From: "H.J. Lu" <hjl.tools@gmail.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: Binutils <binutils@sourceware.org>
Subject: Re: [PATCH v2] x86: also use D for MOVBE
Date: Tue, 2 Aug 2022 08:55:52 -0700 [thread overview]
Message-ID: <CAMe9rOr6j-nWgSq2i0PVMWJV7US6GY6wkR40kuHoio5tHQJv6Q@mail.gmail.com> (raw)
In-Reply-To: <e970f121-901b-adff-65b5-c4ab2f15bdb2@suse.com>
On Tue, Aug 2, 2022 at 6:38 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> First of all rename the meanwhile misleading Opcode_SIMD_FloatD, as it
> has also been used for KMOV* and BNDMOV. Then simplify the condition
> selecting which form if "reversing" to use - except for the MOV to/from
> control/debug/test registers all extended opcode space insns use bit 0
> (rather than bit 1) to indicate the direction (from/to memory) of an
> operation. With that, D can simply be set on the first of the two
> templates, while the other can be dropped.
> ---
> v2: Add comment.
>
> --- a/gas/config/tc-i386.c
> +++ b/gas/config/tc-i386.c
> @@ -3572,7 +3572,7 @@ build_vex_prefix (const insn_template *t
>
> if (i.tm.opcode_modifier.d)
> i.tm.base_opcode ^= (i.tm.base_opcode & 0xee) != 0x6e
> - ? Opcode_SIMD_FloatD : Opcode_SIMD_IntD;
> + ? Opcode_ExtD : Opcode_SIMD_IntD;
> else /* Use the next insn. */
> install_template (&t[1]);
> }
> @@ -6757,13 +6757,13 @@ match_template (char mnem_suffix)
> found_reverse_match = Opcode_VexW;
> goto check_operands_345;
> }
> - else if (operand_types[0].bitfield.xmmword
> - || operand_types[i.operands - 1].bitfield.xmmword
> - || operand_types[0].bitfield.class == RegMMX
> - || operand_types[i.operands - 1].bitfield.class == RegMMX
> - || is_any_vex_encoding(t))
> + else if (t->opcode_modifier.opcodespace != SPACE_BASE
> + && (t->opcode_modifier.opcodespace != SPACE_0F
> + /* MOV to/from CR/DR/TR, as an exception, follow
> + the base opcode space encoding model. */
> + || (t->base_opcode | 7) != 0x27))
> found_reverse_match = (t->base_opcode & 0xee) != 0x6e
> - ? Opcode_SIMD_FloatD : Opcode_SIMD_IntD;
> + ? Opcode_ExtD : Opcode_SIMD_IntD;
> else
> found_reverse_match = Opcode_D;
> if (t->opcode_modifier.floatr)
> --- a/opcodes/i386-opc.h
> +++ b/opcodes/i386-opc.h
> @@ -928,7 +928,7 @@ typedef struct insn_template
> unset if Regmem --> Reg. */
> #define Opcode_FloatR 0x8 /* Bit to swap src/dest for float insns. */
> #define Opcode_FloatD 0x400 /* Direction bit for float insns. */
> -#define Opcode_SIMD_FloatD 0x1 /* Direction bit for SIMD fp insns. */
> +#define Opcode_ExtD 0x1 /* Direction bit for extended opcode space insns. */
> #define Opcode_SIMD_IntD 0x10 /* Direction bit for SIMD int insns. */
> /* The next value is arbitrary, as long as it's non-zero and distinct
> from all other values above. */
> --- a/opcodes/i386-opc.tbl
> +++ b/opcodes/i386-opc.tbl
> @@ -161,8 +161,7 @@ movq, 0xf21, None, Cpu64, D|RegMem|Size6
> mov, 0xf24, None, Cpu386|CpuNo64, D|RegMem|IgnoreSize|No_bSuf|No_wSuf|No_sSuf|No_qSuf|No_ldSuf, { Test, Reg32 }
>
> // Move after swapping the bytes
> -movbe, 0x0f38f0, None, CpuMovbe, Modrm|No_bSuf|No_sSuf|No_ldSuf, { Word|Dword|Qword|Unspecified|BaseIndex, Reg16|Reg32|Reg64 }
> -movbe, 0x0f38f1, None, CpuMovbe, Modrm|No_bSuf|No_sSuf|No_ldSuf, { Reg16|Reg32|Reg64, Word|Dword|Qword|Unspecified|BaseIndex }
> +movbe, 0x0f38f0, None, CpuMovbe, D|Modrm|No_bSuf|No_sSuf|No_ldSuf, { Word|Dword|Qword|Unspecified|BaseIndex, Reg16|Reg32|Reg64 }
>
> // Move with sign extend.
> // "movsbl" & "movsbw" must not be unified into "movsb" to avoid
OK.
Thanks.
--
H.J.
prev parent reply other threads:[~2022-08-02 15:56 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-02 13:38 Jan Beulich
2022-08-02 15:55 ` H.J. Lu [this message]
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