x86: drop bogus Tbyte

Message ID 9f6f8888-4dc1-a6b0-0590-35fc8a276369@suse.com
State Accepted
Headers
Series x86: drop bogus Tbyte |

Checks

Context Check Description
snail/binutils-gdb-check success Github commit url

Commit Message

Jan Beulich Oct. 31, 2022, 10:18 a.m. UTC
  Prior to commit 1cb0ab18ad24 ("x86/Intel: restrict suffix derivation")
the Tbyte modifier on the FLDT and FSTPT templates was pointless, as
No_ldSuf would have prevented it being accepted. Due to the special
nature of LONG_DOUBLE_MNEM_SUFFIX said commit, however, has led to these
insns being accepted in Intel syntax mode even when "tbyte ptr" was
present. Restore original behavior by dropping Tbyte there. (Note that
these insns in principle should by marked AT&T syntax only, but since
they haven't been so far we probably shouldn't change that.)
  

Comments

H.J. Lu Oct. 31, 2022, 4:31 p.m. UTC | #1
On Mon, Oct 31, 2022 at 3:18 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> Prior to commit 1cb0ab18ad24 ("x86/Intel: restrict suffix derivation")
> the Tbyte modifier on the FLDT and FSTPT templates was pointless, as
> No_ldSuf would have prevented it being accepted. Due to the special
> nature of LONG_DOUBLE_MNEM_SUFFIX said commit, however, has led to these
> insns being accepted in Intel syntax mode even when "tbyte ptr" was
> present. Restore original behavior by dropping Tbyte there. (Note that
> these insns in principle should by marked AT&T syntax only, but since
> they haven't been so far we probably shouldn't change that.)
>
> --- a/opcodes/i386-opc.tbl
> +++ b/opcodes/i386-opc.tbl
> @@ -599,7 +599,7 @@ fld, 0xdb, 5, CpuFP, Modrm|No_bSuf|No_wS
>  fild, 0xdf, 0, CpuFP, Modrm|FloatMF|No_bSuf|No_wSuf|No_qSuf|No_ldSuf, { Word|Dword|Unspecified|BaseIndex }
>  fild, 0xdf, 5, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_ldSuf|NoRex64, { Qword|Unspecified|BaseIndex }
>  fildll, 0xdf, 5, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|ATTSyntax, { Unspecified|BaseIndex }
> -fldt, 0xdb, 5, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { Tbyte|Unspecified|BaseIndex }
> +fldt, 0xdb, 5, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { Unspecified|BaseIndex }
>  fbld, 0xdf, 4, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf, { Tbyte|Unspecified|BaseIndex }
>
>  // store (no pop)
> @@ -617,7 +617,7 @@ fstp, 0xdb, 7, CpuFP, Modrm|No_bSuf|No_w
>  fistp, 0xdf, 3, CpuFP, Modrm|FloatMF|No_bSuf|No_wSuf|No_qSuf|No_ldSuf, { Word|Dword|Unspecified|BaseIndex }
>  fistp, 0xdf, 7, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_ldSuf|NoRex64, { Qword|Unspecified|BaseIndex }
>  fistpll, 0xdf, 7, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|ATTSyntax, { Unspecified|BaseIndex }
> -fstpt, 0xdb, 7, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { Tbyte|Unspecified|BaseIndex }
> +fstpt, 0xdb, 7, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { Unspecified|BaseIndex }
>  fbstp, 0xdf, 6, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf, { Tbyte|Unspecified|BaseIndex }
>
>  // exchange %st<n> with %st0

OK.

Thanks.
  

Patch

--- a/opcodes/i386-opc.tbl
+++ b/opcodes/i386-opc.tbl
@@ -599,7 +599,7 @@  fld, 0xdb, 5, CpuFP, Modrm|No_bSuf|No_wS
 fild, 0xdf, 0, CpuFP, Modrm|FloatMF|No_bSuf|No_wSuf|No_qSuf|No_ldSuf, { Word|Dword|Unspecified|BaseIndex }
 fild, 0xdf, 5, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_ldSuf|NoRex64, { Qword|Unspecified|BaseIndex }
 fildll, 0xdf, 5, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|ATTSyntax, { Unspecified|BaseIndex }
-fldt, 0xdb, 5, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { Tbyte|Unspecified|BaseIndex }
+fldt, 0xdb, 5, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { Unspecified|BaseIndex }
 fbld, 0xdf, 4, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf, { Tbyte|Unspecified|BaseIndex }
 
 // store (no pop)
@@ -617,7 +617,7 @@  fstp, 0xdb, 7, CpuFP, Modrm|No_bSuf|No_w
 fistp, 0xdf, 3, CpuFP, Modrm|FloatMF|No_bSuf|No_wSuf|No_qSuf|No_ldSuf, { Word|Dword|Unspecified|BaseIndex }
 fistp, 0xdf, 7, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_ldSuf|NoRex64, { Qword|Unspecified|BaseIndex }
 fistpll, 0xdf, 7, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|ATTSyntax, { Unspecified|BaseIndex }
-fstpt, 0xdb, 7, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { Tbyte|Unspecified|BaseIndex }
+fstpt, 0xdb, 7, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { Unspecified|BaseIndex }
 fbstp, 0xdf, 6, CpuFP, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf, { Tbyte|Unspecified|BaseIndex }
 
 // exchange %st<n> with %st0