From 84ed54f91e0dfec0355bdc723fa06fff9a57d089 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Wed, 8 Jan 2014 12:58:12 +0000 Subject: [x86] Fix JCXZ,JECXZ_32 for 16-bit mode JCXZ should have the 0x67 prefix only if we're in 32-bit mode, so make that appropriately conditional. And JECXZ needs the prefix instead. llvm-svn: 198757 --- llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp') diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp index e44574c31e2..d3879e6c4cf 100644 --- a/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp +++ b/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp @@ -1161,7 +1161,11 @@ void X86MCCodeEmitter::EmitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, // Emit the address size opcode prefix as needed. bool need_address_override; - if (TSFlags & X86II::AdSize) { + // The AdSize prefix is only for 32-bit and 64-bit modes; in 16-bit mode we + // need the address override only for JECXZ instead. Since it's only one + // instruction, we special-case it rather than introducing an AdSize16 bit. + if ((!is16BitMode() && TSFlags & X86II::AdSize) || + (is16BitMode() && MI.getOpcode() == X86::JECXZ_32)) { need_address_override = true; } else if (MemOperand == -1) { need_address_override = false; -- cgit v1.2.3