aboutsummaryrefslogtreecommitdiff
path: root/gas/doc
diff options
context:
space:
mode:
authorH.J. Lu <hjl.tools@gmail.com>2018-03-07 04:18:45 -0800
committerH.J. Lu <hjl.tools@gmail.com>2018-03-07 04:18:56 -0800
commit3ae729d5a4f63740ed9a778960b17c2912b0bbdd (patch)
treeb186f154a1e58be2c572eaeef8e593715736467b /gas/doc
parent52fe4420b771a0f3b4fc7c6535bbd6e9b279f775 (diff)
downloadbinutils-3ae729d5a4f63740ed9a778960b17c2912b0bbdd.zip
binutils-3ae729d5a4f63740ed9a778960b17c2912b0bbdd.tar.gz
binutils-3ae729d5a4f63740ed9a778960b17c2912b0bbdd.tar.bz2
x86: Rewrite NOP generation for fill and alignment
Rewrite NOP generation for fill and code alignment by: 1. Add a 11-byte NOP with another 0x66 prefix. 2. Remove the multi-byte NOP entries which consist of 2 instructions. 3. Select proper NOPs based on ISA and processor tuning. 4. Generate multiple NOPs with the longer NOPs first followed by the shorter NOP. 5. Use jump for larger NOP padding: a. > 8 bytes (2 NOPs) in 16-bit mode. b. > 14 bytes (2 NOPs) for older processors. c. > 77 bytes (7 NOPs) for newer processors. 6. Update MAX_MEM_FOR_RS_ALIGN_CODE to 4095. PR gas/22874 * config/tc-i386.c (f32_5): Removed. (f32_8): Likewise. (f32_9): Likewise. (f32_10): Likewise. (f32_11): Likewise. (f32_12): Likewise. (f32_13): Likewise. (f32_14): Likewise. (f16_5): Likewise. (f16_6): Likewise. (f16_7): Likewise. (f16_8): Likewise. (jump_31): Likewise. (alt64_11): Likewise. (alt64_patt): Likewise. (jump_disp8): New. (jump32_disp32): Likewise. (jump16_disp32): Likewise. (alt_11): Likewise. (f32_patt): Updated. (f16_patt): Likewise. (alt_patt): Add alt_11. (i386_align_code): Merged with ... (i386_generate_nops): This. Rewritten. (fits_in_imm7): Moved before i386_generate_nops. (fits_in_imm31): Likewise. * config/tc-i386.h (MAX_MEM_FOR_RS_ALIGN_CODE): Updated to 4095. (i386_align_code): Removed. (HANDLE_ALIGN): Rewritten with i386_generate_nops. * doc/as.texinfo: Update limits of control byte for x86 .nops directive. * testsuite/gas/i386/i386.exp: Run nops-7 and x86-64-nops-7. * gas/testsuite/gas/i386/noavx-3.l: Updated. * gas/testsuite/gas/i386/nop-1.d: Likewise. * gas/testsuite/gas/i386/nop-1.s: Likewise. * gas/testsuite/gas/i386/nop-2.d: Likewise. * gas/testsuite/gas/i386/nop-2.s: Likewise. * gas/testsuite/gas/i386/nop-3.d: Likewise. * gas/testsuite/gas/i386/nop-4.d: Likewise. * gas/testsuite/gas/i386/nop-5.d: Likewise. * gas/testsuite/gas/i386/nop-5.s: Likewise. * gas/testsuite/gas/i386/nop-6.d: Likewise. * gas/testsuite/gas/i386/nop-bad-1.l: Likewise. * gas/testsuite/gas/i386/nops-1-core2.d: Likewise. * gas/testsuite/gas/i386/nops-1-i386-i686.d: Likewise. * gas/testsuite/gas/i386/nops-1-i386.d: Likewise. * gas/testsuite/gas/i386/nops-1-i686.d: Likewise. * gas/testsuite/gas/i386/nops-1-k8.d: Likewise. * gas/testsuite/gas/i386/nops-1.d: Likewise. * gas/testsuite/gas/i386/nops-2-core2.d: Likewise. * gas/testsuite/gas/i386/nops-2-i386.d: Likewise. * gas/testsuite/gas/i386/nops-2.d: Likewise. * gas/testsuite/gas/i386/nops-3-i386.d: Likewise. * gas/testsuite/gas/i386/nops-3-i686.d: Likewise. * gas/testsuite/gas/i386/nops-3.d: Likewise. * gas/testsuite/gas/i386/nops-4-i386.d: Likewise. * gas/testsuite/gas/i386/nops-4-i686.d: Likewise. * gas/testsuite/gas/i386/nops-4.d: Likewise. * gas/testsuite/gas/i386/nops-4a-i686.d: Likewise. * gas/testsuite/gas/i386/nops-5-i686.d: Likewise. * gas/testsuite/gas/i386/nops-5.d: Likewise. * gas/testsuite/gas/i386/nops-6.d: Likewise. * gas/testsuite/gas/i386/nops16-1.d: Likewise. * gas/testsuite/gas/i386/x86-64-nop-1.d: Likewise. * gas/testsuite/gas/i386/x86-64-nop-2.d: Likewise. * gas/testsuite/gas/i386/x86-64-nop-5.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-1-core2.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-1-g64.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-1-k8.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-1-pentium.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-1.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-2.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-3.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-4-core2.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-4-k8.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-4.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-5-k8.d: Likewise. * gas/testsuite/gas/i386/x86-64-nops-5.d: Likewise. * gas/testsuite/gas/i386/ilp32/x86-64-nops-1-core2.d: Likewise. * gas/testsuite/gas/i386/ilp32/x86-64-nops-1-k8.d: Likewise. * gas/testsuite/gas/i386/ilp32/x86-64-nops-1-pentium.d: Likewise. * gas/testsuite/gas/i386/ilp32/x86-64-nops-1.d: Likewise. * gas/testsuite/gas/i386/ilp32/x86-64-nops-2.d: Likewise. * gas/testsuite/gas/i386/ilp32/x86-64-nops-3.d: Likewise. * gas/testsuite/gas/i386/ilp32/x86-64-nops-4-core2.d: Likewise. * gas/testsuite/gas/i386/ilp32/x86-64-nops-4-k8.d: Likewise. * gas/testsuite/gas/i386/ilp32/x86-64-nops-4.d: Likewise. * gas/testsuite/gas/i386/ilp32/x86-64-nops-5-k8.d: Likewise. * gas/testsuite/gas/i386/ilp32/x86-64-nops-5.d: Likewise. * gas/testsuite/gas/i386/nops-7.d: New file. * gas/testsuite/gas/i386/nops-7.s: Likewise. * gas/testsuite/gas/i386/x86-64-nops-7.d: Likewise.
Diffstat (limited to 'gas/doc')
-rw-r--r--gas/doc/as.texinfo7
1 files changed, 4 insertions, 3 deletions
diff --git a/gas/doc/as.texinfo b/gas/doc/as.texinfo
index f56515e..43286e9 100644
--- a/gas/doc/as.texinfo
+++ b/gas/doc/as.texinfo
@@ -6212,9 +6212,10 @@ zero.
Note: For Intel 80386 and AMD x86-64 targets, @var{control} specifies
the size limit of a no-op instruction. The valid values of @var{control}
-are between 0 and 8 for 16-bit mode, between 0 and 10 for 32-bit mode,
-between 0 and 11 for 64-bit mode. When 0 is used, the no-op instruction
-size limit is set to the maximum supported size.
+are between 0 and 4 in 16-bit mode, between 0 and 7 when tuning for
+older processors in 32-bit mode, between 0 and 11 in 64-bit mode or when
+tuning for newer processors in 32-bit mode. When 0 is used, the no-op
+instruction size limit is set to the maximum supported size.
@node Octa
@section @code{.octa @var{bignums}}