- switch (Desc->TSFlags & X86II::FormMask) {
- case X86II::MRMInitReg:
- if (isX86_64ExtendedReg(MI.getOperand(0)))
- REX |= (1 << 0) | (1 << 2);
- break;
- case X86II::MRMSrcReg: {
- if (isX86_64ExtendedReg(MI.getOperand(0)))
- REX |= 1 << 2;
- i = isTwoAddr ? 2 : 1;
- for (unsigned e = NumOps; i != e; ++i) {
- const MachineOperand& MO = MI.getOperand(i);
- if (isX86_64ExtendedReg(MO))
- REX |= 1 << 0;
- }
- break;
- }
- case X86II::MRMSrcMem: {
- if (isX86_64ExtendedReg(MI.getOperand(0)))
- REX |= 1 << 2;
- unsigned Bit = 0;
- i = isTwoAddr ? 2 : 1;
- for (; i != NumOps; ++i) {
- const MachineOperand& MO = MI.getOperand(i);
- if (MO.isRegister()) {
- if (isX86_64ExtendedReg(MO))
- REX |= 1 << Bit;
- Bit++;
- }
- }
- break;
- }
- case X86II::MRM0m: case X86II::MRM1m:
- case X86II::MRM2m: case X86II::MRM3m:
- case X86II::MRM4m: case X86II::MRM5m:
- case X86II::MRM6m: case X86II::MRM7m:
- case X86II::MRMDestMem: {
- unsigned e = isTwoAddr ? 5 : 4;
- i = isTwoAddr ? 1 : 0;
- if (NumOps > e && isX86_64ExtendedReg(MI.getOperand(e)))
- REX |= 1 << 2;
- unsigned Bit = 0;
- for (; i != e; ++i) {
- const MachineOperand& MO = MI.getOperand(i);
- if (MO.isRegister()) {
- if (isX86_64ExtendedReg(MO))
- REX |= 1 << Bit;
- Bit++;
- }
- }
- break;
- }
- default: {
- if (isX86_64ExtendedReg(MI.getOperand(0)))
- REX |= 1 << 0;
- i = isTwoAddr ? 2 : 1;
- for (unsigned e = NumOps; i != e; ++i) {
- const MachineOperand& MO = MI.getOperand(i);
- if (isX86_64ExtendedReg(MO))
- REX |= 1 << 2;
- }
- break;
- }
- }
+ // Emit segment override opcode prefix as needed.
+ switch (Desc->TSFlags & X86II::SegOvrMask) {
+ case X86II::FS:
+ MCE.emitByte(0x64);
+ break;
+ case X86II::GS:
+ MCE.emitByte(0x65);
+ break;
+ default: assert(0 && "Invalid segment!");
+ case 0: break; // No segment override!