[PATCH 05/12] x86-64: adjust MOVQ to/from SReg attributes
H.J. Lu
hjl.tools@gmail.com
Fri Aug 5 23:00:39 GMT 2022
On Fri, Aug 5, 2022 at 5:22 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> It is unclear to me why the corresponding MOV (no Q suffix) can be
> issued without REX.W, but MOVQ has to have that prefix (bit). Add
> NoRex64 and in exchange drop Size64.
>
> --- a/gas/testsuite/gas/i386/x86-64-segment.l
> +++ b/gas/testsuite/gas/i386/x86-64-segment.l
> @@ -5,8 +5,15 @@
> 5 0002 8C18 mov %ds,\(%rax\)
> 6 0004 8E18 movw \(%rax\),%ds
> 7 0006 8E18 mov \(%rax\),%ds
> - 8 # test segment reg insns with REX
> - 9 0008 488CD8 movq %ds,%rax
> - 10 000b 488ED8 movq %rax,%ds
> - 11 # Force a good alignment.
> - 12 000e 0000 .p2align 4,0
> + 8 # test segment reg insns with avoided REX
> + 9 0008 8CD8 mov %ds,%rax
> + 10 000a 8CD8 movq %ds,%rax
> + 11 000c 8ED8 mov %rax,%ds
> + 12 000e 8ED8 movq %rax,%ds
> + 13 # test segment reg insns with REX
> + 14 0010 418CD8 mov %ds,%r8
> + 15 0013 418CD8 movq %ds,%r8
> + 16 0016 418ED8 mov %r8,%ds
> + 17 0019 418ED8 movq %r8,%ds
> + 18 # Force a good alignment.
> + 19 001c 0+ + *\.p2align 4,0
> --- a/gas/testsuite/gas/i386/x86-64-segment.s
> +++ b/gas/testsuite/gas/i386/x86-64-segment.s
> @@ -5,8 +5,15 @@
> mov %ds,(%rax)
> movw (%rax),%ds
> mov (%rax),%ds
> -# test segment reg insns with REX
> +# test segment reg insns with avoided REX
> + mov %ds,%rax
> movq %ds,%rax
> + mov %rax,%ds
> movq %rax,%ds
> +# test segment reg insns with REX
> + mov %ds,%r8
> + movq %ds,%r8
> + mov %r8,%ds
> + movq %r8,%ds
> # Force a good alignment.
> .p2align 4,0
> --- a/opcodes/i386-opc.tbl
> +++ b/opcodes/i386-opc.tbl
> @@ -148,7 +148,7 @@ movq, 0xb8, None, Cpu64, Size64|No_bSuf|
> // implementation defined value is zero).
> mov, 0x8c, None, 0, RegMem|No_bSuf|No_sSuf|No_qSuf|No_ldSuf|NoRex64, { SReg, Reg16|Reg32|Reg64 }
> mov, 0x8c, None, 0, D|Modrm|IgnoreSize|No_bSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { SReg, Word|Unspecified|BaseIndex }
> -movq, 0x8c, None, Cpu64, D|RegMem|Size64|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { SReg, Reg64 }
> +movq, 0x8c, None, Cpu64, D|RegMem|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|NoRex64, { SReg, Reg64 }
> mov, 0x8e, None, 0, Modrm|IgnoreSize|No_bSuf|No_sSuf|No_qSuf|No_ldSuf|NoRex64, { Reg16|Reg32|Reg64, SReg }
> // Move to/from control debug registers. In the 16 or 32bit modes
> // they are 32bit. In the 64bit mode they are 64bit.
>
OK.
Thanks.
--
H.J.
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