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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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17
utils/TableGen/X86DisassemblerTables.cpp
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@@ -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;