3 # At some point it became apparent that the original SSLeay RC4
4 # assembler implementation performs suboptimaly on latest IA-32
5 # microarchitectures. After re-tuning performance has changed as
13 # (*) This number is actually a trade-off:-) It's possible to
14 # achieve +72%, but at the cost of -48% off PIII performance.
15 # In other words code performing further 13% faster on AMD
16 # would perform almost 2 times slower on Intel PIII...
17 # For reference! This code delivers ~80% of rc4-amd64.pl
18 # performance on the same Opteron machine.
19 # (**) This number requires compressed key schedule set up by
20 # RC4_set_key and therefore doesn't apply to 0.9.7 [option for
21 # compressed key schedule is implemented in 0.9.8 and later,
22 # see commentary section in rc4_skey.c for further details].
24 # <appro@fy.chalmers.se>
26 push(@INC,"perlasm","../../perlasm");
29 &asm_init($ARGV[0],"rc4-586.pl");
45 local($n,$p,$char)=@_;
55 &jbe(&label("finished"));
63 &jb(&label("finished"));
68 # &mov( $tx, &DWP(0,$d,$x,4)) if $p < 0;
70 &add( &LB($y), &LB($tx));
71 &inc( &LB($x)); # NEXT ROUND
72 &mov( $ty, &DWP(0,$d,$y,4));
74 &mov( &DWP(-4,$d,$x,4),$ty); # AGI
76 &mov( &DWP(0,$d,$y,4),$tx);
78 &mov( $tx, &DWP(0,$d,$x,4)) if $p < 1; # NEXT ROUND
79 &mov( $ty, &DWP(0,$d,$ty,4));
83 #moved up into last round
88 &movb( &BP($n,"esp","",0), &LB($ty));
92 # Note in+=8 has occured
93 &movb( &HB($ty), &BP(-1,$in,"",0));
95 &xorb(&LB($ty), &HB($ty));
97 &movb(&BP($n,$out,"",0),&LB($ty));
106 &function_begin_B($name,"");
108 &mov($ty,&wparam(1)); # len
110 &jne(&label("proceed"));
112 &set_label("proceed");
119 &xor( $x, $x); # avoid partial register stalls
121 &xor( $y, $y); # avoid partial register stalls
122 &mov( $d, &wparam(0)); # key
123 &mov( $in, &wparam(2));
125 &movb( &LB($x), &BP(0,$d,"",1));
126 &movb( &LB($y), &BP(4,$d,"",1));
128 &mov( $out, &wparam(3));
131 &stack_push(3); # 3 temp variables
134 # detect compressed schedule, see commentary section in rc4_skey.c...
135 # in 0.9.7 context ~50 bytes below RC4_CHAR label remain redundant,
136 # as compressed key schedule is set up in 0.9.8 and later.
137 &cmp(&DWP(256,$d),-1);
138 &je(&label("RC4_CHAR"));
140 &lea( $ty, &DWP(-8,$ty,$in));
142 # check for 0 length input
144 &mov( &swtmp(2), $ty); # this is now address to exit at
145 &mov( $tx, &DWP(0,$d,$x,4));
148 &jb( &label("end")); # less than 8 bytes
164 &comment("apply the cipher text");
165 # xor the cipher data with input
167 #&add( $out, 8); #moved up into last round
169 &mov( $tx, &swtmp(0));
170 &mov( $ty, &DWP(-8,$in,"",0));
172 &mov( $ty, &DWP(-4,$in,"",0));
173 &mov( &DWP(-8,$out,"",0), $tx);
174 &mov( $tx, &swtmp(1));
176 &mov( $ty, &swtmp(2)); # load end ptr;
177 &mov( &DWP(-4,$out,"",0), $tx);
178 &mov( $tx, &DWP(0,$d,$x,4));
180 &jbe(&label("start"));
184 # There is quite a bit of extra crap in RC4_loop() for this
194 &jmp(&label("finished"));
197 # this is essentially Intel P4 specific codepath, see rc4_skey.c,
198 # and is engaged in 0.9.8 and later context...
199 &set_label("RC4_CHAR");
201 &lea ($ty,&DWP(0,$in,$ty));
202 &mov (&swtmp(2),$ty);
204 # strangely enough unrolled loop performs over 20% slower...
205 &set_label("RC4_CHAR_loop");
206 &movz ($tx,&BP(0,$d,$x));
207 &add (&LB($y),&LB($tx));
208 &movz ($ty,&BP(0,$d,$y));
209 &movb (&BP(0,$d,$y),&LB($tx));
210 &movb (&BP(0,$d,$x),&LB($ty));
211 &add (&LB($ty),&LB($tx));
212 &movz ($ty,&BP(0,$d,$ty));
213 &xorb (&LB($ty),&BP(0,$in));
214 &movb (&BP(0,$out),&LB($ty));
218 &cmp ($in,&swtmp(2));
219 &jb (&label("RC4_CHAR_loop"));
221 &set_label("finished");
224 &movb( &BP(-4,$d,"",0),&LB($y));
225 &movb( &BP(-8,$d,"",0),&LB($x));
227 &function_end($name);