This is the mail archive of the
binutils@sourceware.org
mailing list for the binutils project.
Re: [PATCH] x86-64: don't allow use of %axl as accumulator
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Jan Beulich <JBeulich at suse dot com>
- Cc: Binutils <binutils at sourceware dot org>
- Date: Fri, 10 Nov 2017 05:27:15 -0800
- Subject: Re: [PATCH] x86-64: don't allow use of %axl as accumulator
- Authentication-results: sourceware.org; auth=none
- References: <5A05AEA1020000780018DEE0@prv-mh.provo.novell.com>
On Fri, Nov 10, 2017 at 4:50 AM, Jan Beulich <JBeulich@suse.com> wrote:
> Just like %cxl can't be used as shift count register. Otherwise for
> consistency %cxl would need to gain "ShiftCount" and use of both ought
> to properly cause REX prefixes to be emitted.
There are no good testcases for
axl, Reg8|Acc|Byte, RegRex64, 0, Dw2Inval, Dw2Inval
cxl, Reg8, RegRex64, 1, Dw2Inval, Dw2Inval
dxl, Reg8, RegRex64, 2, Dw2Inval, Dw2Inval
bxl, Reg8, RegRex64, 3, Dw2Inval, Dw2Inval
bpl, Reg8, RegRex64, 5, Dw2Inval, Dw2Inval
I am not sure if the whole thing is handled correctly. If we want to change
them, we should make sure that they work correctly.
> gas/
> 2017-11-10 Jan Beulich <jbeulich@suse.com>
>
> * testsuite/gas/i386/x86-64-reg-bad.{s,l}: New.
> * testsuite/gas/i386/i386.exp: Run new test.
>
> opcodes/
> 2017-11-10 Jan Beulich <jbeulich@suse.com>
>
> * i386-reg.tbl (axl): Remove Acc and Byte.
> * i386-tbl.h: Re-generate.
>
> --- 2017-11-10/gas/testsuite/gas/i386/i386.exp
> +++ 2017-11-10/gas/testsuite/gas/i386/i386.exp
> @@ -628,6 +628,7 @@ if [expr ([istarget "i*86-*-*"] || [ista
> run_dump_test "x86-64-mem"
> run_dump_test "x86-64-mem-intel"
> run_dump_test "x86-64-reg"
> + run_list_test "x86-64-reg-bad" "-al"
> run_dump_test "x86-64-reg-intel"
> run_dump_test "x86-64-sib"
> run_dump_test "x86-64-sib-intel"
> --- 2017-11-10/gas/testsuite/gas/i386/x86-64-reg-bad.l
> +++ 2017-11-10/gas/testsuite/gas/i386/x86-64-reg-bad.l
> @@ -0,0 +1,18 @@
> +.*: Assembler messages:
> +.*:4: Error: .* mismatch for `movabs'
> +.*:6: Error: .* mismatch for `div'
> +.*:7: Error: .* mismatch for `in'
> +.*:8: Error: .* mismatch for `lods'
> +.*:9: Error: .* mismatch for `shl'
> +GAS LISTING .*
> +
> +
> +[ ]*[1-9][0-9]*[ ]+\# Check %axl / %cxl aren't permitted as accumulator / shift count
> +[ ]*[1-9][0-9]*[ ]+\.text
> +[ ]*[1-9][0-9]*[ ]+reg:
> +[ ]*[1-9][0-9]*[ ]+movabs -1, %axl
> +[ ]*[1-9][0-9]*[ ]+\?* 4080C001[ ]+add \$1, %axl
> +[ ]*[1-9][0-9]*[ ]+div %bl, %axl
> +[ ]*[1-9][0-9]*[ ]+in %dx, %axl
> +[ ]*[1-9][0-9]*[ ]+lods \(%rsi\), %axl
> +[ ]*[1-9][0-9]*[ ]+shl %cxl, %eax
> --- 2017-11-10/gas/testsuite/gas/i386/x86-64-reg-bad.s
> +++ 2017-11-10/gas/testsuite/gas/i386/x86-64-reg-bad.s
> @@ -0,0 +1,9 @@
> +# Check %axl / %cxl aren't permitted as accumulator / shift count
> + .text
> +reg:
> + movabs -1, %axl
> + add $1, %axl
> + div %bl, %axl
> + in %dx, %axl
> + lods (%rsi), %axl
> + shl %cxl, %eax
> --- 2017-11-10/opcodes/i386-reg.tbl
> +++ 2017-11-10/opcodes/i386-reg.tbl
> @@ -29,7 +29,7 @@ ah, Reg8, 0, 4, Dw2Inval, Dw2Inval
> ch, Reg8, 0, 5, Dw2Inval, Dw2Inval
> dh, Reg8, 0, 6, Dw2Inval, Dw2Inval
> bh, Reg8, 0, 7, Dw2Inval, Dw2Inval
> -axl, Reg8|Acc|Byte, RegRex64, 0, Dw2Inval, Dw2Inval
> +axl, Reg8, RegRex64, 0, Dw2Inval, Dw2Inval
> cxl, Reg8, RegRex64, 1, Dw2Inval, Dw2Inval
> dxl, Reg8, RegRex64, 2, Dw2Inval, Dw2Inval
> bxl, Reg8, RegRex64, 3, Dw2Inval, Dw2Inval
>
>
--
H.J.