Annotation of OpenXM_contrib/gmp/mpn/x86/k6/cross.pl, Revision 1.1.1.1
1.1 maekawa 1: #! /usr/bin/perl
2:
3: # Copyright (C) 2000 Free Software Foundation, Inc.
4: #
5: # This file is part of the GNU MP Library.
6: #
7: # The GNU MP Library is free software; you can redistribute it and/or modify
8: # it under the terms of the GNU Lesser General Public License as published
9: # by the Free Software Foundation; either version 2.1 of the License, or (at
10: # your option) any later version.
11: #
12: # The GNU MP Library is distributed in the hope that it will be useful, but
13: # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14: # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
15: # License for more details.
16: #
17: # You should have received a copy of the GNU Lesser General Public License
18: # along with the GNU MP Library; see the file COPYING.LIB. If not, write to
19: # the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
20: # MA 02111-1307, USA.
21:
22:
23: # Usage: cross.pl [filename.o]...
24: #
25: # Produce an annotated disassembly of the given object files, indicating
26: # certain code alignment and addressing mode problems afflicting K6 chips.
27: # "ZZ" is used on all annotations, so this can be searched for.
28: #
29: # With no arguments, all .o files corresponding to .asm files are processed.
30: # This is good in the mpn object directory of a k6*-*-* build.
31: #
32: # As far as fixing problems goes, any cache line crossing problems in loops
33: # get attention, but as a rule it's too tedious to rearrange code or slip in
34: # nops to fix every problem in setup or finishup code.
35: #
36: # Bugs:
37: #
38: # Instructions without mod/rm bytes or which are already vector decoded are
39: # unaffected by cache line boundary crossing, but not all of these have yet
40: # been put in as exceptions. All that occur in practice in GMP are present
41: # though.
42: #
43: # There's no messages for using the vector decoded addressing mode (%esi),
44: # but that mode is easy to avoid when coding.
45:
46: use strict;
47:
48: sub disassemble {
49: my ($file) = @_;
50: my ($addr,$b1,$b2,$b3, $prefix,$opcode,$modrm);
51:
52: open (IN, "objdump -Srfh $file |")
53: || die "Cannot open pipe from objdump\n";
54: while (<IN>) {
55: print;
56:
57: if (/^[ \t]*[0-9]+[ \t]+\.text[ \t]/ && /2\*\*([0-9]+)$/) {
58: if ($1 < 5) {
59: print "ZZ need at least 2**5 for predictable cache line crossing\n";
60: }
61: }
62:
63: if (/^[ \t]*([0-9a-f]*):[ \t]*([0-9a-f]+)[ \t]+([0-9a-f]+)[ \t]+([0-9a-f]+)/) {
64: ($addr,$b1,$b2,$b3) = ($1,$2,$3,$4);
65:
66: } elsif (/^[ \t]*([0-9a-f]*):[ \t]*([0-9a-f]+)[ \t]+([0-9a-f]+)/) {
67: ($addr,$b1,$b2,$b3) = ($1,$2,$3,'');
68:
69: } elsif (/^[ \t]*([0-9a-f]*):[ \t]*([0-9a-f]+)/) {
70: ($addr,$b1,$b2,$b3) = ($1,$2,'','');
71:
72: } else {
73: next;
74: }
75:
76: if ($b1 =~ /0f/) {
77: $prefix = $b1;
78: $opcode = $b2;
79: $modrm = $b3;
80: } else {
81: $prefix = '';
82: $opcode = $b1;
83: $modrm = $b2;
84: }
85:
86: # modrm of the form 00-xxx-100 with an 0F prefix is the problem case
87: # for K6 and pre-CXT K6-2
88: if ($prefix =~ /0f/
89: && $opcode !~ /^8/ # jcond disp32
90: && $modrm =~ /^[0-3][4c]/) {
91: print "ZZ ($file) >3 bytes to determine instruction length\n";
92: }
93:
94: # with just an opcode, starting 1f mod 20h
95: if ($addr =~ /[13579bdf]f$/
96: && $prefix !~ /0f/
97: && $opcode !~ /1[012345]/ # adc
98: && $opcode !~ /1[89abcd]/ # sbb
99: && $opcode !~ /68/ # push $imm32
100: && $opcode !~ /^7/ # jcond disp8
101: && $opcode !~ /a[89]/ # test+imm
102: && $opcode !~ /a[a-f]/ # stos/lods/scas
103: && $opcode !~ /b8/ # movl $imm32,%eax
104: && $opcode !~ /e[0123]/ # loop/loopz/loopnz/jcxz
105: && $opcode !~ /e[b9]/ # jmp disp8/disp32
106: && $opcode !~ /f[89abcd]/ # clc,stc,cli,sti,cld,std
107: && !($opcode =~ /f[67]/ # grp 1
108: && $modrm =~ /^[2367abef]/) # mul, imul, div, idiv
109: && $modrm !~ /^$/) {
110: print "ZZ ($file) opcode/modrm cross 32-byte boundary\n";
111: }
112:
113: # with an 0F prefix, anything starting at 1f mod 20h
114: if ($addr =~ /[13579bdf][f]$/
115: && $prefix =~ /0f/) {
116: print "ZZ ($file) prefix/opcode cross 32-byte boundary\n";
117: }
118:
119: # with an 0F prefix, anything with mod/rm starting at 1e mod 20h
120: if ($addr =~ /[13579bdf][e]$/
121: && $prefix =~ /0f/
122: && $opcode !~ /^8/ # jcond disp32
123: && $modrm !~ /^$/) {
124: print "ZZ ($file) prefix/opcode/modrm cross 32-byte boundary\n";
125: }
126: }
127: close IN || die "Error from objdump (or objdump not available)\n";
128: }
129:
130:
131: my @files;
132: if ($#ARGV >= 0) {
133: @files = @ARGV;
134: } else {
135: @files = glob "*.asm";
136: map {s/.asm/.o/} @files;
137: }
138:
139: foreach (@files) {
140: disassemble($_);
141: }
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