crypto/bn/asm/x86-mont.pl

   1 #! /usr/bin/env perl
   2 # Copyright 2005-2016 The OpenSSL Project Authors. All Rights Reserved.
   3 #
   4 # Licensed under the OpenSSL license (the "License").  You may not use
   5 # this file except in compliance with the License.  You can obtain a copy
   6 # in the file LICENSE in the source distribution or at
   7 # https://www.openssl.org/source/license.html
   8
   9
  10 # ====================================================================
  11 # Written by Andy Polyakov <appro@fy.chalmers.se> for the OpenSSL
  12 # project. The module is, however, dual licensed under OpenSSL and
  13 # CRYPTOGAMS licenses depending on where you obtain it. For further
  14 # details see http://www.openssl.org/~appro/cryptogams/.
  15 # ====================================================================
  16
  17 # October 2005
  18 #
  19 # This is a "teaser" code, as it can be improved in several ways...
  20 # First of all non-SSE2 path should be implemented (yes, for now it
  21 # performs Montgomery multiplication/convolution only on SSE2-capable
  22 # CPUs such as P4, others fall down to original code). Then inner loop
  23 # can be unrolled and modulo-scheduled to improve ILP and possibly
  24 # moved to 128-bit XMM register bank (though it would require input
  25 # rearrangement and/or increase bus bandwidth utilization). Dedicated
  26 # squaring procedure should give further performance improvement...
  27 # Yet, for being draft, the code improves rsa512 *sign* benchmark by
  28 # 110%(!), rsa1024 one - by 70% and rsa4096 - by 20%:-)
  29
  30 # December 2006
  31 #
  32 # Modulo-scheduling SSE2 loops results in further 15-20% improvement.
  33 # Integer-only code [being equipped with dedicated squaring procedure]
  34 # gives ~40% on rsa512 sign benchmark...
  35
  36 $0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1;
  37 push(@INC,"${dir}","${dir}../../perlasm");
  38 require "x86asm.pl";
  39
  40 $output = pop;
  41 open STDOUT,">$output";
  42
  43 &asm_init($ARGV[0],$0);
  44
  45 $sse2=0;
  46 for (@ARGV) { $sse2=1 if (/-DOPENSSL_IA32_SSE2/); }
  47
  48 &external_label("OPENSSL_ia32cap_P") if ($sse2);
  49
  50 &function_begin("bn_mul_mont");
  51
  52 $i="edx";
  53 $j="ecx";
  54 $ap="esi";      $tp="esi";              # overlapping variables!!!
  55 $rp="edi";      $bp="edi";              # overlapping variables!!!
  56 $np="ebp";
  57 $num="ebx";
  58
  59 $_num=&DWP(4*0,"esp");                  # stack top layout
  60 $_rp=&DWP(4*1,"esp");
  61 $_ap=&DWP(4*2,"esp");
  62 $_bp=&DWP(4*3,"esp");
  63 $_np=&DWP(4*4,"esp");
  64 $_n0=&DWP(4*5,"esp");   $_n0q=&QWP(4*5,"esp");
  65 $_sp=&DWP(4*6,"esp");
  66 $_bpend=&DWP(4*7,"esp");
  67 $frame=32;                              # size of above frame rounded up to 16n
  68
  69         &xor    ("eax","eax");
  70         &mov    ("edi",&wparam(5));     # int num
  71         &cmp    ("edi",4);
  72         &jl     (&label("just_leave"));
  73
  74         &lea    ("esi",&wparam(0));     # put aside pointer to argument block
  75         &lea    ("edx",&wparam(1));     # load ap
  76         &mov    ("ebp","esp");          # saved stack pointer!
  77         &add    ("edi",2);              # extra two words on top of tp
  78         &neg    ("edi");
  79         &lea    ("esp",&DWP(-$frame,"esp","edi",4));    # alloca($frame+4*(num+2))
  80         &neg    ("edi");
  81
  82         # minimize cache contention by arraning 2K window between stack
  83         # pointer and ap argument [np is also position sensitive vector,
  84         # but it's assumed to be near ap, as it's allocated at ~same
  85         # time].
  86         &mov    ("eax","esp");
  87         &sub    ("eax","edx");
  88         &and    ("eax",2047);
  89         &sub    ("esp","eax");          # this aligns sp and ap modulo 2048
  90
  91         &xor    ("edx","esp");
  92         &and    ("edx",2048);
  93         &xor    ("edx",2048);
  94         &sub    ("esp","edx");          # this splits them apart modulo 4096
  95
  96         &and    ("esp",-64);            # align to cache line
  97
  98         # An OS-agnostic version of __chkstk.
  99         #
 100         # Some OSes (Windows) insist on stack being "wired" to
 101         # physical memory in strictly sequential manner, i.e. if stack
 102         # allocation spans two pages, then reference to farmost one can
 103         # be punishable by SEGV. But page walking can do good even on
 104         # other OSes, because it guarantees that villain thread hits
 105         # the guard page before it can make damage to innocent one...
 106         &mov    ("eax","ebp");
 107         &sub    ("eax","esp");
 108         &and    ("eax",-4096);
 109 &set_label("page_walk");
 110         &mov    ("edx",&DWP(0,"esp","eax"));
 111         &sub    ("eax",4096);
 112         &data_byte(0x2e);
 113         &jnc    (&label("page_walk"));
 114
 115         ################################# load argument block...
 116         &mov    ("eax",&DWP(0*4,"esi"));# BN_ULONG *rp
 117         &mov    ("ebx",&DWP(1*4,"esi"));# const BN_ULONG *ap
 118         &mov    ("ecx",&DWP(2*4,"esi"));# const BN_ULONG *bp
 119         &mov    ("edx",&DWP(3*4,"esi"));# const BN_ULONG *np
 120         &mov    ("esi",&DWP(4*4,"esi"));# const BN_ULONG *n0
 121         #&mov   ("edi",&DWP(5*4,"esi"));# int num
 122
 123         &mov    ("esi",&DWP(0,"esi"));  # pull n0[0]
 124         &mov    ($_rp,"eax");           # ... save a copy of argument block
 125         &mov    ($_ap,"ebx");
 126         &mov    ($_bp,"ecx");
 127         &mov    ($_np,"edx");
 128         &mov    ($_n0,"esi");
 129         &lea    ($num,&DWP(-3,"edi"));  # num=num-1 to assist modulo-scheduling
 130         #&mov   ($_num,$num);           # redundant as $num is not reused
 131         &mov    ($_sp,"ebp");           # saved stack pointer!
 132 \f
 133 if($sse2) {
 134 $acc0="mm0";    # mmx register bank layout
 135 $acc1="mm1";
 136 $car0="mm2";
 137 $car1="mm3";
 138 $mul0="mm4";
 139 $mul1="mm5";
 140 $temp="mm6";
 141 $mask="mm7";
 142
 143         &picmeup("eax","OPENSSL_ia32cap_P");
 144         &bt     (&DWP(0,"eax"),26);
 145         &jnc    (&label("non_sse2"));
 146
 147         &mov    ("eax",-1);
 148         &movd   ($mask,"eax");          # mask 32 lower bits
 149
 150         &mov    ($ap,$_ap);             # load input pointers
 151         &mov    ($bp,$_bp);
 152         &mov    ($np,$_np);
 153
 154         &xor    ($i,$i);                # i=0
 155         &xor    ($j,$j);                # j=0
 156
 157         &movd   ($mul0,&DWP(0,$bp));            # bp[0]
 158         &movd   ($mul1,&DWP(0,$ap));            # ap[0]
 159         &movd   ($car1,&DWP(0,$np));            # np[0]
 160
 161         &pmuludq($mul1,$mul0);                  # ap[0]*bp[0]
 162         &movq   ($car0,$mul1);
 163         &movq   ($acc0,$mul1);                  # I wish movd worked for
 164         &pand   ($acc0,$mask);                  # inter-register transfers
 165
 166         &pmuludq($mul1,$_n0q);                  # *=n0
 167
 168         &pmuludq($car1,$mul1);                  # "t[0]"*np[0]*n0
 169         &paddq  ($car1,$acc0);
 170
 171         &movd   ($acc1,&DWP(4,$np));            # np[1]
 172         &movd   ($acc0,&DWP(4,$ap));            # ap[1]
 173
 174         &psrlq  ($car0,32);
 175         &psrlq  ($car1,32);
 176
 177         &inc    ($j);                           # j++
 178 &set_label("1st",16);
 179         &pmuludq($acc0,$mul0);                  # ap[j]*bp[0]
 180         &pmuludq($acc1,$mul1);                  # np[j]*m1
 181         &paddq  ($car0,$acc0);                  # +=c0
 182         &paddq  ($car1,$acc1);                  # +=c1
 183
 184         &movq   ($acc0,$car0);
 185         &pand   ($acc0,$mask);
 186         &movd   ($acc1,&DWP(4,$np,$j,4));       # np[j+1]
 187         &paddq  ($car1,$acc0);                  # +=ap[j]*bp[0];
 188         &movd   ($acc0,&DWP(4,$ap,$j,4));       # ap[j+1]
 189         &psrlq  ($car0,32);
 190         &movd   (&DWP($frame-4,"esp",$j,4),$car1);      # tp[j-1]=
 191         &psrlq  ($car1,32);
 192
 193         &lea    ($j,&DWP(1,$j));
 194         &cmp    ($j,$num);
 195         &jl     (&label("1st"));
 196
 197         &pmuludq($acc0,$mul0);                  # ap[num-1]*bp[0]
 198         &pmuludq($acc1,$mul1);                  # np[num-1]*m1
 199         &paddq  ($car0,$acc0);                  # +=c0
 200         &paddq  ($car1,$acc1);                  # +=c1
 201
 202         &movq   ($acc0,$car0);
 203         &pand   ($acc0,$mask);
 204         &paddq  ($car1,$acc0);                  # +=ap[num-1]*bp[0];
 205         &movd   (&DWP($frame-4,"esp",$j,4),$car1);      # tp[num-2]=
 206
 207         &psrlq  ($car0,32);
 208         &psrlq  ($car1,32);
 209
 210         &paddq  ($car1,$car0);
 211         &movq   (&QWP($frame,"esp",$num,4),$car1);      # tp[num].tp[num-1]
 212 \f
 213         &inc    ($i);                           # i++
 214 &set_label("outer");
 215         &xor    ($j,$j);                        # j=0
 216
 217         &movd   ($mul0,&DWP(0,$bp,$i,4));       # bp[i]
 218         &movd   ($mul1,&DWP(0,$ap));            # ap[0]
 219         &movd   ($temp,&DWP($frame,"esp"));     # tp[0]
 220         &movd   ($car1,&DWP(0,$np));            # np[0]
 221         &pmuludq($mul1,$mul0);                  # ap[0]*bp[i]
 222
 223         &paddq  ($mul1,$temp);                  # +=tp[0]
 224         &movq   ($acc0,$mul1);
 225         &movq   ($car0,$mul1);
 226         &pand   ($acc0,$mask);
 227
 228         &pmuludq($mul1,$_n0q);                  # *=n0
 229
 230         &pmuludq($car1,$mul1);
 231         &paddq  ($car1,$acc0);
 232
 233         &movd   ($temp,&DWP($frame+4,"esp"));   # tp[1]
 234         &movd   ($acc1,&DWP(4,$np));            # np[1]
 235         &movd   ($acc0,&DWP(4,$ap));            # ap[1]
 236
 237         &psrlq  ($car0,32);
 238         &psrlq  ($car1,32);
 239         &paddq  ($car0,$temp);                  # +=tp[1]
 240
 241         &inc    ($j);                           # j++
 242         &dec    ($num);
 243 &set_label("inner");
 244         &pmuludq($acc0,$mul0);                  # ap[j]*bp[i]
 245         &pmuludq($acc1,$mul1);                  # np[j]*m1
 246         &paddq  ($car0,$acc0);                  # +=c0
 247         &paddq  ($car1,$acc1);                  # +=c1
 248
 249         &movq   ($acc0,$car0);
 250         &movd   ($temp,&DWP($frame+4,"esp",$j,4));# tp[j+1]
 251         &pand   ($acc0,$mask);
 252         &movd   ($acc1,&DWP(4,$np,$j,4));       # np[j+1]
 253         &paddq  ($car1,$acc0);                  # +=ap[j]*bp[i]+tp[j]
 254         &movd   ($acc0,&DWP(4,$ap,$j,4));       # ap[j+1]
 255         &psrlq  ($car0,32);
 256         &movd   (&DWP($frame-4,"esp",$j,4),$car1);# tp[j-1]=
 257         &psrlq  ($car1,32);
 258         &paddq  ($car0,$temp);                  # +=tp[j+1]
 259
 260         &dec    ($num);
 261         &lea    ($j,&DWP(1,$j));                # j++
 262         &jnz    (&label("inner"));
 263
 264         &mov    ($num,$j);
 265         &pmuludq($acc0,$mul0);                  # ap[num-1]*bp[i]
 266         &pmuludq($acc1,$mul1);                  # np[num-1]*m1
 267         &paddq  ($car0,$acc0);                  # +=c0
 268         &paddq  ($car1,$acc1);                  # +=c1
 269
 270         &movq   ($acc0,$car0);
 271         &pand   ($acc0,$mask);
 272         &paddq  ($car1,$acc0);                  # +=ap[num-1]*bp[i]+tp[num-1]
 273         &movd   (&DWP($frame-4,"esp",$j,4),$car1);      # tp[num-2]=
 274         &psrlq  ($car0,32);
 275         &psrlq  ($car1,32);
 276
 277         &movd   ($temp,&DWP($frame+4,"esp",$num,4));    # += tp[num]
 278         &paddq  ($car1,$car0);
 279         &paddq  ($car1,$temp);
 280         &movq   (&QWP($frame,"esp",$num,4),$car1);      # tp[num].tp[num-1]
 281
 282         &lea    ($i,&DWP(1,$i));                # i++
 283         &cmp    ($i,$num);
 284         &jle    (&label("outer"));
 285
 286         &emms   ();                             # done with mmx bank
 287         &jmp    (&label("common_tail"));
 288
 289 &set_label("non_sse2",16);
 290 }
 291 \f
 292 if (0) {
 293         &mov    ("esp",$_sp);
 294         &xor    ("eax","eax");  # signal "not fast enough [yet]"
 295         &jmp    (&label("just_leave"));
 296         # While the below code provides competitive performance for
 297         # all key lengthes on modern Intel cores, it's still more
 298         # than 10% slower for 4096-bit key elsewhere:-( "Competitive"
 299         # means compared to the original integer-only assembler.
 300         # 512-bit RSA sign is better by ~40%, but that's about all
 301         # one can say about all CPUs...
 302 } else {
 303 $inp="esi";     # integer path uses these registers differently
 304 $word="edi";
 305 $carry="ebp";
 306
 307         &mov    ($inp,$_ap);
 308         &lea    ($carry,&DWP(1,$num));
 309         &mov    ($word,$_bp);
 310         &xor    ($j,$j);                                # j=0
 311         &mov    ("edx",$inp);
 312         &and    ($carry,1);                             # see if num is even
 313         &sub    ("edx",$word);                          # see if ap==bp
 314         &lea    ("eax",&DWP(4,$word,$num,4));           # &bp[num]
 315         &or     ($carry,"edx");
 316         &mov    ($word,&DWP(0,$word));                  # bp[0]
 317         &jz     (&label("bn_sqr_mont"));
 318         &mov    ($_bpend,"eax");
 319         &mov    ("eax",&DWP(0,$inp));
 320         &xor    ("edx","edx");
 321
 322 &set_label("mull",16);
 323         &mov    ($carry,"edx");
 324         &mul    ($word);                                # ap[j]*bp[0]
 325         &add    ($carry,"eax");
 326         &lea    ($j,&DWP(1,$j));
 327         &adc    ("edx",0);
 328         &mov    ("eax",&DWP(0,$inp,$j,4));              # ap[j+1]
 329         &cmp    ($j,$num);
 330         &mov    (&DWP($frame-4,"esp",$j,4),$carry);     # tp[j]=
 331         &jl     (&label("mull"));
 332
 333         &mov    ($carry,"edx");
 334         &mul    ($word);                                # ap[num-1]*bp[0]
 335          &mov   ($word,$_n0);
 336         &add    ("eax",$carry);
 337          &mov   ($inp,$_np);
 338         &adc    ("edx",0);
 339          &imul  ($word,&DWP($frame,"esp"));             # n0*tp[0]
 340
 341         &mov    (&DWP($frame,"esp",$num,4),"eax");      # tp[num-1]=
 342         &xor    ($j,$j);
 343         &mov    (&DWP($frame+4,"esp",$num,4),"edx");    # tp[num]=
 344         &mov    (&DWP($frame+8,"esp",$num,4),$j);       # tp[num+1]=
 345
 346         &mov    ("eax",&DWP(0,$inp));                   # np[0]
 347         &mul    ($word);                                # np[0]*m
 348         &add    ("eax",&DWP($frame,"esp"));             # +=tp[0]
 349         &mov    ("eax",&DWP(4,$inp));                   # np[1]
 350         &adc    ("edx",0);
 351         &inc    ($j);
 352
 353         &jmp    (&label("2ndmadd"));
 354 \f\f
 355 &set_label("1stmadd",16);
 356         &mov    ($carry,"edx");
 357         &mul    ($word);                                # ap[j]*bp[i]
 358         &add    ($carry,&DWP($frame,"esp",$j,4));       # +=tp[j]
 359         &lea    ($j,&DWP(1,$j));
 360         &adc    ("edx",0);
 361         &add    ($carry,"eax");
 362         &mov    ("eax",&DWP(0,$inp,$j,4));              # ap[j+1]
 363         &adc    ("edx",0);
 364         &cmp    ($j,$num);
 365         &mov    (&DWP($frame-4,"esp",$j,4),$carry);     # tp[j]=
 366         &jl     (&label("1stmadd"));
 367
 368         &mov    ($carry,"edx");
 369         &mul    ($word);                                # ap[num-1]*bp[i]
 370         &add    ("eax",&DWP($frame,"esp",$num,4));      # +=tp[num-1]
 371          &mov   ($word,$_n0);
 372         &adc    ("edx",0);
 373          &mov   ($inp,$_np);
 374         &add    ($carry,"eax");
 375         &adc    ("edx",0);
 376          &imul  ($word,&DWP($frame,"esp"));             # n0*tp[0]
 377
 378         &xor    ($j,$j);
 379         &add    ("edx",&DWP($frame+4,"esp",$num,4));    # carry+=tp[num]
 380         &mov    (&DWP($frame,"esp",$num,4),$carry);     # tp[num-1]=
 381         &adc    ($j,0);
 382          &mov   ("eax",&DWP(0,$inp));                   # np[0]
 383         &mov    (&DWP($frame+4,"esp",$num,4),"edx");    # tp[num]=
 384         &mov    (&DWP($frame+8,"esp",$num,4),$j);       # tp[num+1]=
 385
 386         &mul    ($word);                                # np[0]*m
 387         &add    ("eax",&DWP($frame,"esp"));             # +=tp[0]
 388         &mov    ("eax",&DWP(4,$inp));                   # np[1]
 389         &adc    ("edx",0);
 390         &mov    ($j,1);
 391 \f
 392 &set_label("2ndmadd",16);
 393         &mov    ($carry,"edx");
 394         &mul    ($word);                                # np[j]*m
 395         &add    ($carry,&DWP($frame,"esp",$j,4));       # +=tp[j]
 396         &lea    ($j,&DWP(1,$j));
 397         &adc    ("edx",0);
 398         &add    ($carry,"eax");
 399         &mov    ("eax",&DWP(0,$inp,$j,4));              # np[j+1]
 400         &adc    ("edx",0);
 401         &cmp    ($j,$num);
 402         &mov    (&DWP($frame-8,"esp",$j,4),$carry);     # tp[j-1]=
 403         &jl     (&label("2ndmadd"));
 404
 405         &mov    ($carry,"edx");
 406         &mul    ($word);                                # np[j]*m
 407         &add    ($carry,&DWP($frame,"esp",$num,4));     # +=tp[num-1]
 408         &adc    ("edx",0);
 409         &add    ($carry,"eax");
 410         &adc    ("edx",0);
 411         &mov    (&DWP($frame-4,"esp",$num,4),$carry);   # tp[num-2]=
 412
 413         &xor    ("eax","eax");
 414          &mov   ($j,$_bp);                              # &bp[i]
 415         &add    ("edx",&DWP($frame+4,"esp",$num,4));    # carry+=tp[num]
 416         &adc    ("eax",&DWP($frame+8,"esp",$num,4));    # +=tp[num+1]
 417          &lea   ($j,&DWP(4,$j));
 418         &mov    (&DWP($frame,"esp",$num,4),"edx");      # tp[num-1]=
 419          &cmp   ($j,$_bpend);
 420         &mov    (&DWP($frame+4,"esp",$num,4),"eax");    # tp[num]=
 421         &je     (&label("common_tail"));
 422
 423         &mov    ($word,&DWP(0,$j));                     # bp[i+1]
 424         &mov    ($inp,$_ap);
 425         &mov    ($_bp,$j);                              # &bp[++i]
 426         &xor    ($j,$j);
 427         &xor    ("edx","edx");
 428         &mov    ("eax",&DWP(0,$inp));
 429         &jmp    (&label("1stmadd"));
 430 \f
 431 &set_label("bn_sqr_mont",16);
 432 $sbit=$num;
 433         &mov    ($_num,$num);
 434         &mov    ($_bp,$j);                              # i=0
 435
 436         &mov    ("eax",$word);                          # ap[0]
 437         &mul    ($word);                                # ap[0]*ap[0]
 438         &mov    (&DWP($frame,"esp"),"eax");             # tp[0]=
 439         &mov    ($sbit,"edx");
 440         &shr    ("edx",1);
 441         &and    ($sbit,1);
 442         &inc    ($j);
 443 &set_label("sqr",16);
 444         &mov    ("eax",&DWP(0,$inp,$j,4));              # ap[j]
 445         &mov    ($carry,"edx");
 446         &mul    ($word);                                # ap[j]*ap[0]
 447         &add    ("eax",$carry);
 448         &lea    ($j,&DWP(1,$j));
 449         &adc    ("edx",0);
 450         &lea    ($carry,&DWP(0,$sbit,"eax",2));
 451         &shr    ("eax",31);
 452         &cmp    ($j,$_num);
 453         &mov    ($sbit,"eax");
 454         &mov    (&DWP($frame-4,"esp",$j,4),$carry);     # tp[j]=
 455         &jl     (&label("sqr"));
 456
 457         &mov    ("eax",&DWP(0,$inp,$j,4));              # ap[num-1]
 458         &mov    ($carry,"edx");
 459         &mul    ($word);                                # ap[num-1]*ap[0]
 460         &add    ("eax",$carry);
 461          &mov   ($word,$_n0);
 462         &adc    ("edx",0);
 463          &mov   ($inp,$_np);
 464         &lea    ($carry,&DWP(0,$sbit,"eax",2));
 465          &imul  ($word,&DWP($frame,"esp"));             # n0*tp[0]
 466         &shr    ("eax",31);
 467         &mov    (&DWP($frame,"esp",$j,4),$carry);       # tp[num-1]=
 468
 469         &lea    ($carry,&DWP(0,"eax","edx",2));
 470          &mov   ("eax",&DWP(0,$inp));                   # np[0]
 471         &shr    ("edx",31);
 472         &mov    (&DWP($frame+4,"esp",$j,4),$carry);     # tp[num]=
 473         &mov    (&DWP($frame+8,"esp",$j,4),"edx");      # tp[num+1]=
 474
 475         &mul    ($word);                                # np[0]*m
 476         &add    ("eax",&DWP($frame,"esp"));             # +=tp[0]
 477         &mov    ($num,$j);
 478         &adc    ("edx",0);
 479         &mov    ("eax",&DWP(4,$inp));                   # np[1]
 480         &mov    ($j,1);
 481 \f\f
 482 &set_label("3rdmadd",16);
 483         &mov    ($carry,"edx");
 484         &mul    ($word);                                # np[j]*m
 485         &add    ($carry,&DWP($frame,"esp",$j,4));       # +=tp[j]
 486         &adc    ("edx",0);
 487         &add    ($carry,"eax");
 488         &mov    ("eax",&DWP(4,$inp,$j,4));              # np[j+1]
 489         &adc    ("edx",0);
 490         &mov    (&DWP($frame-4,"esp",$j,4),$carry);     # tp[j-1]=
 491
 492         &mov    ($carry,"edx");
 493         &mul    ($word);                                # np[j+1]*m
 494         &add    ($carry,&DWP($frame+4,"esp",$j,4));     # +=tp[j+1]
 495         &lea    ($j,&DWP(2,$j));
 496         &adc    ("edx",0);
 497         &add    ($carry,"eax");
 498         &mov    ("eax",&DWP(0,$inp,$j,4));              # np[j+2]
 499         &adc    ("edx",0);
 500         &cmp    ($j,$num);
 501         &mov    (&DWP($frame-8,"esp",$j,4),$carry);     # tp[j]=
 502         &jl     (&label("3rdmadd"));
 503
 504         &mov    ($carry,"edx");
 505         &mul    ($word);                                # np[j]*m
 506         &add    ($carry,&DWP($frame,"esp",$num,4));     # +=tp[num-1]
 507         &adc    ("edx",0);
 508         &add    ($carry,"eax");
 509         &adc    ("edx",0);
 510         &mov    (&DWP($frame-4,"esp",$num,4),$carry);   # tp[num-2]=
 511
 512         &mov    ($j,$_bp);                              # i
 513         &xor    ("eax","eax");
 514         &mov    ($inp,$_ap);
 515         &add    ("edx",&DWP($frame+4,"esp",$num,4));    # carry+=tp[num]
 516         &adc    ("eax",&DWP($frame+8,"esp",$num,4));    # +=tp[num+1]
 517         &mov    (&DWP($frame,"esp",$num,4),"edx");      # tp[num-1]=
 518         &cmp    ($j,$num);
 519         &mov    (&DWP($frame+4,"esp",$num,4),"eax");    # tp[num]=
 520         &je     (&label("common_tail"));
 521 \f
 522         &mov    ($word,&DWP(4,$inp,$j,4));              # ap[i]
 523         &lea    ($j,&DWP(1,$j));
 524         &mov    ("eax",$word);
 525         &mov    ($_bp,$j);                              # ++i
 526         &mul    ($word);                                # ap[i]*ap[i]
 527         &add    ("eax",&DWP($frame,"esp",$j,4));        # +=tp[i]
 528         &adc    ("edx",0);
 529         &mov    (&DWP($frame,"esp",$j,4),"eax");        # tp[i]=
 530         &xor    ($carry,$carry);
 531         &cmp    ($j,$num);
 532         &lea    ($j,&DWP(1,$j));
 533         &je     (&label("sqrlast"));
 534
 535         &mov    ($sbit,"edx");                          # zaps $num
 536         &shr    ("edx",1);
 537         &and    ($sbit,1);
 538 &set_label("sqradd",16);
 539         &mov    ("eax",&DWP(0,$inp,$j,4));              # ap[j]
 540         &mov    ($carry,"edx");
 541         &mul    ($word);                                # ap[j]*ap[i]
 542         &add    ("eax",$carry);
 543         &lea    ($carry,&DWP(0,"eax","eax"));
 544         &adc    ("edx",0);
 545         &shr    ("eax",31);
 546         &add    ($carry,&DWP($frame,"esp",$j,4));       # +=tp[j]
 547         &lea    ($j,&DWP(1,$j));
 548         &adc    ("eax",0);
 549         &add    ($carry,$sbit);
 550         &adc    ("eax",0);
 551         &cmp    ($j,$_num);
 552         &mov    (&DWP($frame-4,"esp",$j,4),$carry);     # tp[j]=
 553         &mov    ($sbit,"eax");
 554         &jle    (&label("sqradd"));
 555
 556         &mov    ($carry,"edx");
 557         &add    ("edx","edx");
 558         &shr    ($carry,31);
 559         &add    ("edx",$sbit);
 560         &adc    ($carry,0);
 561 &set_label("sqrlast");
 562         &mov    ($word,$_n0);
 563         &mov    ($inp,$_np);
 564         &imul   ($word,&DWP($frame,"esp"));             # n0*tp[0]
 565
 566         &add    ("edx",&DWP($frame,"esp",$j,4));        # +=tp[num]
 567         &mov    ("eax",&DWP(0,$inp));                   # np[0]
 568         &adc    ($carry,0);
 569         &mov    (&DWP($frame,"esp",$j,4),"edx");        # tp[num]=
 570         &mov    (&DWP($frame+4,"esp",$j,4),$carry);     # tp[num+1]=
 571
 572         &mul    ($word);                                # np[0]*m
 573         &add    ("eax",&DWP($frame,"esp"));             # +=tp[0]
 574         &lea    ($num,&DWP(-1,$j));
 575         &adc    ("edx",0);
 576         &mov    ($j,1);
 577         &mov    ("eax",&DWP(4,$inp));                   # np[1]
 578
 579         &jmp    (&label("3rdmadd"));
 580 }
 581 \f
 582 &set_label("common_tail",16);
 583         &mov    ($np,$_np);                     # load modulus pointer
 584         &mov    ($rp,$_rp);                     # load result pointer
 585         &lea    ($tp,&DWP($frame,"esp"));       # [$ap and $bp are zapped]
 586
 587         &mov    ("eax",&DWP(0,$tp));            # tp[0]
 588         &mov    ($j,$num);                      # j=num-1
 589         &xor    ($i,$i);                        # i=0 and clear CF!
 590
 591 &set_label("sub",16);
 592         &sbb    ("eax",&DWP(0,$np,$i,4));
 593         &mov    (&DWP(0,$rp,$i,4),"eax");       # rp[i]=tp[i]-np[i]
 594         &dec    ($j);                           # doesn't affect CF!
 595         &mov    ("eax",&DWP(4,$tp,$i,4));       # tp[i+1]
 596         &lea    ($i,&DWP(1,$i));                # i++
 597         &jge    (&label("sub"));
 598
 599         &sbb    ("eax",0);                      # handle upmost overflow bit
 600         &and    ($tp,"eax");
 601         &not    ("eax");
 602         &mov    ($np,$rp);
 603         &and    ($np,"eax");
 604         &or     ($tp,$np);                      # tp=carry?tp:rp
 605
 606 &set_label("copy",16);                          # copy or in-place refresh
 607         &mov    ("eax",&DWP(0,$tp,$num,4));
 608         &mov    (&DWP(0,$rp,$num,4),"eax");     # rp[i]=tp[i]
 609         &mov    (&DWP($frame,"esp",$num,4),$j); # zap temporary vector
 610         &dec    ($num);
 611         &jge    (&label("copy"));
 612
 613         &mov    ("esp",$_sp);           # pull saved stack pointer
 614         &mov    ("eax",1);
 615 &set_label("just_leave");
 616 &function_end("bn_mul_mont");
 617
 618 &asciz("Montgomery Multiplication for x86, CRYPTOGAMS by <appro\@openssl.org>");
 619
 620 &asm_finish();
 621
 622 close STDOUT;