search for: is16bitmemoperand

On Fri, 2015-02-20 at 13:47 -0500, Rafael Espíndola wrote: > > Your task, should you choose to accept it, is to make it cope with other > > forms of relaxation where necessary. > > And if not, please open a bug :-) http://llvm.org/bugs/show_bug.cgi?id=22662 FWIW I could reproduce the 'movl foo, %ebx' one but a relative jump *was* using 16 bits (although gas uses 8):

...id X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op, unsigned BaseRegNo = BaseReg ? GetX86RegNum(Base) : -1U; + // 16-bit addressing forms of the ModR/M byte have a different encoding for + // the R/M field and are far more limited in which registers can be used. + if (Is16BitMemOperand(MI, Op)) { + if (BaseReg) { + // See Table 2-1 "16-Bit Addressing Forms with the ModR/M byte" + static const int R16Table[] = { 0, 0, 0, 7, 0, 6, 4, 5 }; + unsigned RMfield = R16Table[BaseRegNo]; + + assert(RMfield && "invalid 16-bit base register"...

...st MCInst > &MI, unsigned Op, > > unsigned BaseRegNo = BaseReg ? GetX86RegNum(Base) : -1U; > > + // 16-bit addressing forms of the ModR/M byte have a different encoding > for > + // the R/M field and are far more limited in which registers can be > used. > + if (Is16BitMemOperand(MI, Op)) { > + if (BaseReg) { > + // See Table 2-1 "16-Bit Addressing Forms with the ModR/M byte" > + static const int R16Table[] = { 0, 0, 0, 7, 0, 6, 4, 5 }; > + unsigned RMfield = R16Table[BaseRegNo]; > + > + assert(RMfield && "inva...