[LLVMdev] where is F7 opcode for TEST instruction on X86?

[Craig Topper]

If memory serves the Xi16, Xi32, and Xi64 types cause some magic inside of
BinOpMI_F(or classes it inherits from) to OR a 1 into the LSB of the opcode.


On Tue, Apr 22, 2014 at 6:45 AM, Jun Koi <junkoi2004 at gmail.com> wrote:

> hi,
>
> at the moment, TEST instruction is defined with 0xf7 opcode, as
> demonstrated below.
>
> $ echo "0xf7 0xc0 0x00 0x00 0x00 0x22"|./Release+Asserts/bin/llvm-mc
> -disassemble -arch=x86
>     .section    __TEXT,__text,regular,pure_instructions
>     testl    $570425344, %eax        ## imm = 0x22000000
>
> however, i cannot find anywhere this F7 opcode is defined in
> lib/Target/X86/X86InstrArithmetic.td.
> we only have TEST defined with F6 & other opcode like below.
>
> any hint please?
>
> thanks.
>
>
> let isCompare = 1 in {
>   let Defs = [EFLAGS] in {
>     let isCommutable = 1 in {
>       def TEST8rr  : BinOpRR_F<0x84, "test", Xi8 , X86testpat, MRMSrcReg>;
>       def TEST16rr : BinOpRR_F<0x84, "test", Xi16, X86testpat, MRMSrcReg>;
>       def TEST32rr : BinOpRR_F<0x84, "test", Xi32, X86testpat, MRMSrcReg>;
>       def TEST64rr : BinOpRR_F<0x84, "test", Xi64, X86testpat, MRMSrcReg>;
>     } // isCommutable
>
>     def TEST8rm    : BinOpRM_F<0x84, "test", Xi8 , X86testpat>;
>     def TEST16rm   : BinOpRM_F<0x84, "test", Xi16, X86testpat>;
>     def TEST32rm   : BinOpRM_F<0x84, "test", Xi32, X86testpat>;
>     def TEST64rm   : BinOpRM_F<0x84, "test", Xi64, X86testpat>;
>
>     def TEST8ri    : BinOpRI_F<0xF6, "test", Xi8 , X86testpat, MRM0r>;
>     def TEST16ri   : BinOpRI_F<0xF6, "test", Xi16, X86testpat, MRM0r>;
>     def TEST32ri   : BinOpRI_F<0xF6, "test", Xi32, X86testpat, MRM0r>;
>     def TEST64ri32 : BinOpRI_F<0xF6, "test", Xi64, X86testpat, MRM0r>;
>
>     def TEST8mi    : BinOpMI_F<"test", Xi8 , X86testpat, MRM0m, 0xF6>;
>     def TEST16mi   : BinOpMI_F<"test", Xi16, X86testpat, MRM0m, 0xF6>;
>     def TEST32mi   : BinOpMI_F<"test", Xi32, X86testpat, MRM0m, 0xF6>;
>     def TEST64mi32 : BinOpMI_F<"test", Xi64, X86testpat, MRM0m, 0xF6>;
>
>     // When testing the result of EXTRACT_SUBREG sub_8bit_hi, make sure the
>     // register class is constrained to GR8_NOREX.
>     let isPseudo = 1 in
>     def TEST8ri_NOREX : I<0, Pseudo, (outs), (ins GR8_NOREX:$src,
> i8imm:$mask),
>                           "", [], IIC_BIN_NONMEM>, Sched<[WriteALU]>;
>   } // Defs = [EFLAGS]
>
>   def TEST8i8    : BinOpAI<0xA8, "test", Xi8 , AL,
>                            "{$src, %al|al, $src}">;
>   def TEST16i16  : BinOpAI<0xA8, "test", Xi16, AX,
>                            "{$src, %ax|ax, $src}">;
>   def TEST32i32  : BinOpAI<0xA8, "test", Xi32, EAX,
>                            "{$src, %eax|eax, $src}">;
>   def TEST64i32  : BinOpAI<0xA8, "test", Xi64, RAX,
>                            "{$src, %rax|rax, $src}">;
> } // isCompare
>
>
>
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>


-- 
~Craig
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