Scaffolding for 32-bit ModRM decoding

modules/pcjs/bin/x86gen.js

@@ -75,6 +75,9 @@ var w, sError = "";
 var fGenMods = true;
 var sEAFuncs = "";
 
+var aBase  = ["EAX", "ECX", "EDX", "EBX", "ESP",  "EBP", "ESI", "EDI"];
+var aIndex = ["EAX", "ECX", "EDX", "EBX", "none", "EBP", "ESI", "EDI"];
+
 if (!fGenMods) {
 
     var sOps = "", cOps = 0;
@@ -256,11 +259,37 @@ else {
         }
     }
 
+    sContainer = "X86ModSIB" + ".aOpModSIB";
+
+    print(sContainer + " = [");
+    for (var sib = 0x00; sib <= 0xff && !sError; sib++) {
+        genSIB(sib);
+    }
+    print("];\n");
+
     if (sEAFuncs) {
         print("var X86Mods = {\n" + sEAFuncs + "};\n");
     }
 }
 
+function genSIB(sib) {
+    var scale = (sib >> 6);
+    var index = (sib >> 3) & 0x7;
+    var base = (sib & 0x7);
+    var sFunc = "opModSIB" + toHex(sib, 2);
+    print("    /**");
+    print("     * " + sFunc + "(): scale=" + toBin(scale, 2) + " (" + toHex(1 << scale, 1) + ")  index=" + toBin(index, 3) + " (" + aIndex[index] + ")  base=" + toBin(base, 3) + " (" + (base == 5? "mod? EBP : disp32)" : aBase[base] + ")"));
+    print("     *");
+    print("     * @this {X86CPU}");
+    print("     * @param {number} mod");
+    print("     */");
+    print("    function " + sFunc + "(mod) {");
+    var sBase = (base == 5? "(mod? this.reg" + aBase[base] + " : this.getIPWord())" : "this.reg" + aBase[base]);
+    if (index != 4) sBase += " + (this.reg" + (aIndex[index] + " << " + scale) + ")";
+    print("        return " + sBase + ";");
+    print("    }" + (sib < 255? "," : ""));
+}
+
 function genMode(a, d, w, mrm, sGroup, sRO) {
     var mod = (mrm >> 6);
     var reg = (mrm >> 3) & 0x7;
@@ -680,7 +709,7 @@ function genMode(a, d, w, mrm, sGroup, sRO) {
                 nCycles = "this.CYCLES.nEACyclesBase";
                 break;
             case 4:
-                sModAddr = "this.getSIB()";
+                sModAddr = "this.getSIB(0)";
                 sModFunc = "SIB";
                 nCycles = "this.CYCLES.nEACyclesBase";
                 break;
@@ -727,7 +756,7 @@ function genMode(a, d, w, mrm, sGroup, sRO) {
                 nCycles = "this.CYCLES.nEACyclesBaseDisp";
                 break;
             case 4:
-                sModAddr = "this.getSIB() + this.getIPDisp()";
+                sModAddr = "this.getSIB(1) + this.getIPDisp()";
                 sModFunc = "SIBD8";
                 nCycles = "this.CYCLES.nEACyclesBaseDisp";
                 break;
@@ -774,7 +803,7 @@ function genMode(a, d, w, mrm, sGroup, sRO) {
                 nCycles = "this.CYCLES.nEACyclesBaseDisp";
                 break;
             case 4:
-                sModAddr = "this.getSIB() + this.getIPWord()";
+                sModAddr = "this.getSIB(2) + this.getIPWord()";
                 sModFunc = "SIBD32";
                 nCycles = "this.CYCLES.nEACyclesBaseDisp";
                 break;
@@ -917,7 +946,7 @@ function genMode(a, d, w, mrm, sGroup, sRO) {
         return null;
     }
 
-    sOpMod = "opMod" + aOpPrefix[w] + aAddrPrefix[a] + (sGroup? sGroup + (sRO? sRO : "") : aDst[d]) + toHex(mrm, 2);
+    sOpMod = "opMod" + aAddrPrefix[a] + (sGroup? sGroup + (sRO? sRO : "") : aDst[d]) + aSize[w] + toHex(mrm, 2);
 
     var sTemp = aSize[w].charAt(0).toLowerCase();
 
@@ -926,7 +955,7 @@ function genMode(a, d, w, mrm, sGroup, sRO) {
          * Use this to generate ModRM decoders that accept an array (ie, "group") of functions, and pass along an implied argument as well
          */
         if (sRO && reg != 7) {
-            sOpMod = "opMod" + aSize[w] + aAddrPrefix[a] + (sGroup? sGroup : aDst[d]) + toHex(mrm, 2);
+            sOpMod = "opMod" + aAddrPrefix[a] + (sGroup? sGroup : aDst[d]) + aSize[w] + toHex(mrm, 2);
             return sOpMod;
         }
 
@@ -1023,7 +1052,7 @@ function genMode(a, d, w, mrm, sGroup, sRO) {
         if (mod == 3 && !d) {
             var mrmPrime = (mod << 6) | (r_m << 3) | reg;
             print("    X86Mod" + aOpPrefix[w] + aAddrPrefix[a] + ".aOpModReg[0x" + toHex(mrmPrime, 2) + "],");
-            sOpMod = "opMod" + aOpPrefix[w] + aAddrPrefix[a] + aDst[1] + toHex(mrmPrime, 2);
+            sOpMod = "opMod" + aAddrPrefix[a] + aDst[1] + aSize[w] + toHex(mrmPrime, 2);
             return sOpMod;
         }
 

modules/pcjs/lib/.jshintrc

@@ -20,6 +20,7 @@
         "FATARRAYS": true,
         "TYPEDARRAYS": true,
         "SAMPLER": true,
+        "BACKTRACK": true,
         "Component": true,
         "State": true,
         "Bus": true,
@@ -43,7 +44,11 @@
         "X86CPU": true,
         "X86Grps": true,
         "X86Help": true,
-        "X86Mods": true,
+        "X86ModB": true,
+        "X86ModW": true,
+        "X86ModB32": true,
+        "X86ModW32": true,
+        "X86ModSIB": true,
         "X86OpXX": true,
         "X86Op0F": true,
         "str": true,

modules/pcjs/lib/x86cpu.js

@@ -46,6 +46,9 @@ if (typeof module !== 'undefined') {
     var X86Help     = require("./x86help");
     var X86ModB     = require("./x86modb");
     var X86ModW     = require("./x86modw");
+    var X86ModB32   = require("./x86modb32");
+    var X86ModW32   = require("./x86modw32");
+    var X86ModSIB   = require("./x86modsib");
     var X86OpXX     = require("./x86opxx");
     var X86Op0F     = require("./x86op0f");
 }
@@ -2318,7 +2321,7 @@ X86CPU.prototype.getIPByte = function()
 {
     var b = (PREFETCH? this.getBytePrefetch(this.regLIP) : this.getByte(this.regLIP));
     if (BACKTRACK) this.bus.updateBackTrackCode(this.regLIP, this.backTrack.btiMemLo);
-    this.regLIP = this.segCS.base + (this.regEIP = (this.regEIP + 1) & 0xffff);   // this.advanceIP(1)
+    this.regLIP = this.segCS.base + (this.regEIP = (this.regEIP + 1) & 0xffff); // this.advanceIP(1)
     return b;
 };
 
@@ -2332,7 +2335,7 @@ X86CPU.prototype.getIPDisp = function()
 {
     var b = ((PREFETCH? this.getBytePrefetch(this.regLIP) : this.getByte(this.regLIP)) << 24) >> 24;
     if (BACKTRACK) this.bus.updateBackTrackCode(this.regLIP, this.backTrack.btiMemLo);
-    this.regLIP = this.segCS.base + (this.regEIP = (this.regEIP + 1) & 0xffff);   // this.advanceIP(1)
+    this.regLIP = this.segCS.base + (this.regEIP = (this.regEIP + 1) & 0xffff); // this.advanceIP(1)
     return b & 0xffff;
 };
 
@@ -2349,10 +2352,24 @@ X86CPU.prototype.getIPWord = function()
         this.bus.updateBackTrackCode(this.regLIP, this.backTrack.btiMemLo);
         this.bus.updateBackTrackCode(this.regLIP + 1, this.backTrack.btiMemHi);
     }
-    this.regLIP = this.segCS.base + (this.regEIP = (this.regEIP + 2) & 0xffff);   // this.advanceIP(2)
+    this.regLIP = this.segCS.base + (this.regEIP = (this.regEIP + 2) & 0xffff); // this.advanceIP(2)
     return w;
 };
 
+/**
+ * getSIB(mod)
+ *
+ * @this {X86CPU}
+ * @param {number} mod
+ * @return {number}
+ */
+X86CPU.prototype.getSIB = function(mod)
+{
+    var b = PREFETCH? this.getBytePrefetch(this.regLIP) : this.getByte(this.regLIP);
+    if (BACKTRACK) this.bus.updateBackTrackCode(this.regLIP, this.backTrack.btiMemLo);
+    return X86ModSIB.aOpModSIB[b].call(this, mod);
+};
+
 /**
  * popWord()
  *