1 #!/usr/bin/env perl 2 3 # ==================================================================== 4 # [Re]written by Andy Polyakov <appro (at] fy.chalmers.se> for the OpenSSL 5 # project. The module is, however, dual licensed under OpenSSL and 6 # CRYPTOGAMS licenses depending on where you obtain it. For further 7 # details see http://www.openssl.org/~appro/cryptogams/. 8 # ==================================================================== 9 10 # At some point it became apparent that the original SSLeay RC4 11 # assembler implementation performs suboptimally on latest IA-32 12 # microarchitectures. After re-tuning performance has changed as 13 # following: 14 # 15 # Pentium -10% 16 # Pentium III +12% 17 # AMD +50%(*) 18 # P4 +250%(**) 19 # 20 # (*) This number is actually a trade-off:-) It's possible to 21 # achieve +72%, but at the cost of -48% off PIII performance. 22 # In other words code performing further 13% faster on AMD 23 # would perform almost 2 times slower on Intel PIII... 24 # For reference! This code delivers ~80% of rc4-amd64.pl 25 # performance on the same Opteron machine. 26 # (**) This number requires compressed key schedule set up by 27 # RC4_set_key [see commentary below for further details]. 28 # 29 # <appro (at] fy.chalmers.se> 30 31 $0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1; 32 push(@INC,"${dir}","${dir}../../perlasm"); 33 require "x86asm.pl"; 34 35 &asm_init($ARGV[0],"rc4-586.pl"); 36 37 $xx="eax"; 38 $yy="ebx"; 39 $tx="ecx"; 40 $ty="edx"; 41 $inp="esi"; 42 $out="ebp"; 43 $dat="edi"; 44 45 sub RC4_loop { 46 my $i=shift; 47 my $func = ($i==0)?*mov:*or; 48 49 &add (&LB($yy),&LB($tx)); 50 &mov ($ty,&DWP(0,$dat,$yy,4)); 51 &mov (&DWP(0,$dat,$yy,4),$tx); 52 &mov (&DWP(0,$dat,$xx,4),$ty); 53 &add ($ty,$tx); 54 &inc (&LB($xx)); 55 &and ($ty,0xff); 56 &ror ($out,8) if ($i!=0); 57 if ($i<3) { 58 &mov ($tx,&DWP(0,$dat,$xx,4)); 59 } else { 60 &mov ($tx,&wparam(3)); # reload [re-biased] out 61 } 62 &$func ($out,&DWP(0,$dat,$ty,4)); 63 } 64 65 # void RC4(RC4_KEY *key,size_t len,const unsigned char *inp,unsigned char *out); 66 &function_begin("RC4"); 67 &mov ($dat,&wparam(0)); # load key schedule pointer 68 &mov ($ty, &wparam(1)); # load len 69 &mov ($inp,&wparam(2)); # load inp 70 &mov ($out,&wparam(3)); # load out 71 72 &xor ($xx,$xx); # avoid partial register stalls 73 &xor ($yy,$yy); 74 75 &cmp ($ty,0); # safety net 76 &je (&label("abort")); 77 78 &mov (&LB($xx),&BP(0,$dat)); # load key->x 79 &mov (&LB($yy),&BP(4,$dat)); # load key->y 80 &add ($dat,8); 81 82 &lea ($tx,&DWP(0,$inp,$ty)); 83 &sub ($out,$inp); # re-bias out 84 &mov (&wparam(1),$tx); # save input+len 85 86 &inc (&LB($xx)); 87 88 # detect compressed key schedule... 89 &cmp (&DWP(256,$dat),-1); 90 &je (&label("RC4_CHAR")); 91 92 &mov ($tx,&DWP(0,$dat,$xx,4)); 93 94 &and ($ty,-4); # how many 4-byte chunks? 95 &jz (&label("loop1")); 96 97 &lea ($ty,&DWP(-4,$inp,$ty)); 98 &mov (&wparam(2),$ty); # save input+(len/4)*4-4 99 &mov (&wparam(3),$out); # $out as accumulator in this loop 100 101 &set_label("loop4",16); 102 for ($i=0;$i<4;$i++) { RC4_loop($i); } 103 &ror ($out,8); 104 &xor ($out,&DWP(0,$inp)); 105 &cmp ($inp,&wparam(2)); # compare to input+(len/4)*4-4 106 &mov (&DWP(0,$tx,$inp),$out);# $tx holds re-biased out here 107 &lea ($inp,&DWP(4,$inp)); 108 &mov ($tx,&DWP(0,$dat,$xx,4)); 109 &jb (&label("loop4")); 110 111 &cmp ($inp,&wparam(1)); # compare to input+len 112 &je (&label("done")); 113 &mov ($out,&wparam(3)); # restore $out 114 115 &set_label("loop1",16); 116 &add (&LB($yy),&LB($tx)); 117 &mov ($ty,&DWP(0,$dat,$yy,4)); 118 &mov (&DWP(0,$dat,$yy,4),$tx); 119 &mov (&DWP(0,$dat,$xx,4),$ty); 120 &add ($ty,$tx); 121 &inc (&LB($xx)); 122 &and ($ty,0xff); 123 &mov ($ty,&DWP(0,$dat,$ty,4)); 124 &xor (&LB($ty),&BP(0,$inp)); 125 &lea ($inp,&DWP(1,$inp)); 126 &mov ($tx,&DWP(0,$dat,$xx,4)); 127 &cmp ($inp,&wparam(1)); # compare to input+len 128 &mov (&BP(-1,$out,$inp),&LB($ty)); 129 &jb (&label("loop1")); 130 131 &jmp (&label("done")); 132 133 # this is essentially Intel P4 specific codepath... 134 &set_label("RC4_CHAR",16); 135 &movz ($tx,&BP(0,$dat,$xx)); 136 # strangely enough unrolled loop performs over 20% slower... 137 &set_label("cloop1"); 138 &add (&LB($yy),&LB($tx)); 139 &movz ($ty,&BP(0,$dat,$yy)); 140 &mov (&BP(0,$dat,$yy),&LB($tx)); 141 &mov (&BP(0,$dat,$xx),&LB($ty)); 142 &add (&LB($ty),&LB($tx)); 143 &movz ($ty,&BP(0,$dat,$ty)); 144 &add (&LB($xx),1); 145 &xor (&LB($ty),&BP(0,$inp)); 146 &lea ($inp,&DWP(1,$inp)); 147 &movz ($tx,&BP(0,$dat,$xx)); 148 &cmp ($inp,&wparam(1)); 149 &mov (&BP(-1,$out,$inp),&LB($ty)); 150 &jb (&label("cloop1")); 151 152 &set_label("done"); 153 &dec (&LB($xx)); 154 &mov (&BP(-4,$dat),&LB($yy)); # save key->y 155 &mov (&BP(-8,$dat),&LB($xx)); # save key->x 156 &set_label("abort"); 157 &function_end("RC4"); 158 159 ######################################################################## 160 161 $inp="esi"; 162 $out="edi"; 163 $idi="ebp"; 164 $ido="ecx"; 165 $idx="edx"; 166 167 &external_label("OPENSSL_ia32cap_P"); 168 169 # void RC4_set_key(RC4_KEY *key,int len,const unsigned char *data); 170 &function_begin("RC4_set_key"); 171 &mov ($out,&wparam(0)); # load key 172 &mov ($idi,&wparam(1)); # load len 173 &mov ($inp,&wparam(2)); # load data 174 &picmeup($idx,"OPENSSL_ia32cap_P"); 175 176 &lea ($out,&DWP(2*4,$out)); # &key->data 177 &lea ($inp,&DWP(0,$inp,$idi)); # $inp to point at the end 178 &neg ($idi); 179 &xor ("eax","eax"); 180 &mov (&DWP(-4,$out),$idi); # borrow key->y 181 182 &bt (&DWP(0,$idx),20); # check for bit#20 183 &jc (&label("c1stloop")); 184 185 &set_label("w1stloop",16); 186 &mov (&DWP(0,$out,"eax",4),"eax"); # key->data[i]=i; 187 &add (&LB("eax"),1); # i++; 188 &jnc (&label("w1stloop")); 189 190 &xor ($ido,$ido); 191 &xor ($idx,$idx); 192 193 &set_label("w2ndloop",16); 194 &mov ("eax",&DWP(0,$out,$ido,4)); 195 &add (&LB($idx),&BP(0,$inp,$idi)); 196 &add (&LB($idx),&LB("eax")); 197 &add ($idi,1); 198 &mov ("ebx",&DWP(0,$out,$idx,4)); 199 &jnz (&label("wnowrap")); 200 &mov ($idi,&DWP(-4,$out)); 201 &set_label("wnowrap"); 202 &mov (&DWP(0,$out,$idx,4),"eax"); 203 &mov (&DWP(0,$out,$ido,4),"ebx"); 204 &add (&LB($ido),1); 205 &jnc (&label("w2ndloop")); 206 &jmp (&label("exit")); 207 208 # Unlike all other x86 [and x86_64] implementations, Intel P4 core 209 # [including EM64T] was found to perform poorly with above "32-bit" key 210 # schedule, a.k.a. RC4_INT. Performance improvement for IA-32 hand-coded 211 # assembler turned out to be 3.5x if re-coded for compressed 8-bit one, 212 # a.k.a. RC4_CHAR! It's however inappropriate to just switch to 8-bit 213 # schedule for x86[_64], because non-P4 implementations suffer from 214 # significant performance losses then, e.g. PIII exhibits >2x 215 # deterioration, and so does Opteron. In order to assure optimal 216 # all-round performance, we detect P4 at run-time and set up compressed 217 # key schedule, which is recognized by RC4 procedure. 218 219 &set_label("c1stloop",16); 220 &mov (&BP(0,$out,"eax"),&LB("eax")); # key->data[i]=i; 221 &add (&LB("eax"),1); # i++; 222 &jnc (&label("c1stloop")); 223 224 &xor ($ido,$ido); 225 &xor ($idx,$idx); 226 &xor ("ebx","ebx"); 227 228 &set_label("c2ndloop",16); 229 &mov (&LB("eax"),&BP(0,$out,$ido)); 230 &add (&LB($idx),&BP(0,$inp,$idi)); 231 &add (&LB($idx),&LB("eax")); 232 &add ($idi,1); 233 &mov (&LB("ebx"),&BP(0,$out,$idx)); 234 &jnz (&label("cnowrap")); 235 &mov ($idi,&DWP(-4,$out)); 236 &set_label("cnowrap"); 237 &mov (&BP(0,$out,$idx),&LB("eax")); 238 &mov (&BP(0,$out,$ido),&LB("ebx")); 239 &add (&LB($ido),1); 240 &jnc (&label("c2ndloop")); 241 242 &mov (&DWP(256,$out),-1); # mark schedule as compressed 243 244 &set_label("exit"); 245 &xor ("eax","eax"); 246 &mov (&DWP(-8,$out),"eax"); # key->x=0; 247 &mov (&DWP(-4,$out),"eax"); # key->y=0; 248 &function_end("RC4_set_key"); 249 250 # const char *RC4_options(void); 251 &function_begin_B("RC4_options"); 252 &call (&label("pic_point")); 253 &set_label("pic_point"); 254 &blindpop("eax"); 255 &lea ("eax",&DWP(&label("opts")."-".&label("pic_point"),"eax")); 256 &picmeup("edx","OPENSSL_ia32cap_P"); 257 &bt (&DWP(0,"edx"),20); 258 &jnc (&label("skip")); 259 &add ("eax",12); 260 &set_label("skip"); 261 &ret (); 262 &set_label("opts",64); 263 &asciz ("rc4(4x,int)"); 264 &asciz ("rc4(1x,char)"); 265 &asciz ("RC4 for x86, CRYPTOGAMS by <appro\@openssl.org>"); 266 &align (64); 267 &function_end_B("RC4_options"); 268 269 &asm_finish(); 270 271
