
#!/usr/local/bin/perl

$prog="bf586.pl";

# base code is in microsft
# op dest, source
# format.
#

if (    ($ARGV[0] eq "elf"))
        { require "x86unix.pl"; }
elsif ( ($ARGV[0] eq "a.out"))
        { $aout=1; require "x86unix.pl"; }
elsif ( ($ARGV[0] eq "sol"))
        { $sol=1; require "x86unix.pl"; }
elsif ( ($ARGV[0] eq "cpp"))
        { $cpp=1; require "x86unix.pl"; }
elsif ( ($ARGV[0] eq "win32"))
        { require "x86ms.pl"; }
else
        {
        print STDERR <<"EOF";
Pick one target type from
        elf     - linux, FreeBSD etc
        a.out   - old linux
        sol     - x86 solaris
        cpp     - format so x86unix.cpp can be used
        win32   - Windows 95/Windows NT
EOF
        exit(1);
        }

&comment("Don't even think of reading this code");
&comment("It was automatically generated by $prog");
&comment("Which is a perl program used to generate the x86 assember for");
&comment("any of elf, a.out, Win32, or Solaris");
&comment("It can be found in SSLeay 0.7.0+");
&comment("eric <eay\@mincom.oz.au>");
&comment("");

&file("bfx86xxxx");

$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");

&file_end();

sub des_encrypt
        {
        local($name)=@_;

        &function_begin($name,3);

        &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

        &mov("ebp",&wparam(2)); # get encrypt flag
        &cmp("ebp","0");
        &je(&label("start_decrypt"));

        &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);

        &set_label("start_decrypt");

        &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]);
        }
