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|
#!/usr/local/bin/perl
# define for pentium pro friendly version
push(@INC,"perlasm","../../perlasm");
require "x86asm.pl";
&asm_init($ARGV[0],"rc4-586.pl");
$tx="eax";
$ty="ebx";
$x="ecx";
$y="edx";
$in="esi";
$out="edi";
$d="ebp";
&RC4("RC4");
&asm_finish();
sub RC4_loop
{
local($n,$p,$char)=@_;
&comment("Round $n");
if ($char)
{
if ($p >= 0)
{
&mov($ty, &swtmp(2));
&cmp($ty, $in);
&jle(&label("finished"));
&inc($in);
}
else
{
&add($ty, 8);
&inc($in);
&cmp($ty, $in);
&jl(&label("finished"));
&mov(&swtmp(2), $ty);
}
}
# Moved out
# &mov( $tx, &DWP(0,$d,$x,4)) if $p < 0;
&add( $y, $tx);
&and( $y, 0xff);
&inc( $x); # NEXT ROUND
&mov( $ty, &DWP(0,$d,$y,4));
# XXX
&mov( &DWP(-4,$d,$x,4),$ty); # AGI
&add( $ty, $tx);
&and( $x, 0xff); # NEXT ROUND
&and( $ty, 0xff);
&mov( &DWP(0,$d,$y,4),$tx);
&nop();
&mov( $ty, &DWP(0,$d,$ty,4));
&mov( $tx, &DWP(0,$d,$x,4)) if $p < 1; # NEXT ROUND
# XXX
if (!$char)
{
#moved up into last round
if ($p >= 1)
{
&add( $out, 8)
}
&movb( &BP($n,"esp","",0), &LB($ty));
}
else
{
# Note in+=8 has occured
&movb( &HB($ty), &BP(-1,$in,"",0));
# XXX
&xorb(&LB($ty), &HB($ty));
# XXX
&movb(&BP($n,$out,"",0),&LB($ty));
}
}
sub RC4
{
local($name)=@_;
&function_begin_B($name,"");
&comment("");
&push("ebp");
&push("ebx");
&mov( $d, &wparam(0)); # key
&mov( $ty, &wparam(1)); # num
&push("esi");
&push("edi");
&mov( $x, &DWP(0,$d,"",1));
&mov( $y, &DWP(4,$d,"",1));
&mov( $in, &wparam(2));
&inc( $x);
&stack_push(3); # 3 temp variables
&add( $d, 8);
&and( $x, 0xff);
&lea( $ty, &DWP(-8,$ty,$in));
# check for 0 length input
&mov( $out, &wparam(3));
&mov( &swtmp(2), $ty); # this is now address to exit at
&mov( $tx, &DWP(0,$d,$x,4));
&cmp( $ty, $in);
&jl( &label("end")); # less than 8 bytes
&set_label("start");
# filling DELAY SLOT
&add( $in, 8);
&RC4_loop(0,-1,0);
&RC4_loop(1,0,0);
&RC4_loop(2,0,0);
&RC4_loop(3,0,0);
&RC4_loop(4,0,0);
&RC4_loop(5,0,0);
&RC4_loop(6,0,0);
&RC4_loop(7,1,0);
&comment("apply the cipher text");
# xor the cipher data with input
#&add( $out, 8); #moved up into last round
&mov( $tx, &swtmp(0));
&mov( $ty, &DWP(-8,$in,"",0));
&xor( $tx, $ty);
&mov( $ty, &DWP(-4,$in,"",0));
&mov( &DWP(-8,$out,"",0), $tx);
&mov( $tx, &swtmp(1));
&xor( $tx, $ty);
&mov( $ty, &swtmp(2)); # load end ptr;
&mov( &DWP(-4,$out,"",0), $tx);
&mov( $tx, &DWP(0,$d,$x,4));
&cmp($in, $ty);
&jle(&label("start"));
&set_label("end");
# There is quite a bit of extra crap in RC4_loop() for this
# first round
&RC4_loop(0,-1,1);
&RC4_loop(1,0,1);
&RC4_loop(2,0,1);
&RC4_loop(3,0,1);
&RC4_loop(4,0,1);
&RC4_loop(5,0,1);
&RC4_loop(6,1,1);
&set_label("finished");
&dec( $x);
&stack_pop(3);
&mov( &DWP(-4,$d,"",0),$y);
&movb( &BP(-8,$d,"",0),&LB($x));
&function_end($name);
}
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