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Add a new compression type to ModRM table that detects when the memory modRM byte represent 8 instructions and the reg modRM byte represents up to 64 instructions. Reduces modRM table from 43k entreis to 25k entries. Based on a patch from Manman Ren.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163774 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Craig Topper 2012-09-13 05:45:42 +00:00
parent 7639f98c5f
commit 76b29b518d
3 changed files with 24 additions and 2 deletions
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4
lib/Target/X86/Disassembler/X86DisassemblerDecoder.c
View File

@ -138,6 +138,10 @@ static InstrUID decode(OpcodeType type,
if (modFromModRM(modRM) == 0x3)
return modRMTable[dec->instructionIDs+((modRM & 0x38) >> 3)+8];
return modRMTable[dec->instructionIDs+((modRM & 0x38) >> 3)];
case MODRM_SPLITMISC:
if (modFromModRM(modRM) == 0x3)
return modRMTable[dec->instructionIDs+(modRM & 0x3f)+8];
return modRMTable[dec->instructionIDs+((modRM & 0x38) >> 3)];
case MODRM_FULL:
return modRMTable[dec->instructionIDs+modRM];
}

5
lib/Target/X86/Disassembler/X86DisassemblerDecoderCommon.h
View File

@ -160,6 +160,10 @@ typedef uint16_t InstrUID;
* MODRM_SPLITRM - If the ModR/M byte is between 0x00 and 0xbf, the opcode
* corresponds to one instruction; otherwise, it corresponds to
* a different instruction.
* MODRM_SPLITMISC- If the ModR/M byte is between 0x00 and 0xbf, ModR/M byte
* divided by 8 is used to select instruction; otherwise, each
* value of the ModR/M byte could correspond to a different
* instruction.
* MODRM_SPLITREG - ModR/M byte divided by 8 is used to select instruction. This
corresponds to instructions that use reg field as opcode
* MODRM_FULL - Potentially, each value of the ModR/M byte could correspond
@ -169,6 +173,7 @@ typedef uint16_t InstrUID;
#define MODRMTYPES \
ENUM_ENTRY(MODRM_ONEENTRY) \
ENUM_ENTRY(MODRM_SPLITRM) \
ENUM_ENTRY(MODRM_SPLITMISC) \
ENUM_ENTRY(MODRM_SPLITREG) \
ENUM_ENTRY(MODRM_FULL)

17
utils/TableGen/X86DisassemblerTables.cpp
View File

@ -209,6 +209,7 @@ static ModRMDecisionType getDecisionType(ModRMDecision &decision) {
bool satisfiesOneEntry = true;
bool satisfiesSplitRM = true;
bool satisfiesSplitReg = true;
bool satisfiesSplitMisc = true;
for (unsigned index = 0; index < 256; ++index) {
if (decision.instructionIDs[index] != decision.instructionIDs[0])
@ -228,7 +229,7 @@ static ModRMDecisionType getDecisionType(ModRMDecision &decision) {
if (((index & 0xc0) != 0xc0) &&
(decision.instructionIDs[index] != decision.instructionIDs[index&0x38]))
satisfiesSplitReg = false;
satisfiesSplitMisc = false;
}
if (satisfiesOneEntry)
@ -237,9 +238,12 @@ static ModRMDecisionType getDecisionType(ModRMDecision &decision) {
if (satisfiesSplitRM)
return MODRM_SPLITRM;
if (satisfiesSplitReg)
if (satisfiesSplitReg && satisfiesSplitMisc)
return MODRM_SPLITREG;
if (satisfiesSplitMisc)
return MODRM_SPLITMISC;
return MODRM_FULL;
}
@ -332,6 +336,12 @@ void DisassemblerTables::emitModRMDecision(raw_ostream &o1, raw_ostream &o2,
for (unsigned index = 0xc0; index < 256; index += 8)
emitOneID(o1, i1, decision.instructionIDs[index], true);
break;
case MODRM_SPLITMISC:
for (unsigned index = 0; index < 64; index += 8)
emitOneID(o1, i1, decision.instructionIDs[index], true);
for (unsigned index = 0xc0; index < 256; ++index)
emitOneID(o1, i1, decision.instructionIDs[index], true);
break;
case MODRM_FULL:
for (unsigned index = 0; index < 256; ++index)
emitOneID(o1, i1, decision.instructionIDs[index], true);
@ -361,6 +371,9 @@ void DisassemblerTables::emitModRMDecision(raw_ostream &o1, raw_ostream &o2,
case MODRM_SPLITREG:
sEntryNumber += 16;
break;
case MODRM_SPLITMISC:
sEntryNumber += 8 + 64;
break;
case MODRM_FULL:
sEntryNumber += 256;
break;