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#!/usr/local/bin/perl
#
# The inner loop instruction sequence and the IP/FP modifications are from
# Svend Olaf Mikkelsen <svolaf@inet.uni-c.dk>
# I've added the stuff needed for crypt() but I've not worried about making
# things perfect.
#
$0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1;
push(@INC,"${dir}","${dir}../../perlasm");
require "x86asm.pl";
&asm_init($ARGV[0],"crypt586.pl");
$L="edi";
$R="esi";
&external_label("DES_SPtrans");
&fcrypt_body("fcrypt_body");
&asm_finish();
sub fcrypt_body
{
local($name,$do_ip)=@_;
&function_begin($name);
&comment("");
&comment("Load the 2 words");
$trans="ebp";
&xor( $L, $L);
&xor( $R, $R);
# PIC-ification:-)
&picmeup("edx","DES_SPtrans");
#if ($cpp) { &picmeup("edx","DES_SPtrans"); }
#else { &lea("edx",&DWP("DES_SPtrans")); }
&push("edx"); # becomes &swtmp(1)
#
&mov($trans,&wparam(1)); # reloaded with DES_SPtrans in D_ENCRYPT
&push(&DWC(25)); # add a variable
&set_label("start");
for ($i=0; $i<16; $i+=2)
{
&comment("");
&comment("Round $i");
&D_ENCRYPT($i,$L,$R,$i*2,$trans,"eax","ebx","ecx","edx");
&comment("");
&comment("Round ".sprintf("%d",$i+1));
&D_ENCRYPT($i+1,$R,$L,($i+1)*2,$trans,"eax","ebx","ecx","edx");
}
&mov("ebx", &swtmp(0));
&mov("eax", $L);
&dec("ebx");
&mov($L, $R);
&mov($R, "eax");
&mov(&swtmp(0), "ebx");
&jnz(&label("start"));
&comment("");
&comment("FP");
&mov("edx",&wparam(0));
&FP_new($R,$L,"eax",3);
&mov(&DWP(0,"edx","",0),"eax");
&mov(&DWP(4,"edx","",0),$L);
&add("esp",8); # remove variables
&function_end($name);
}
sub D_ENCRYPT
{
local($r,$L,$R,$S,$trans,$u,$tmp1,$tmp2,$t)=@_;
&mov( $u, &wparam(2)); # 2
&mov( $t, $R);
&shr( $t, 16); # 1
&mov( $tmp2, &wparam(3)); # 2
&xor( $t, $R); # 1
&and( $u, $t); # 2
&and( $t, $tmp2); # 2
&mov( $tmp1, $u);
&shl( $tmp1, 16); # 1
&mov( $tmp2, $t);
&shl( $tmp2, 16); # 1
&xor( $u, $tmp1); # 2
&xor( $t, $tmp2); # 2
&mov( $tmp1, &DWP(&n2a($S*4),$trans,"",0)); # 2
&xor( $u, $tmp1);
&mov( $tmp2, &DWP(&n2a(($S+1)*4),$trans,"",0)); # 2
&xor( $u, $R);
&xor( $t, $R);
&xor( $t, $tmp2);
&and( $u, "0xfcfcfcfc" ); # 2
&xor( $tmp1, $tmp1); # 1
&and( $t, "0xcfcfcfcf" ); # 2
&xor( $tmp2, $tmp2);
&movb( &LB($tmp1), &LB($u) );
&movb( &LB($tmp2), &HB($u) );
&rotr( $t, 4 );
&mov( $trans, &swtmp(1));
&xor( $L, &DWP(" ",$trans,$tmp1,0));
&movb( &LB($tmp1), &LB($t) );
&xor( $L, &DWP("0x200",$trans,$tmp2,0));
&movb( &LB($tmp2), &HB($t) );
&shr( $u, 16);
&xor( $L, &DWP("0x100",$trans,$tmp1,0));
&movb( &LB($tmp1), &HB($u) );
&shr( $t, 16);
&xor( $L, &DWP("0x300",$trans,$tmp2,0));
&movb( &LB($tmp2), &HB($t) );
&and( $u, "0xff" );
&and( $t, "0xff" );
&mov( $tmp1, &DWP("0x600",$trans,$tmp1,0));
&xor( $L, $tmp1);
&mov( $tmp1, &DWP("0x700",$trans,$tmp2,0));
&xor( $L, $tmp1);
&mov( $tmp1, &DWP("0x400",$trans,$u,0));
&xor( $L, $tmp1);
&mov( $tmp1, &DWP("0x500",$trans,$t,0));
&xor( $L, $tmp1);
&mov( $trans, &wparam(1));
}
sub n2a
{
sprintf("%d",$_[0]);
}
# now has a side affect of rotating $a by $shift
sub R_PERM_OP
{
local($a,$b,$tt,$shift,$mask,$last)=@_;
&rotl( $a, $shift ) if ($shift != 0);
&mov( $tt, $a );
&xor( $a, $b );
&and( $a, $mask );
if ($notlast eq $b)
{
&xor( $b, $a );
&xor( $tt, $a );
}
else
{
&xor( $tt, $a );
&xor( $b, $a );
}
&comment("");
}
sub IP_new
{
local($l,$r,$tt,$lr)=@_;
&R_PERM_OP($l,$r,$tt, 4,"0xf0f0f0f0",$l);
&R_PERM_OP($r,$tt,$l,20,"0xfff0000f",$l);
&R_PERM_OP($l,$tt,$r,14,"0x33333333",$r);
&R_PERM_OP($tt,$r,$l,22,"0x03fc03fc",$r);
&R_PERM_OP($l,$r,$tt, 9,"0xaaaaaaaa",$r);
if ($lr != 3)
{
if (($lr-3) < 0)
{ &rotr($tt, 3-$lr); }
else { &rotl($tt, $lr-3); }
}
if ($lr != 2)
{
if (($lr-2) < 0)
{ &rotr($r, 2-$lr); }
else { &rotl($r, $lr-2); }
}
}
sub FP_new
{
local($l,$r,$tt,$lr)=@_;
if ($lr != 2)
{
if (($lr-2) < 0)
{ &rotl($r, 2-$lr); }
else { &rotr($r, $lr-2); }
}
if ($lr != 3)
{
if (($lr-3) < 0)
{ &rotl($l, 3-$lr); }
else { &rotr($l, $lr-3); }
}
&R_PERM_OP($l,$r,$tt, 0,"0xaaaaaaaa",$r);
&R_PERM_OP($tt,$r,$l,23,"0x03fc03fc",$r);
&R_PERM_OP($l,$r,$tt,10,"0x33333333",$l);
&R_PERM_OP($r,$tt,$l,18,"0xfff0000f",$l);
&R_PERM_OP($l,$tt,$r,12,"0xf0f0f0f0",$r);
&rotr($tt , 4);
}
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