&asm_init($ARGV[0],"rc4-586.pl");
-$tx="eax";
-$ty="ebx";
-$x="ecx";
-$y="edx";
+$x="eax";
+$y="ebx";
+$tx="ecx";
+$ty="edx";
$in="esi";
$out="edi";
$d="ebp";
{
&mov($ty, &swtmp(2));
&cmp($ty, $in);
- &jle(&label("finished"));
+ &jbe(&label("finished"));
&inc($in);
}
else
&add($ty, 8);
&inc($in);
&cmp($ty, $in);
- &jl(&label("finished"));
+ &jb(&label("finished"));
&mov(&swtmp(2), $ty);
}
}
&function_begin_B($name,"");
+ &mov($ty,&wparam(1)); # len
+ &cmp($ty,0);
+ &jne(&label("proceed"));
+ &ret();
+ &set_label("proceed");
+
&comment("");
&push("ebp");
&push("ebx");
- &mov( $d, &wparam(0)); # key
- &mov( $ty, &wparam(1)); # num
&push("esi");
&push("edi");
+ &mov( $d, &wparam(0)); # key
+ &mov( $in, &wparam(2));
&mov( $x, &DWP(0,$d,"",1));
&mov( $y, &DWP(4,$d,"",1));
- &mov( $in, &wparam(2));
+ &mov( $out, &wparam(3));
&inc( $x);
&stack_push(3); # 3 temp variables
&add( $d, 8);
&and( $x, 0xff);
+ # detect compressed schedule, see commentary section in rc4_skey.c...
+ &cmp(&DWP(256,$d),-1);
+ &je(&label("RC4_CHAR"));
+
&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, $in);
- &jl( &label("end")); # less than 8 bytes
+ &jb( &label("end")); # less than 8 bytes
&set_label("start");
&mov( &DWP(-4,$out,"",0), $tx);
&mov( $tx, &DWP(0,$d,$x,4));
&cmp($in, $ty);
- &jle(&label("start"));
+ &jbe(&label("start"));
&set_label("end");
&RC4_loop(5,0,1);
&RC4_loop(6,1,1);
+ &jmp(&label("finished"));
+
+ &align(16);
+ # this is essentially Intel P4 specific codepath, see rc4_skey.c...
+ &set_label("RC4_CHAR");
+
+ &lea ($ty,&DWP(0,$in,$ty));
+ &mov (&swtmp(2),$ty);
+
+ # strangely enough unrolled loop performs over 20% slower...
+ &set_label("RC4_CHAR_loop");
+ &movz ($tx,&BP(0,$d,$x));
+ &add (&LB($y),&LB($tx));
+ &movz ($ty,&BP(0,$d,$y));
+ &movb (&BP(0,$d,$y),&LB($tx));
+ &movb (&BP(0,$d,$x),&LB($ty));
+ &add (&LB($ty),&LB($tx));
+ &movz ($ty,&BP(0,$d,$ty));
+ &xorb (&LB($ty),&BP(0,$in));
+ &movb (&BP(0,$out),&LB($ty));
+ &inc (&LB($x));
+ &inc ($in);
+ &inc ($out);
+ &cmp ($in,&swtmp(2));
+ &jb (&label("RC4_CHAR_loop"));
+
&set_label("finished");
&dec( $x);
&stack_pop(3);