a08f0e3f 100644
--- a/html/subx/011direct_addressing.cc.html
+++ b/html/subx/011direct_addressing.cc.html
@@ -286,25 +286,31 @@ if ('onhashchange' in window) {
 <span id="L221" class="LineNr">221 </span><span class="Special">% Reg[ESP].u = 0x64;</span>
 <span id="L222" class="LineNr">222 </span><span class="Special">% Reg[EBX].i = 10;</span>
 <span id="L223" class="LineNr">223 </span><span class="Comment"># op  ModRM   SIB   displacement  immediate</span>
-<span id="L224" class="LineNr">224 </span>  <span class="Constant">50</span>  <span class="PreProc">0</span><span class="Constant">3</span>                                      <span class="Comment"># push EBX (reg 3) to stack</span>
+<span id="L224" class="LineNr">224 </span>  <span class="Constant">53</span>                                          <span class="Comment"># push EBX (reg 3) to stack</span>
 <span id="L225" class="LineNr">225 </span><span class="traceContains">+run: push <a href='010core.cc.html#L17'>reg</a> 3</span>
 <span id="L226" class="LineNr">226 </span><span class="traceContains">+run: pushing value 0x0000000a</span>
 <span id="L227" class="LineNr">227 </span><span class="traceContains">+run: <a href='010core.cc.html#L11'>ESP</a> is now 0x00000060</span>
 <span id="L228" class="LineNr">228 </span><span class="traceContains">+run: <a href='003trace.cc.html#L74'>contents</a> at <a href='010core.cc.html#L11'>ESP</a>: 0x0000000a</span>
 <span id="L229" class="LineNr">229 </span>
 <span id="L230" class="LineNr">230 </span><span class="Delimiter">:(before &quot;End Single-Byte Opcodes&quot;)</span>
-<span id="L231" class="LineNr">231 </span><span class="Normal">case</span> <span class="Constant">0x50</span>: <span class="Delimiter">{</span>
-<span id="L232" class="LineNr">232 </span>  <span class="Normal">uint8_t</span> modrm = <a href='010core.cc.html#L214'>next</a><span class="Delimiter">();</span>
-<span id="L233" class="LineNr">233 </span>  <span class="Normal">uint8_t</span> <a href='010core.cc.html#L17'>reg</a> = modrm &amp; <span class="Constant">0x7</span><span class="Delimiter">;</span>
-<span id="L234" class="LineNr">234 </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 <a href='010core.cc.html#L17'>reg</a> &quot;</span> &lt;&lt; <a href='010core.cc.html#L232'>NUM</a><span class="Delimiter">(</span><a href='010core.cc.html#L17'>reg</a><span class="Delimiter">)</span> &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
-<span id="L235" class="LineNr">235 </span>  <span class="Normal">const</span> <span class="Normal">int32_t</span> val = Reg[reg]<span class="Delimiter">.</span>u<span class="Delimiter">;</span>
-<span id="L236" class="LineNr">236 </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;pushing value 0x&quot;</span> &lt;&lt; <a href='010core.cc.html#L230'>HEXWORD</a> &lt;&lt; val &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
-<span id="L237" class="LineNr">237 </span>  Reg[ESP]<span class="Delimiter">.</span>u -= <span class="Constant">4</span><span class="Delimiter">;</span>
-<span id="L238" class="LineNr">238 </span>  *<span class="Normal">reinterpret_cast</span>&lt;<span class="Normal">uint32_t</span>*&gt;<span class="Delimiter">(</span>&amp;Mem<span class="Delimiter">.</span>at<span class="Delimiter">(</span>Reg[ESP]<span class="Delimiter">.</span>u<span class="Delimiter">))</span> = val<span class="Delimiter">;</span>
-<span id="L239" class="LineNr">239 </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;ESP is now 0x&quot;</span> &lt;&lt; <a href='010core.cc.html#L230'>HEXWORD</a> &lt;&lt; Reg[ESP]<span class="Delimiter">.</span>u &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
-<span id="L240" class="LineNr">240 </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;contents at <a href='010core.cc.html#L11'>ESP</a>: 0x&quot;</span> &lt;&lt; <a href='010core.cc.html#L230'>HEXWORD</a> &lt;&lt; *<span class="Normal">reinterpret_cast</span>&lt;<span class="Normal">uint32_t</span>*&gt;<span class="Delimiter">(</span>&amp;Mem<span class="Delimiter">.</span>at<span class="Delimiter">(</span>Reg[ESP]<span class="Delimiter">.</span>u<span class="Delimiter">))</span> &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
-<span id="L241" class="LineNr">241 </span>  <span class="Identifier">break</span><span class="Delimiter">;</span>
-<span id="L242" class="LineNr">242 </span><span class="Delimiter">}</span>
+<span id="L231" class="LineNr">231 </span><span class="Normal">case</span> <span class="Constant">0x50</span>:
+<span id="L232" class="LineNr">232 </span><span class="Normal">case</span> <span class="Constant">0x51</span>:
+<span id="L233" class="LineNr">233 </span><span class="Normal">case</span> <span class="Constant">0x52</span>:
+<span id="L234" class="LineNr">234 </span><span class="Normal">case</span> <span class="Constant">0x53</span>:
+<span id="L235" class="LineNr">235 </span><span class="Normal">case</span> <span class="Constant">0x54</span>:
+<span id="L236" class="LineNr">236 </span><span class="Normal">case</span> <span class="Constant">0x55</span>:
+<span id="L237" class="LineNr">237 </span><span class="Normal">case</span> <span class="Constant">0x56</span>:
+<span id="L238" class="LineNr">238 </span><span class="Normal">case</span> <span class="Constant">0x57</span>: <span class="Delimiter">{</span>
+<span id="L239" class="LineNr">239 </span>  <span class="Normal">uint8_t</span> <a href='010core.cc.html#L17'>reg</a> = op &amp; <span class="Constant">0x7</span><span class="Delimiter">;</span>
+<span id="L240" class="LineNr">240 </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 <a href='010core.cc.html#L17'>reg</a> &quot;</span> &lt;&lt; <a href='010core.cc.html#L232'>NUM</a><span class="Delimiter">(</span><a href='010core.cc.html#L17'>reg</a><span class="Delimiter">)</span> &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
+<span id="L241" class="LineNr">241 </span>  <span class="Normal">const</span> <span class="Normal">int32_t</span> val = Reg[reg]<span class="Delimiter">.</span>u<span class="Delimiter">;</span>
+<span id="L242" class="LineNr">242 </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;pushing value 0x&quot;</span> &lt;&lt; <a href='010core.cc.html#L230'>HEXWORD</a> &lt;&lt; val &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
+<span id="L243" class="LineNr">243 </span>  Reg[ESP]<span class="Delimiter">.</span>u -= <span class="Constant">4</span><span class="Delimiter">;</span>
+<span id="L244" class="LineNr">244 </span>  *<span class="Normal">reinterpret_cast</span>&lt;<span class="Normal">uint32_t</span>*&gt;<span class="Delimiter">(</span>&amp;Mem<span class="Delimiter">.</span>at<span class="Delimiter">(</span>Reg[ESP]<span class="Delimiter">.</span>u<span class="Delimiter">))</span> = val<span class="Delimiter">;</span>
+<span id="L245" class="LineNr">245 </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;ESP is now 0x&quot;</span> &lt;&lt; <a href='010core.cc.html#L230'>HEXWORD</a> &lt;&lt; Reg[ESP]<span class="Delimiter">.</span>u &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
+<span id="L246" class="LineNr">246 </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;contents at <a href='010core.cc.html#L11'>ESP</a>: 0x&quot;</span> &lt;&lt; <a href='010core.cc.html#L230'>HEXWORD</a> &lt;&lt; *<span class="Normal">reinterpret_cast</span>&lt;<span class="Normal">uint32_t</span>*&gt;<span class="Delimiter">(</span>&amp;Mem<span class="Delimiter">.</span>at<span class="Delimiter">(</span>Reg[ESP]<span class="Delimiter">.</span>u<span class="Delimiter">))</span> &lt;&lt; <a href='003trace.cc.html#L184'>end</a><span class="Delimiter">();</span>
+<span id="L247" class="LineNr">247 </span>  <span class="Identifier">break</span><span class="Delimiter">;</span>
+<span id="L248" class="LineNr">248 </span><span class="Delimiter">}</span>
 </pre>
 </body>
 </html>
diff --git a/subx/011direct_addressing.cc b/subx/011direct_addressing.cc
index 2defcfec..827ce41e 100644
--- a/subx/011direct_addressing.cc
+++ b/subx/011direct_addressing.cc
@@ -221,16 +221,22 @@ case 0x89: {  // copy r32 to r/m32
 % Reg[ESP].u = 0x64;
 % Reg[EBX].i = 10;
 # op  ModRM   SIB   displacement  immediate
-  50  03                                      # push EBX (reg 3) to stack
+  53                                          # push EBX (reg 3) to stack
 +run: push reg 3
 +run: pushing value 0x0000000a
 +run: ESP is now 0x00000060
 +run: contents at ESP: 0x0000000a
 
 :(before "End Single-Byte Opcodes")
-case 0x50: {
-  uint8_t modrm = next();
-  uint8_t reg = modrm & 0x7;
+case 0x50:
+case 0x51:
+case 0x52:
+case 0x53:
+case 0x54:
+case 0x55:
+case 0x56:
+case 0x57: {
+  uint8_t reg = op & 0x7;
   trace(2, "run") << "push reg " << NUM(reg) << end();
   const int32_t val = Reg[reg].u;
   trace(2, "run") << "pushing value 0x" << HEXWORD << val << end();