#! /usr/bin/perl# Copyright 2000, 2001 Free Software Foundation, Inc.## This file is part of the GNU MP Library.## The GNU MP Library is free software; you can redistribute it and/or modify# it under the terms of the GNU Lesser General Public License as published# by the Free Software Foundation; either version 2.1 of the License, or (at# your option) any later version.## The GNU MP Library is distributed in the hope that it will be useful, but# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public# License for more details.## You should have received a copy of the GNU Lesser General Public License# along with the GNU MP Library; see the file COPYING.LIB.  If not, write to# the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,# MA 02110-1301, USA.# Usage: cross.pl [filename.o]...## Produce an annotated disassembly of the given object files, indicating# certain code alignment and addressing mode problems afflicting K6 chips.# "ZZ" is used on all annotations, so this can be searched for.## With no arguments, all .o files corresponding to .asm files are processed.# This is good in the mpn object directory of a k6*-*-* build.## Code alignments of 8 bytes or more are handled.  When 32 is used, cache# line boundaries will fall in at offsets 0x20,0x40,etc and problems are# flagged at those locations.  When 16 is used, the line boundaries can also# fall at offsets 0x10,0x30,0x50,etc, depending where the file is loaded, so# problems are identified there too.  Likewise when 8 byte alignment is used# problems are flagged additionally at 0x08,0x18,0x28,etc.## Usually 32 byte alignment is used for k6 routines, but less is certainly# possible if through good luck, or a little tweaking, cache line crossing# problems can be avoided at the extra locations.## Bugs:## Instructions without mod/rm bytes or which are already vector decoded are# unaffected by cache line boundary crossing, but not all of these have yet# been put in as exceptions.  All that occur in practice in GMP are present# though.## There's no messages for using the vector decoded addressing mode (%esi),# but that's easy to avoid when coding.## Future:## Warn about jump targets that are poorly aligned (less than 2 instructions# before a cache line boundary).use strict;sub disassemble {    my ($file) = @_;    my ($addr,$b1,$b2,$b3, $prefix,$opcode,$modrm);    my $align;    open (IN, "objdump -Srfh $file |")	|| die "Cannot open pipe from objdump\n";    while (<IN>) {	print;	if (/^[ \t]*[0-9]+[ \t]+\.text[ \t]/ && /2\*\*([0-9]+)$/) {	    $align = 1 << $1;	    if ($align < 8) {		print "ZZ cross.pl cannot handle alignment < 2**3\n";		$align = 8	    }	}		if (/^[ \t]*([0-9a-f]*):[ \t]*([0-9a-f]+)[ \t]+([0-9a-f]+)[ \t]+([0-9a-f]+)/) {	    ($addr,$b1,$b2,$b3) = ($1,$2,$3,$4);	} elsif (/^[ \t]*([0-9a-f]*):[ \t]*([0-9a-f]+)[ \t]+([0-9a-f]+)/) {	    ($addr,$b1,$b2,$b3) = ($1,$2,$3,'');	} elsif (/^[ \t]*([0-9a-f]*):[ \t]*([0-9a-f]+)/) {	    ($addr,$b1,$b2,$b3) = ($1,$2,'','');	} else {	    next;	}	if ($b1 =~ /0f/) {	    $prefix = $b1;	    $opcode = $b2;	    $modrm = $b3;	} else {	    $prefix = '';	    $opcode = $b1;	    $modrm = $b2;	}	# modrm of the form 00-xxx-100 with an 0F prefix is the problem case	# for K6 and pre-CXT K6-2	if ($prefix =~ /0f/	    && $opcode !~ /^8/         # jcond disp32	    && $modrm =~ /^[0-3][4c]/) {	    print "ZZ ($file) >3 bytes to determine instruction length [K6]\n";	}	# with just an opcode, starting 1f mod 20h	if (($align==32 && $addr =~ /[13579bdf]f$/	     || $align==16 && $addr =~ /f$/	     || $align==8 && $addr =~ /[7f]$/)	    && $prefix !~ /0f/	    && $opcode !~ /1[012345]/ # adc	    && $opcode !~ /1[89abcd]/ # sbb	    && $opcode !~ /^4/        # inc/dec reg	    && $opcode !~ /^5/        # push/pop reg	    && $opcode !~ /68/        # push $imm32	    && $opcode !~ /^7/        # jcond disp8	    && $opcode !~ /a[89]/     # test+imm	    && $opcode !~ /a[a-f]/    # stos/lods/scas	    && $opcode !~ /b8/        # movl $imm32,%eax	    && $opcode !~ /d[0123]/   # rcl	    && $opcode !~ /e[0123]/   # loop/loopz/loopnz/jcxz	    && $opcode !~ /e8/        # call disp32	    && $opcode !~ /e[9b]/     # jmp disp32/disp8	    && $opcode !~ /f[89abcd]/ # clc,stc,cli,sti,cld,std	    && !($opcode =~ /f[67]/          # grp 1		 && $modrm =~ /^[2367abef]/) # mul, imul, div, idiv	    && $modrm !~ /^$/) {	    print "ZZ ($file) opcode/modrm cross 32-byte boundary\n";	}	# with an 0F prefix, anything starting at 1f mod 20h	if (($align==32 && $addr =~ /[13579bdf][f]$/	     || $align==16 && $addr =~ /f$/	     || $align==8 && $addr =~ /[7f]$/)	    && $prefix =~ /0f/	    && $opcode !~ /af/        # imul	    && $opcode !~ /a[45]/     # shldl	    && $opcode !~ /a[cd]/     # shrdl	    ) {	    print "ZZ ($file) prefix/opcode cross 32-byte boundary\n";	}	# with an 0F prefix, anything with mod/rm starting at 1e mod 20h	if (($align==32 && $addr =~ /[13579bdf][e]$/	     || $align==16 && $addr =~ /[e]$/	     || $align==8 && $addr =~ /[6e]$/)	    && $prefix =~ /0f/	     && $opcode !~ /^8/        # jcond disp32	     && $opcode !~ /af/        # imull reg,reg	     && $opcode !~ /a[45]/     # shldl	     && $opcode !~ /a[cd]/     # shrdl	    && $modrm !~ /^$/) {	    print "ZZ ($file) prefix/opcode/modrm cross 32-byte boundary\n";	}    }    close IN || die "Error from objdump (or objdump not available)\n";}my @files;if ($#ARGV >= 0) {    @files = @ARGV;} else {    @files = glob "*.asm";    map {s/.asm/.o/} @files;}foreach (@files)  {    disassemble($_);}