[PATCH 4/5] x86-64: Intel64 adjustments for conditional jumps
H.J. Lu
hjl.tools@gmail.com
Tue Jul 14 12:36:33 GMT 2020
On Tue, Jul 14, 2020 at 5:20 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 14.07.2020 14:18, Jan Beulich wrote:
> > On 14.07.2020 14:00, H.J. Lu wrote:
> >> On Tue, Jul 14, 2020 at 3:13 AM Jan Beulich <jbeulich@suse.com> wrote:
> >>> --- a/gas/testsuite/gas/i386/opcode-suffix.d
> >>> +++ b/gas/testsuite/gas/i386/opcode-suffix.d
> >>> @@ -305,22 +305,22 @@ Disassembly of section .text:
> >>> *[0-9a-f]+: 0f 77[ ]+emms[ ]+
> >>> *[0-9a-f]+: 0f 7e 90 90 90 90 90[ ]+movd[ ]+%mm2,-0x6f6f6f70\(%eax\)
> >>> *[0-9a-f]+: 0f 7f 90 90 90 90 90[ ]+movq[ ]+%mm2,-0x6f6f6f70\(%eax\)
> >>> - *[0-9a-f]+: 0f 80 90 90 90 90[ ]+jo[ ]+909094e2 <foo\+0x909094e2>
> >>> - *[0-9a-f]+: 0f 81 90 90 90 90[ ]+jno[ ]+909094e8 <foo\+0x909094e8>
> >>> - *[0-9a-f]+: 0f 82 90 90 90 90[ ]+jb[ ]+909094ee <foo\+0x909094ee>
> >>> - *[0-9a-f]+: 0f 83 90 90 90 90[ ]+jae[ ]+909094f4 <foo\+0x909094f4>
> >>> - *[0-9a-f]+: 0f 84 90 90 90 90[ ]+je[ ]+909094fa <foo\+0x909094fa>
> >>> - *[0-9a-f]+: 0f 85 90 90 90 90[ ]+jne[ ]+90909500 <foo\+0x90909500>
> >>> - *[0-9a-f]+: 0f 86 90 90 90 90[ ]+jbe[ ]+90909506 <foo\+0x90909506>
> >>> - *[0-9a-f]+: 0f 87 90 90 90 90[ ]+ja[ ]+9090950c <foo\+0x9090950c>
> >>> - *[0-9a-f]+: 0f 88 90 90 90 90[ ]+js[ ]+90909512 <foo\+0x90909512>
> >>> - *[0-9a-f]+: 0f 89 90 90 90 90[ ]+jns[ ]+90909518 <foo\+0x90909518>
> >>> - *[0-9a-f]+: 0f 8a 90 90 90 90[ ]+jp[ ]+9090951e <foo\+0x9090951e>
> >>> - *[0-9a-f]+: 0f 8b 90 90 90 90[ ]+jnp[ ]+90909524 <foo\+0x90909524>
> >>> - *[0-9a-f]+: 0f 8c 90 90 90 90[ ]+jl[ ]+9090952a <foo\+0x9090952a>
> >>> - *[0-9a-f]+: 0f 8d 90 90 90 90[ ]+jge[ ]+90909530 <foo\+0x90909530>
> >>> - *[0-9a-f]+: 0f 8e 90 90 90 90[ ]+jle[ ]+90909536 <foo\+0x90909536>
> >>> - *[0-9a-f]+: 0f 8f 90 90 90 90[ ]+jg[ ]+9090953c <foo\+0x9090953c>
> >>> + *[0-9a-f]+: 0f 80 90 90 90 90[ ]+jol[ ]+909094e2 <foo\+0x909094e2>
> >>> + *[0-9a-f]+: 0f 81 90 90 90 90[ ]+jnol[ ]+909094e8 <foo\+0x909094e8>
> >>> + *[0-9a-f]+: 0f 82 90 90 90 90[ ]+jbl[ ]+909094ee <foo\+0x909094ee>
> >>> + *[0-9a-f]+: 0f 83 90 90 90 90[ ]+jael[ ]+909094f4 <foo\+0x909094f4>
> >>> + *[0-9a-f]+: 0f 84 90 90 90 90[ ]+jel[ ]+909094fa <foo\+0x909094fa>
> >>> + *[0-9a-f]+: 0f 85 90 90 90 90[ ]+jnel[ ]+90909500 <foo\+0x90909500>
> >>> + *[0-9a-f]+: 0f 86 90 90 90 90[ ]+jbel[ ]+90909506 <foo\+0x90909506>
> >>> + *[0-9a-f]+: 0f 87 90 90 90 90[ ]+jal[ ]+9090950c <foo\+0x9090950c>
> >>> + *[0-9a-f]+: 0f 88 90 90 90 90[ ]+jsl[ ]+90909512 <foo\+0x90909512>
> >>> + *[0-9a-f]+: 0f 89 90 90 90 90[ ]+jnsl[ ]+90909518 <foo\+0x90909518>
> >>> + *[0-9a-f]+: 0f 8a 90 90 90 90[ ]+jpl[ ]+9090951e <foo\+0x9090951e>
> >>> + *[0-9a-f]+: 0f 8b 90 90 90 90[ ]+jnpl[ ]+90909524 <foo\+0x90909524>
> >>> + *[0-9a-f]+: 0f 8c 90 90 90 90[ ]+jll[ ]+9090952a <foo\+0x9090952a>
> >>> + *[0-9a-f]+: 0f 8d 90 90 90 90[ ]+jgel[ ]+90909530 <foo\+0x90909530>
> >>> + *[0-9a-f]+: 0f 8e 90 90 90 90[ ]+jlel[ ]+90909536 <foo\+0x90909536>
> >>> + *[0-9a-f]+: 0f 8f 90 90 90 90[ ]+jgl[ ]+9090953c <foo\+0x9090953c>
> >>> *[0-9a-f]+: 0f 90 80 90 90 90 90[ ]+seto[ ]+-0x6f6f6f70\(%eax\)
> >>> *[0-9a-f]+: 0f 91 80 90 90 90 90[ ]+setno[ ]+-0x6f6f6f70\(%eax\)
> >>> *[0-9a-f]+: 0f 92 80 90 90 90 90[ ]+setb[ ]+-0x6f6f6f70\(%eax\)
> >>
> >> There are instructions like jl and jnl. Will assembler properly
> >> handle `l' as a suffix here?
> >
> > j<cc> as well as jmp (with displacement) have No_lSuf set, so won't
> > accept l suffixes (same for the w one). Nevertheless already prior
> > to this change the disassembler will produce "jmpl" (and "jmpw").
> > IOW a disagreement between disassembler and assembler already exists.
We should avoid it as much as we can.
> >> If we do need to distinguish them, can we generate {disp32} pseudo prefix
> >> instead?
> >
> > We could, but then consistently for Jcc, JMP, and CALL. But how is
> > emitting a pseudo-prefix in line with the name of the controlling
> > command line option "-Msuffix"?
That works for me.
> FAOD to achieve consistency I think the preferred route would then
> be for the assembler to accept l and w suffixes for Jcc and JMP.
> Not sure though what fallout this may mean.
That could be quite messy. I think pseudo prefix is much less invasive.
--
H.J.
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