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Factor out x86 segment override prefix encoding, and also use it for VEX 

llvm-svn: 107942
This commit is contained in:
Bruno Cardoso Lopes 2010-07-09 00:38:14 +00:00
parent 21eed476e8
commit e6cc0d33bb
1 changed files with 33 additions and 18 deletions
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49
llvm/lib/Target/X86/X86MCCodeEmitter.cpp
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@ -129,10 +129,14 @@ public:
void EncodeInstruction(const MCInst &MI, raw_ostream &OS,
SmallVectorImpl<MCFixup> &Fixups) const;
void EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
void EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, int MemOperand,
const MCInst &MI, const TargetInstrDesc &Desc,
raw_ostream &OS) const;
void EmitSegmentOverridePrefix(uint64_t TSFlags, unsigned &CurByte,
int MemOperand, const MCInst &MI,
raw_ostream &OS) const;
void EmitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, int MemOperand,
const MCInst &MI, const TargetInstrDesc &Desc,
raw_ostream &OS) const;
@ -356,7 +360,8 @@ void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op,
/// EmitVEXOpcodePrefix - AVX instructions are encoded using a opcode prefix
/// called VEX.
void X86MCCodeEmitter::EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
const MCInst &MI, const TargetInstrDesc &Desc,
int MemOperand, const MCInst &MI,
const TargetInstrDesc &Desc,
raw_ostream &OS) const {
bool HasVEX_4V = false;
if ((TSFlags >> 32) & X86II::VEX_4V)
@ -509,6 +514,9 @@ void X86MCCodeEmitter::EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
assert(0 && "Not implemented!");
}
// Emit segment override opcode prefix as needed.
EmitSegmentOverridePrefix(TSFlags, CurByte, MemOperand, MI, OS);
// VEX opcode prefix can have 2 or 3 bytes
//
// 3 bytes:
@ -628,20 +636,11 @@ static unsigned DetermineREXPrefix(const MCInst &MI, uint64_t TSFlags,
return REX;
}
/// EmitOpcodePrefix - Emit all instruction prefixes prior to the opcode.
///
/// MemOperand is the operand # of the start of a memory operand if present. If
/// Not present, it is -1.
void X86MCCodeEmitter::EmitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
int MemOperand, const MCInst &MI,
const TargetInstrDesc &Desc,
/// EmitSegmentOverridePrefix - Emit segment override opcode prefix as needed
void X86MCCodeEmitter::EmitSegmentOverridePrefix(uint64_t TSFlags,
unsigned &CurByte, int MemOperand,
const MCInst &MI,
raw_ostream &OS) const {
// Emit the lock opcode prefix as needed.
if (TSFlags & X86II::LOCK)
EmitByte(0xF0, CurByte, OS);
// Emit segment override opcode prefix as needed.
switch (TSFlags & X86II::SegOvrMask) {
default: assert(0 && "Invalid segment!");
case 0:
@ -666,6 +665,23 @@ void X86MCCodeEmitter::EmitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
EmitByte(0x65, CurByte, OS);
break;
}
}
/// EmitOpcodePrefix - Emit all instruction prefixes prior to the opcode.
///
/// MemOperand is the operand # of the start of a memory operand if present. If
/// Not present, it is -1.
void X86MCCodeEmitter::EmitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
int MemOperand, const MCInst &MI,
const TargetInstrDesc &Desc,
raw_ostream &OS) const {
// Emit the lock opcode prefix as needed.
if (TSFlags & X86II::LOCK)
EmitByte(0xF0, CurByte, OS);
// Emit segment override opcode prefix as needed.
EmitSegmentOverridePrefix(TSFlags, CurByte, MemOperand, MI, OS);
// Emit the repeat opcode prefix as needed.
if ((TSFlags & X86II::Op0Mask) == X86II::REP)
@ -776,8 +792,7 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS,
if (!HasVEXPrefix)
EmitOpcodePrefix(TSFlags, CurByte, MemoryOperand, MI, Desc, OS);
else
// FIXME: Segment overrides??
EmitVEXOpcodePrefix(TSFlags, CurByte, MI, Desc, OS);
EmitVEXOpcodePrefix(TSFlags, CurByte, MemoryOperand, MI, Desc, OS);
unsigned char BaseOpcode = X86II::getBaseOpcodeFor(TSFlags);
unsigned SrcRegNum = 0;