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#!/usr/bin/perl
push(@INC,"perlasm","../../perlasm");
require "x86asm.pl";
require "cbc.pl";
&asm_init($ARGV[0],"bf-686.pl");
$BF_ROUNDS=16;
$BF_OFF=($BF_ROUNDS+2)*4;
$L="ecx";
$R="edx";
$P="edi";
$tot="esi";
$tmp1="eax";
$tmp2="ebx";
$tmp3="ebp";
&des_encrypt("BF_encrypt",1);
&des_encrypt("BF_decrypt",0);
&cbc("BF_cbc_encrypt","BF_encrypt","BF_decrypt",1,4,5,3,-1,-1);
&asm_finish();
&file_end();
sub des_encrypt
{
local($name,$enc)=@_;
&function_begin($name,"");
&comment("");
&comment("Load the 2 words");
&mov("eax",&wparam(0));
&mov($L,&DWP(0,"eax","",0));
&mov($R,&DWP(4,"eax","",0));
&comment("");
&comment("P pointer, s and enc flag");
&mov($P,&wparam(1));
&xor( $tmp1, $tmp1);
&xor( $tmp2, $tmp2);
# encrypting part
if ($enc)
{
&xor($L,&DWP(0,$P,"",0));
for ($i=0; $i<$BF_ROUNDS; $i+=2)
{
&comment("");
&comment("Round $i");
&BF_ENCRYPT($i+1,$R,$L,$P,$tot,$tmp1,$tmp2,$tmp3);
&comment("");
&comment("Round ".sprintf("%d",$i+1));
&BF_ENCRYPT($i+2,$L,$R,$P,$tot,$tmp1,$tmp2,$tmp3);
}
&xor($R,&DWP(($BF_ROUNDS+1)*4,$P,"",0));
&mov("eax",&wparam(0));
&mov(&DWP(0,"eax","",0),$R);
&mov(&DWP(4,"eax","",0),$L);
&function_end_A($name);
}
else
{
&xor($L,&DWP(($BF_ROUNDS+1)*4,$P,"",0));
for ($i=$BF_ROUNDS; $i>0; $i-=2)
{
&comment("");
&comment("Round $i");
&BF_ENCRYPT($i,$R,$L,$P,$tot,$tmp1,$tmp2,$tmp3);
&comment("");
&comment("Round ".sprintf("%d",$i-1));
&BF_ENCRYPT($i-1,$L,$R,$P,$tot,$tmp1,$tmp2,$tmp3);
}
&xor($R,&DWP(0,$P,"",0));
&mov("eax",&wparam(0));
&mov(&DWP(0,"eax","",0),$R);
&mov(&DWP(4,"eax","",0),$L);
&function_end_A($name);
}
&function_end_B($name);
}
sub BF_ENCRYPT
{
local($i,$L,$R,$P,$tot,$tmp1,$tmp2,$tmp3)=@_;
&rotr( $R, 16);
&mov( $tot, &DWP(&n2a($i*4),$P,"",0));
&movb( &LB($tmp1), &HB($R));
&movb( &LB($tmp2), &LB($R));
&rotr( $R, 16);
&xor( $L, $tot);
&mov( $tot, &DWP(&n2a($BF_OFF+0x0000),$P,$tmp1,4));
&mov( $tmp3, &DWP(&n2a($BF_OFF+0x0400),$P,$tmp2,4));
&movb( &LB($tmp1), &HB($R));
&movb( &LB($tmp2), &LB($R));
&add( $tot, $tmp3);
&mov( $tmp1, &DWP(&n2a($BF_OFF+0x0800),$P,$tmp1,4)); # delay
&xor( $tot, $tmp1);
&mov( $tmp3, &DWP(&n2a($BF_OFF+0x0C00),$P,$tmp2,4));
&add( $tot, $tmp3);
&xor( $tmp1, $tmp1);
&xor( $L, $tot);
# delay
}
sub n2a
{
sprintf("%d",$_[0]);
}
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