diff options
Diffstat (limited to 'src/arch/x86/predecoder.hh')
| -rw-r--r-- | src/arch/x86/predecoder.hh | 65 |
1 files changed, 38 insertions, 27 deletions
diff --git a/src/arch/x86/predecoder.hh b/src/arch/x86/predecoder.hh index 371ce9db9..062025a61 100644 --- a/src/arch/x86/predecoder.hh +++ b/src/arch/x86/predecoder.hh @@ -70,8 +70,11 @@ namespace X86ISA class Predecoder { private: + //These are defined and documented in predecoder_tables.cc static const uint8_t Prefixes[256]; static const uint8_t UsesModRM[2][256]; + static const uint8_t ImmediateType[2][256]; + static const uint8_t ImmediateTypeToSize[3][10]; protected: ThreadContext * tc; @@ -193,10 +196,11 @@ namespace X86ISA break; case Rex: warn("Found Rex prefix %#x!\n", nextByte); + emi.rexPrefix = nextByte; offset++; break; case 0: - emi.twoByteOpcode = false; + emi.numOpcodes = 0; state = Opcode; break; default: @@ -204,20 +208,30 @@ namespace X86ISA } break; case Opcode: + emi.numOpcodes++; + assert(emi.numOpcodes < 2); if(nextByte == 0xf0) { warn("Found two byte opcode!\n"); - emi.twoByteOpcode = true; } else { + immediateCollected = 0; + displacementCollected = 0; + emi.immediate = 0; + emi.displacement = 0; + int immType = ImmediateType[ + emi.numOpcodes - 1][nextByte]; + if(0) //16 bit mode + immediateSize = ImmediateTypeToSize[0][immType]; + else if(!(emi.rexPrefix & 0x4)) //32 bit mode + immediateSize = ImmediateTypeToSize[1][immType]; + else //64 bit mode + immediateSize = ImmediateTypeToSize[2][immType]; warn("Found opcode %#x!\n", nextByte); - if (UsesModRM[emi.twoByteOpcode ? 1 : 0][nextByte]) { + if (UsesModRM[emi.numOpcodes - 1][nextByte]) { state = ModRM; - } else if(0 /* uses immediate */) { - //Figure out how big the immediate should be - immediateCollected = 0; - emi.immediate = 0; + } else if(immediateSize) { state = Immediate; } else { emiIsReady = true; @@ -231,21 +245,21 @@ namespace X86ISA if (0) {//in 16 bit mode //figure out 16 bit displacement size if(nextByte & 0xC7 == 0x06 || - nextByte & 0xC0 == 0x40) - displacementSize = 1; - else if(nextByte & 0xC7 == 0x80) + nextByte & 0xC0 == 0x80) displacementSize = 2; + else if(nextByte & 0xC0 == 0x40) + displacementSize = 1; else displacementSize = 0; } else { //figure out 32/64 bit displacement size - if(nextByte & 0xC7 == 0x06 || - nextByte & 0xC0 == 0x40) + if(nextByte & 0xC7 == 0x05 || + nextByte & 0xC0 == 0x80) displacementSize = 4; - else if(nextByte & 0xC7 == 0x80) + else if(nextByte & 0xC0 == 0x40) displacementSize = 2; else - displacementSize = 4; + displacementSize = 0; } //If there's an SIB, get that next. //There is no SIB in 16 bit mode. @@ -254,12 +268,8 @@ namespace X86ISA // && in 32/64 bit mode) state = SIB; } else if(displacementSize) { - displacementCollected = 0; - emi.displacement = 0; state = Displacement; } else if(immediateSize) { - immediateCollected = 0; - emi.immediate = 0; state = Immediate; } else { emiIsReady = true; @@ -272,12 +282,8 @@ namespace X86ISA warn("Found SIB byte %#x!\n", nextByte); offset++; if(displacementSize) { - displacementCollected = 0; - emi.displacement = 0; state = Displacement; } else if(immediateSize) { - immediateCollected = 0; - emi.immediate = 0; state = Immediate; } else { emiIsReady = true; @@ -306,6 +312,9 @@ namespace X86ISA emi.displacement |= partialDisp; //Update how many bytes we've collected. displacementCollected += toGet; + offset += toGet; + warn("Collecting %d byte displacement, got %d bytes!\n", + displacementSize, toGet); if(displacementSize == displacementCollected) { //Sign extend the displacement @@ -324,8 +333,6 @@ namespace X86ISA panic("Undefined displacement size!\n"); } if(immediateSize) { - immediateCollected = 0; - emi.immediate = 0; state = Immediate; } else { emiIsReady = true; @@ -350,11 +357,15 @@ namespace X86ISA //Mask off what we don't want partialDisp &= mask(toGet * 8); //Shift it over to overlay with our immediate. - partialDisp <<= displacementCollected; + partialDisp <<= immediateCollected; //Put it into our immediate - emi.displacement |= partialDisp; + emi.immediate |= partialDisp; //Update how many bytes we've collected. - displacementCollected += toGet; + immediateCollected += toGet; + offset += toGet; + warn("Collecting %d byte immediate, got %d bytes!\n", + immediateSize, toGet); + if(immediateSize == immediateCollected) { emiIsReady = true; |