Hi,
in X86InstrArithmetic.td, we have LEA16r defined as:
def LEA16r : I<0x8D, MRMSrcMem,
(outs GR16:$dst), (ins i32mem:$src),
“lea{w}\t{$src|$dst}, {$dst|$src}”, , IIC_LEA_16>, OpSize16;
Please correct me if I am wrong, but I think “ins i32mem” should be “ins i16mem” because this is about 16bit register?
So is this a bug?
Thanks,
Jun
Hi Jun,
def LEA16r : I<0x8D, MRMSrcMem,
(outs GR16:$dst), (ins i32mem:$src),
"lea{w}\t{$src|$dst}, {$dst|$src}", , IIC_LEA_16>,
OpSize16;Please correct me if I am wrong, but I think "ins i32mem" should be "ins
i16mem" because this is about 16bit register?
I think there's something going on here, but it's probably more
complicated than that. The lea instruction just calculates an address,
so the resulting pointer doesn't really *have* a size.
Binutils seems to handle this reasonably by omitting the "dword
ptr"/"word ptr" part entirely when printing: "lea ax, [eax]" instead
of "mov ax, word ptr [eax]". The assembler accepts all variants, which
may or may not be a good choice.
Cheers.
Tim.
yes, i think this is a good idea. but then how can i modify LEA16r above to
eliminate "dword ptr" part?
thanks,
Jun
Hi Jun,
yes, i think this is a good idea. but then how can i modify LEA16r above to
eliminate "dword ptr" part?
I can't see an existing X86MemOperand with this property, so you'll
probably have to create a new one near the top of X86InstrInfo.td
(~line 332) and then use that. The PrintMethod should be reasonably
easy to implement.
Cheers.
Tim.
Oh right, now I can see where to modify.
Is a patch for this part welcome?
Thanks,
Jun
Hi Jun,