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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: }