crypto/bn/asm/ia64.S

   1 .explicit
   2 .text
   3 .ident  "ia64.S, Version 2.1"
   4 .ident  "IA-64 ISA artwork by Andy Polyakov <appro@fy.chalmers.se>"
   5
   6 // Copyright 2001-2016 The OpenSSL Project Authors. All Rights Reserved.
   7 //
   8 // Licensed under the OpenSSL license (the "License").  You may not use
   9 // this file except in compliance with the License.  You can obtain a copy
  10 // in the file LICENSE in the source distribution or at
  11 // https://www.openssl.org/source/license.html
  12
  13 //
  14 // ====================================================================
  15 // Written by Andy Polyakov <appro@fy.chalmers.se> for the OpenSSL
  16 // project.
  17 //
  18 // Rights for redistribution and usage in source and binary forms are
  19 // granted according to the OpenSSL license. Warranty of any kind is
  20 // disclaimed.
  21 // ====================================================================
  22 //
  23 // Version 2.x is Itanium2 re-tune. Few words about how Itanum2 is
  24 // different from Itanium to this module viewpoint. Most notably, is it
  25 // "wider" than Itanium? Can you experience loop scalability as
  26 // discussed in commentary sections? Not really:-( Itanium2 has 6
  27 // integer ALU ports, i.e. it's 2 ports wider, but it's not enough to
  28 // spin twice as fast, as I need 8 IALU ports. Amount of floating point
  29 // ports is the same, i.e. 2, while I need 4. In other words, to this
  30 // module Itanium2 remains effectively as "wide" as Itanium. Yet it's
  31 // essentially different in respect to this module, and a re-tune was
  32 // required. Well, because some instruction latencies has changed. Most
  33 // noticeably those intensively used:
  34 //
  35 //                      Itanium Itanium2
  36 //      ldf8            9       6               L2 hit
  37 //      ld8             2       1               L1 hit
  38 //      getf            2       5
  39 //      xma[->getf]     7[+1]   4[+0]
  40 //      add[->st8]      1[+1]   1[+0]
  41 //
  42 // What does it mean? You might ratiocinate that the original code
  43 // should run just faster... Because sum of latencies is smaller...
  44 // Wrong! Note that getf latency increased. This means that if a loop is
  45 // scheduled for lower latency (as they were), then it will suffer from
  46 // stall condition and the code will therefore turn anti-scalable, e.g.
  47 // original bn_mul_words spun at 5*n or 2.5 times slower than expected
  48 // on Itanium2! What to do? Reschedule loops for Itanium2? But then
  49 // Itanium would exhibit anti-scalability. So I've chosen to reschedule
  50 // for worst latency for every instruction aiming for best *all-round*
  51 // performance.
  52
  53 // Q.   How much faster does it get?
  54 // A.   Here is the output from 'openssl speed rsa dsa' for vanilla
  55 //      0.9.6a compiled with gcc version 2.96 20000731 (Red Hat
  56 //      Linux 7.1 2.96-81):
  57 //
  58 //                        sign    verify    sign/s verify/s
  59 //      rsa  512 bits   0.0036s   0.0003s    275.3   2999.2
  60 //      rsa 1024 bits   0.0203s   0.0011s     49.3    894.1
  61 //      rsa 2048 bits   0.1331s   0.0040s      7.5    250.9
  62 //      rsa 4096 bits   0.9270s   0.0147s      1.1     68.1
  63 //                        sign    verify    sign/s verify/s
  64 //      dsa  512 bits   0.0035s   0.0043s    288.3    234.8
  65 //      dsa 1024 bits   0.0111s   0.0135s     90.0     74.2
  66 //
  67 //      And here is similar output but for this assembler
  68 //      implementation:-)
  69 //
  70 //                        sign    verify    sign/s verify/s
  71 //      rsa  512 bits   0.0021s   0.0001s    549.4   9638.5
  72 //      rsa 1024 bits   0.0055s   0.0002s    183.8   4481.1
  73 //      rsa 2048 bits   0.0244s   0.0006s     41.4   1726.3
  74 //      rsa 4096 bits   0.1295s   0.0018s      7.7    561.5
  75 //                        sign    verify    sign/s verify/s
  76 //      dsa  512 bits   0.0012s   0.0013s    891.9    756.6
  77 //      dsa 1024 bits   0.0023s   0.0028s    440.4    376.2
  78 //
  79 //      Yes, you may argue that it's not fair comparison as it's
  80 //      possible to craft the C implementation with BN_UMULT_HIGH
  81 //      inline assembler macro. But of course! Here is the output
  82 //      with the macro:
  83 //
  84 //                        sign    verify    sign/s verify/s
  85 //      rsa  512 bits   0.0020s   0.0002s    495.0   6561.0
  86 //      rsa 1024 bits   0.0086s   0.0004s    116.2   2235.7
  87 //      rsa 2048 bits   0.0519s   0.0015s     19.3    667.3
  88 //      rsa 4096 bits   0.3464s   0.0053s      2.9    187.7
  89 //                        sign    verify    sign/s verify/s
  90 //      dsa  512 bits   0.0016s   0.0020s    613.1    510.5
  91 //      dsa 1024 bits   0.0045s   0.0054s    221.0    183.9
  92 //
  93 //      My code is still way faster, huh:-) And I believe that even
  94 //      higher performance can be achieved. Note that as keys get
  95 //      longer, performance gain is larger. Why? According to the
  96 //      profiler there is another player in the field, namely
  97 //      BN_from_montgomery consuming larger and larger portion of CPU
  98 //      time as keysize decreases. I therefore consider putting effort
  99 //      to assembler implementation of the following routine:
 100 //
 101 //      void bn_mul_add_mont (BN_ULONG *rp,BN_ULONG *np,int nl,BN_ULONG n0)
 102 //      {
 103 //      int      i,j;
 104 //      BN_ULONG v;
 105 //
 106 //      for (i=0; i<nl; i++)
 107 //              {
 108 //              v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
 109 //              nrp++;
 110 //              rp++;
 111 //              if (((nrp[-1]+=v)&BN_MASK2) < v)
 112 //                      for (j=0; ((++nrp[j])&BN_MASK2) == 0; j++) ;
 113 //              }
 114 //      }
 115 //
 116 //      It might as well be beneficial to implement even combaX
 117 //      variants, as it appears as it can literally unleash the
 118 //      performance (see comment section to bn_mul_comba8 below).
 119 //
 120 //      And finally for your reference the output for 0.9.6a compiled
 121 //      with SGIcc version 0.01.0-12 (keep in mind that for the moment
 122 //      of this writing it's not possible to convince SGIcc to use
 123 //      BN_UMULT_HIGH inline assembler macro, yet the code is fast,
 124 //      i.e. for a compiler generated one:-):
 125 //
 126 //                        sign    verify    sign/s verify/s
 127 //      rsa  512 bits   0.0022s   0.0002s    452.7   5894.3
 128 //      rsa 1024 bits   0.0097s   0.0005s    102.7   2002.9
 129 //      rsa 2048 bits   0.0578s   0.0017s     17.3    600.2
 130 //      rsa 4096 bits   0.3838s   0.0061s      2.6    164.5
 131 //                        sign    verify    sign/s verify/s
 132 //      dsa  512 bits   0.0018s   0.0022s    547.3    459.6
 133 //      dsa 1024 bits   0.0051s   0.0062s    196.6    161.3
 134 //
 135 //      Oh! Benchmarks were performed on 733MHz Lion-class Itanium
 136 //      system running Redhat Linux 7.1 (very special thanks to Ray
 137 //      McCaffity of Williams Communications for providing an account).
 138 //
 139 // Q.   What's the heck with 'rum 1<<5' at the end of every function?
 140 // A.   Well, by clearing the "upper FP registers written" bit of the
 141 //      User Mask I want to excuse the kernel from preserving upper
 142 //      (f32-f128) FP register bank over process context switch, thus
 143 //      minimizing bus bandwidth consumption during the switch (i.e.
 144 //      after PKI opration completes and the program is off doing
 145 //      something else like bulk symmetric encryption). Having said
 146 //      this, I also want to point out that it might be good idea
 147 //      to compile the whole toolkit (as well as majority of the
 148 //      programs for that matter) with -mfixed-range=f32-f127 command
 149 //      line option. No, it doesn't prevent the compiler from writing
 150 //      to upper bank, but at least discourages to do so. If you don't
 151 //      like the idea you have the option to compile the module with
 152 //      -Drum=nop.m in command line.
 153 //
 154
 155 #if defined(_HPUX_SOURCE) && !defined(_LP64)
 156 #define ADDP    addp4
 157 #else
 158 #define ADDP    add
 159 #endif
 160
 161 #if 1
 162 //
 163 // bn_[add|sub]_words routines.
 164 //
 165 // Loops are spinning in 2*(n+5) ticks on Itanuim (provided that the
 166 // data reside in L1 cache, i.e. 2 ticks away). It's possible to
 167 // compress the epilogue and get down to 2*n+6, but at the cost of
 168 // scalability (the neat feature of this implementation is that it
 169 // shall automagically spin in n+5 on "wider" IA-64 implementations:-)
 170 // I consider that the epilogue is short enough as it is to trade tiny
 171 // performance loss on Itanium for scalability.
 172 //
 173 // BN_ULONG bn_add_words(BN_ULONG *rp, BN_ULONG *ap, BN_ULONG *bp,int num)
 174 //
 175 .global bn_add_words#
 176 .proc   bn_add_words#
 177 .align  64
 178 .skip   32      // makes the loop body aligned at 64-byte boundary
 179 bn_add_words:
 180         .prologue
 181         .save   ar.pfs,r2
 182 { .mii; alloc           r2=ar.pfs,4,12,0,16
 183         cmp4.le         p6,p0=r35,r0    };;
 184 { .mfb; mov             r8=r0                   // return value
 185 (p6)    br.ret.spnt.many        b0      };;
 186
 187 { .mib; sub             r10=r35,r0,1
 188         .save   ar.lc,r3
 189         mov             r3=ar.lc
 190         brp.loop.imp    .L_bn_add_words_ctop,.L_bn_add_words_cend-16
 191                                         }
 192 { .mib; ADDP            r14=0,r32               // rp
 193         .save   pr,r9
 194         mov             r9=pr           };;
 195         .body
 196 { .mii; ADDP            r15=0,r33               // ap
 197         mov             ar.lc=r10
 198         mov             ar.ec=6         }
 199 { .mib; ADDP            r16=0,r34               // bp
 200         mov             pr.rot=1<<16    };;
 201
 202 .L_bn_add_words_ctop:
 203 { .mii; (p16)   ld8             r32=[r16],8       // b=*(bp++)
 204         (p18)   add             r39=r37,r34
 205         (p19)   cmp.ltu.unc     p56,p0=r40,r38  }
 206 { .mfb; (p0)    nop.m           0x0
 207         (p0)    nop.f           0x0
 208         (p0)    nop.b           0x0             }
 209 { .mii; (p16)   ld8             r35=[r15],8       // a=*(ap++)
 210         (p58)   cmp.eq.or       p57,p0=-1,r41     // (p20)
 211         (p58)   add             r41=1,r41       } // (p20)
 212 { .mfb; (p21)   st8             [r14]=r42,8       // *(rp++)=r
 213         (p0)    nop.f           0x0
 214         br.ctop.sptk    .L_bn_add_words_ctop    };;
 215 .L_bn_add_words_cend:
 216
 217 { .mii;
 218 (p59)   add             r8=1,r8         // return value
 219         mov             pr=r9,0x1ffff
 220         mov             ar.lc=r3        }
 221 { .mbb; nop.b           0x0
 222         br.ret.sptk.many        b0      };;
 223 .endp   bn_add_words#
 224
 225 //
 226 // BN_ULONG bn_sub_words(BN_ULONG *rp, BN_ULONG *ap, BN_ULONG *bp,int num)
 227 //
 228 .global bn_sub_words#
 229 .proc   bn_sub_words#
 230 .align  64
 231 .skip   32      // makes the loop body aligned at 64-byte boundary
 232 bn_sub_words:
 233         .prologue
 234         .save   ar.pfs,r2
 235 { .mii; alloc           r2=ar.pfs,4,12,0,16
 236         cmp4.le         p6,p0=r35,r0    };;
 237 { .mfb; mov             r8=r0                   // return value
 238 (p6)    br.ret.spnt.many        b0      };;
 239
 240 { .mib; sub             r10=r35,r0,1
 241         .save   ar.lc,r3
 242         mov             r3=ar.lc
 243         brp.loop.imp    .L_bn_sub_words_ctop,.L_bn_sub_words_cend-16
 244                                         }
 245 { .mib; ADDP            r14=0,r32               // rp
 246         .save   pr,r9
 247         mov             r9=pr           };;
 248         .body
 249 { .mii; ADDP            r15=0,r33               // ap
 250         mov             ar.lc=r10
 251         mov             ar.ec=6         }
 252 { .mib; ADDP            r16=0,r34               // bp
 253         mov             pr.rot=1<<16    };;
 254
 255 .L_bn_sub_words_ctop:
 256 { .mii; (p16)   ld8             r32=[r16],8       // b=*(bp++)
 257         (p18)   sub             r39=r37,r34
 258         (p19)   cmp.gtu.unc     p56,p0=r40,r38  }
 259 { .mfb; (p0)    nop.m           0x0
 260         (p0)    nop.f           0x0
 261         (p0)    nop.b           0x0             }
 262 { .mii; (p16)   ld8             r35=[r15],8       // a=*(ap++)
 263         (p58)   cmp.eq.or       p57,p0=0,r41      // (p20)
 264         (p58)   add             r41=-1,r41      } // (p20)
 265 { .mbb; (p21)   st8             [r14]=r42,8       // *(rp++)=r
 266         (p0)    nop.b           0x0
 267         br.ctop.sptk    .L_bn_sub_words_ctop    };;
 268 .L_bn_sub_words_cend:
 269
 270 { .mii;
 271 (p59)   add             r8=1,r8         // return value
 272         mov             pr=r9,0x1ffff
 273         mov             ar.lc=r3        }
 274 { .mbb; nop.b           0x0
 275         br.ret.sptk.many        b0      };;
 276 .endp   bn_sub_words#
 277 #endif
 278
 279 #if 0
 280 #define XMA_TEMPTATION
 281 #endif
 282
 283 #if 1
 284 //
 285 // BN_ULONG bn_mul_words(BN_ULONG *rp, BN_ULONG *ap, int num, BN_ULONG w)
 286 //
 287 .global bn_mul_words#
 288 .proc   bn_mul_words#
 289 .align  64
 290 .skip   32      // makes the loop body aligned at 64-byte boundary
 291 bn_mul_words:
 292         .prologue
 293         .save   ar.pfs,r2
 294 #ifdef XMA_TEMPTATION
 295 { .mfi; alloc           r2=ar.pfs,4,0,0,0       };;
 296 #else
 297 { .mfi; alloc           r2=ar.pfs,4,12,0,16     };;
 298 #endif
 299 { .mib; mov             r8=r0                   // return value
 300         cmp4.le         p6,p0=r34,r0
 301 (p6)    br.ret.spnt.many        b0              };;
 302
 303 { .mii; sub     r10=r34,r0,1
 304         .save   ar.lc,r3
 305         mov     r3=ar.lc
 306         .save   pr,r9
 307         mov     r9=pr                   };;
 308
 309         .body
 310 { .mib; setf.sig        f8=r35  // w
 311         mov             pr.rot=0x800001<<16
 312                         // ------^----- serves as (p50) at first (p27)
 313         brp.loop.imp    .L_bn_mul_words_ctop,.L_bn_mul_words_cend-16
 314                                         }
 315
 316 #ifndef XMA_TEMPTATION
 317
 318 { .mmi; ADDP            r14=0,r32       // rp
 319         ADDP            r15=0,r33       // ap
 320         mov             ar.lc=r10       }
 321 { .mmi; mov             r40=0           // serves as r35 at first (p27)
 322         mov             ar.ec=13        };;
 323
 324 // This loop spins in 2*(n+12) ticks. It's scheduled for data in Itanium
 325 // L2 cache (i.e. 9 ticks away) as floating point load/store instructions
 326 // bypass L1 cache and L2 latency is actually best-case scenario for
 327 // ldf8. The loop is not scalable and shall run in 2*(n+12) even on
 328 // "wider" IA-64 implementations. It's a trade-off here. n+24 loop
 329 // would give us ~5% in *overall* performance improvement on "wider"
 330 // IA-64, but would hurt Itanium for about same because of longer
 331 // epilogue. As it's a matter of few percents in either case I've
 332 // chosen to trade the scalability for development time (you can see
 333 // this very instruction sequence in bn_mul_add_words loop which in
 334 // turn is scalable).
 335 .L_bn_mul_words_ctop:
 336 { .mfi; (p25)   getf.sig        r36=f52                 // low
 337         (p21)   xmpy.lu         f48=f37,f8
 338         (p28)   cmp.ltu         p54,p50=r41,r39 }
 339 { .mfi; (p16)   ldf8            f32=[r15],8
 340         (p21)   xmpy.hu         f40=f37,f8
 341         (p0)    nop.i           0x0             };;
 342 { .mii; (p25)   getf.sig        r32=f44                 // high
 343         .pred.rel       "mutex",p50,p54
 344         (p50)   add             r40=r38,r35             // (p27)
 345         (p54)   add             r40=r38,r35,1   }       // (p27)
 346 { .mfb; (p28)   st8             [r14]=r41,8
 347         (p0)    nop.f           0x0
 348         br.ctop.sptk    .L_bn_mul_words_ctop    };;
 349 .L_bn_mul_words_cend:
 350
 351 { .mii; nop.m           0x0
 352 .pred.rel       "mutex",p51,p55
 353 (p51)   add             r8=r36,r0
 354 (p55)   add             r8=r36,r0,1     }
 355 { .mfb; nop.m   0x0
 356         nop.f   0x0
 357         nop.b   0x0                     }
 358
 359 #else   // XMA_TEMPTATION
 360
 361         setf.sig        f37=r0  // serves as carry at (p18) tick
 362         mov             ar.lc=r10
 363         mov             ar.ec=5;;
 364
 365 // Most of you examining this code very likely wonder why in the name
 366 // of Intel the following loop is commented out? Indeed, it looks so
 367 // neat that you find it hard to believe that it's something wrong
 368 // with it, right? The catch is that every iteration depends on the
 369 // result from previous one and the latter isn't available instantly.
 370 // The loop therefore spins at the latency of xma minus 1, or in other
 371 // words at 6*(n+4) ticks:-( Compare to the "production" loop above
 372 // that runs in 2*(n+11) where the low latency problem is worked around
 373 // by moving the dependency to one-tick latent integer ALU. Note that
 374 // "distance" between ldf8 and xma is not latency of ldf8, but the
 375 // *difference* between xma and ldf8 latencies.
 376 .L_bn_mul_words_ctop:
 377 { .mfi; (p16)   ldf8            f32=[r33],8
 378         (p18)   xma.hu          f38=f34,f8,f39  }
 379 { .mfb; (p20)   stf8            [r32]=f37,8
 380         (p18)   xma.lu          f35=f34,f8,f39
 381         br.ctop.sptk    .L_bn_mul_words_ctop    };;
 382 .L_bn_mul_words_cend:
 383
 384         getf.sig        r8=f41          // the return value
 385
 386 #endif  // XMA_TEMPTATION
 387
 388 { .mii; nop.m           0x0
 389         mov             pr=r9,0x1ffff
 390         mov             ar.lc=r3        }
 391 { .mfb; rum             1<<5            // clear um.mfh
 392         nop.f           0x0
 393         br.ret.sptk.many        b0      };;
 394 .endp   bn_mul_words#
 395 #endif
 396
 397 #if 1
 398 //
 399 // BN_ULONG bn_mul_add_words(BN_ULONG *rp, BN_ULONG *ap, int num, BN_ULONG w)
 400 //
 401 .global bn_mul_add_words#
 402 .proc   bn_mul_add_words#
 403 .align  64
 404 .skip   48      // makes the loop body aligned at 64-byte boundary
 405 bn_mul_add_words:
 406         .prologue
 407         .save   ar.pfs,r2
 408 { .mmi; alloc           r2=ar.pfs,4,4,0,8
 409         cmp4.le         p6,p0=r34,r0
 410         .save   ar.lc,r3
 411         mov             r3=ar.lc        };;
 412 { .mib; mov             r8=r0           // return value
 413         sub             r10=r34,r0,1
 414 (p6)    br.ret.spnt.many        b0      };;
 415
 416 { .mib; setf.sig        f8=r35          // w
 417         .save   pr,r9
 418         mov             r9=pr
 419         brp.loop.imp    .L_bn_mul_add_words_ctop,.L_bn_mul_add_words_cend-16
 420                                         }
 421         .body
 422 { .mmi; ADDP            r14=0,r32       // rp
 423         ADDP            r15=0,r33       // ap
 424         mov             ar.lc=r10       }
 425 { .mii; ADDP            r16=0,r32       // rp copy
 426         mov             pr.rot=0x2001<<16
 427                         // ------^----- serves as (p40) at first (p27)
 428         mov             ar.ec=11        };;
 429
 430 // This loop spins in 3*(n+10) ticks on Itanium and in 2*(n+10) on
 431 // Itanium 2. Yes, unlike previous versions it scales:-) Previous
 432 // version was performing *all* additions in IALU and was starving
 433 // for those even on Itanium 2. In this version one addition is
 434 // moved to FPU and is folded with multiplication. This is at cost
 435 // of propagating the result from previous call to this subroutine
 436 // to L2 cache... In other words negligible even for shorter keys.
 437 // *Overall* performance improvement [over previous version] varies
 438 // from 11 to 22 percent depending on key length.
 439 .L_bn_mul_add_words_ctop:
 440 .pred.rel       "mutex",p40,p42
 441 { .mfi; (p23)   getf.sig        r36=f45                 // low
 442         (p20)   xma.lu          f42=f36,f8,f50          // low
 443         (p40)   add             r39=r39,r35     }       // (p27)
 444 { .mfi; (p16)   ldf8            f32=[r15],8             // *(ap++)
 445         (p20)   xma.hu          f36=f36,f8,f50          // high
 446         (p42)   add             r39=r39,r35,1   };;     // (p27)
 447 { .mmi; (p24)   getf.sig        r32=f40                 // high
 448         (p16)   ldf8            f46=[r16],8             // *(rp1++)
 449         (p40)   cmp.ltu         p41,p39=r39,r35 }       // (p27)
 450 { .mib; (p26)   st8             [r14]=r39,8             // *(rp2++)
 451         (p42)   cmp.leu         p41,p39=r39,r35         // (p27)
 452         br.ctop.sptk    .L_bn_mul_add_words_ctop};;
 453 .L_bn_mul_add_words_cend:
 454
 455 { .mmi; .pred.rel       "mutex",p40,p42
 456 (p40)   add             r8=r35,r0
 457 (p42)   add             r8=r35,r0,1
 458         mov             pr=r9,0x1ffff   }
 459 { .mib; rum             1<<5            // clear um.mfh
 460         mov             ar.lc=r3
 461         br.ret.sptk.many        b0      };;
 462 .endp   bn_mul_add_words#
 463 #endif
 464
 465 #if 1
 466 //
 467 // void bn_sqr_words(BN_ULONG *rp, BN_ULONG *ap, int num)
 468 //
 469 .global bn_sqr_words#
 470 .proc   bn_sqr_words#
 471 .align  64
 472 .skip   32      // makes the loop body aligned at 64-byte boundary
 473 bn_sqr_words:
 474         .prologue
 475         .save   ar.pfs,r2
 476 { .mii; alloc           r2=ar.pfs,3,0,0,0
 477         sxt4            r34=r34         };;
 478 { .mii; cmp.le          p6,p0=r34,r0
 479         mov             r8=r0           }       // return value
 480 { .mfb; ADDP            r32=0,r32
 481         nop.f           0x0
 482 (p6)    br.ret.spnt.many        b0      };;
 483
 484 { .mii; sub     r10=r34,r0,1
 485         .save   ar.lc,r3
 486         mov     r3=ar.lc
 487         .save   pr,r9
 488         mov     r9=pr                   };;
 489
 490         .body
 491 { .mib; ADDP            r33=0,r33
 492         mov             pr.rot=1<<16
 493         brp.loop.imp    .L_bn_sqr_words_ctop,.L_bn_sqr_words_cend-16
 494                                         }
 495 { .mii; add             r34=8,r32
 496         mov             ar.lc=r10
 497         mov             ar.ec=18        };;
 498
 499 // 2*(n+17) on Itanium, (n+17) on "wider" IA-64 implementations. It's
 500 // possible to compress the epilogue (I'm getting tired to write this
 501 // comment over and over) and get down to 2*n+16 at the cost of
 502 // scalability. The decision will very likely be reconsidered after the
 503 // benchmark program is profiled. I.e. if perfomance gain on Itanium
 504 // will appear larger than loss on "wider" IA-64, then the loop should
 505 // be explicitly split and the epilogue compressed.
 506 .L_bn_sqr_words_ctop:
 507 { .mfi; (p16)   ldf8            f32=[r33],8
 508         (p25)   xmpy.lu         f42=f41,f41
 509         (p0)    nop.i           0x0             }
 510 { .mib; (p33)   stf8            [r32]=f50,16
 511         (p0)    nop.i           0x0
 512         (p0)    nop.b           0x0             }
 513 { .mfi; (p0)    nop.m           0x0
 514         (p25)   xmpy.hu         f52=f41,f41
 515         (p0)    nop.i           0x0             }
 516 { .mib; (p33)   stf8            [r34]=f60,16
 517         (p0)    nop.i           0x0
 518         br.ctop.sptk    .L_bn_sqr_words_ctop    };;
 519 .L_bn_sqr_words_cend:
 520
 521 { .mii; nop.m           0x0
 522         mov             pr=r9,0x1ffff
 523         mov             ar.lc=r3        }
 524 { .mfb; rum             1<<5            // clear um.mfh
 525         nop.f           0x0
 526         br.ret.sptk.many        b0      };;
 527 .endp   bn_sqr_words#
 528 #endif
 529
 530 #if 1
 531 // Apparently we win nothing by implementing special bn_sqr_comba8.
 532 // Yes, it is possible to reduce the number of multiplications by
 533 // almost factor of two, but then the amount of additions would
 534 // increase by factor of two (as we would have to perform those
 535 // otherwise performed by xma ourselves). Normally we would trade
 536 // anyway as multiplications are way more expensive, but not this
 537 // time... Multiplication kernel is fully pipelined and as we drain
 538 // one 128-bit multiplication result per clock cycle multiplications
 539 // are effectively as inexpensive as additions. Special implementation
 540 // might become of interest for "wider" IA-64 implementation as you'll
 541 // be able to get through the multiplication phase faster (there won't
 542 // be any stall issues as discussed in the commentary section below and
 543 // you therefore will be able to employ all 4 FP units)... But these
 544 // Itanium days it's simply too hard to justify the effort so I just
 545 // drop down to bn_mul_comba8 code:-)
 546 //
 547 // void bn_sqr_comba8(BN_ULONG *r, BN_ULONG *a)
 548 //
 549 .global bn_sqr_comba8#
 550 .proc   bn_sqr_comba8#
 551 .align  64
 552 bn_sqr_comba8:
 553         .prologue
 554         .save   ar.pfs,r2
 555 #if defined(_HPUX_SOURCE) && !defined(_LP64)
 556 { .mii; alloc   r2=ar.pfs,2,1,0,0
 557         addp4   r33=0,r33
 558         addp4   r32=0,r32               };;
 559 { .mii;
 560 #else
 561 { .mii; alloc   r2=ar.pfs,2,1,0,0
 562 #endif
 563         mov     r34=r33
 564         add     r14=8,r33               };;
 565         .body
 566 { .mii; add     r17=8,r34
 567         add     r15=16,r33
 568         add     r18=16,r34              }
 569 { .mfb; add     r16=24,r33
 570         br      .L_cheat_entry_point8   };;
 571 .endp   bn_sqr_comba8#
 572 #endif
 573
 574 #if 1
 575 // I've estimated this routine to run in ~120 ticks, but in reality
 576 // (i.e. according to ar.itc) it takes ~160 ticks. Are those extra
 577 // cycles consumed for instructions fetch? Or did I misinterpret some
 578 // clause in Itanium µ-architecture manual? Comments are welcomed and
 579 // highly appreciated.
 580 //
 581 // On Itanium 2 it takes ~190 ticks. This is because of stalls on
 582 // result from getf.sig. I do nothing about it at this point for
 583 // reasons depicted below.
 584 //
 585 // However! It should be noted that even 160 ticks is darn good result
 586 // as it's over 10 (yes, ten, spelled as t-e-n) times faster than the
 587 // C version (compiled with gcc with inline assembler). I really
 588 // kicked compiler's butt here, didn't I? Yeah! This brings us to the
 589 // following statement. It's damn shame that this routine isn't called
 590 // very often nowadays! According to the profiler most CPU time is
 591 // consumed by bn_mul_add_words called from BN_from_montgomery. In
 592 // order to estimate what we're missing, I've compared the performance
 593 // of this routine against "traditional" implementation, i.e. against
 594 // following routine:
 595 //
 596 // void bn_mul_comba8(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
 597 // {    r[ 8]=bn_mul_words(    &(r[0]),a,8,b[0]);
 598 //      r[ 9]=bn_mul_add_words(&(r[1]),a,8,b[1]);
 599 //      r[10]=bn_mul_add_words(&(r[2]),a,8,b[2]);
 600 //      r[11]=bn_mul_add_words(&(r[3]),a,8,b[3]);
 601 //      r[12]=bn_mul_add_words(&(r[4]),a,8,b[4]);
 602 //      r[13]=bn_mul_add_words(&(r[5]),a,8,b[5]);
 603 //      r[14]=bn_mul_add_words(&(r[6]),a,8,b[6]);
 604 //      r[15]=bn_mul_add_words(&(r[7]),a,8,b[7]);
 605 // }
 606 //
 607 // The one below is over 8 times faster than the one above:-( Even
 608 // more reasons to "combafy" bn_mul_add_mont...
 609 //
 610 // And yes, this routine really made me wish there were an optimizing
 611 // assembler! It also feels like it deserves a dedication.
 612 //
 613 //      To my wife for being there and to my kids...
 614 //
 615 // void bn_mul_comba8(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
 616 //
 617 #define carry1  r14
 618 #define carry2  r15
 619 #define carry3  r34
 620 .global bn_mul_comba8#
 621 .proc   bn_mul_comba8#
 622 .align  64
 623 bn_mul_comba8:
 624         .prologue
 625         .save   ar.pfs,r2
 626 #if defined(_HPUX_SOURCE) && !defined(_LP64)
 627 { .mii; alloc   r2=ar.pfs,3,0,0,0
 628         addp4   r33=0,r33
 629         addp4   r34=0,r34               };;
 630 { .mii; addp4   r32=0,r32
 631 #else
 632 { .mii; alloc   r2=ar.pfs,3,0,0,0
 633 #endif
 634         add     r14=8,r33
 635         add     r17=8,r34               }
 636         .body
 637 { .mii; add     r15=16,r33
 638         add     r18=16,r34
 639         add     r16=24,r33              }
 640 .L_cheat_entry_point8:
 641 { .mmi; add     r19=24,r34
 642
 643         ldf8    f32=[r33],32            };;
 644
 645 { .mmi; ldf8    f120=[r34],32
 646         ldf8    f121=[r17],32           }
 647 { .mmi; ldf8    f122=[r18],32
 648         ldf8    f123=[r19],32           };;
 649 { .mmi; ldf8    f124=[r34]
 650         ldf8    f125=[r17]              }
 651 { .mmi; ldf8    f126=[r18]
 652         ldf8    f127=[r19]              }
 653
 654 { .mmi; ldf8    f33=[r14],32
 655         ldf8    f34=[r15],32            }
 656 { .mmi; ldf8    f35=[r16],32;;
 657         ldf8    f36=[r33]               }
 658 { .mmi; ldf8    f37=[r14]
 659         ldf8    f38=[r15]               }
 660 { .mfi; ldf8    f39=[r16]
 661 // -------\ Entering multiplier's heaven /-------
 662 // ------------\                    /------------
 663 // -----------------\          /-----------------
 664 // ----------------------\/----------------------
 665                 xma.hu  f41=f32,f120,f0         }
 666 { .mfi;         xma.lu  f40=f32,f120,f0         };; // (*)
 667 { .mfi;         xma.hu  f51=f32,f121,f0         }
 668 { .mfi;         xma.lu  f50=f32,f121,f0         };;
 669 { .mfi;         xma.hu  f61=f32,f122,f0         }
 670 { .mfi;         xma.lu  f60=f32,f122,f0         };;
 671 { .mfi;         xma.hu  f71=f32,f123,f0         }
 672 { .mfi;         xma.lu  f70=f32,f123,f0         };;
 673 { .mfi;         xma.hu  f81=f32,f124,f0         }
 674 { .mfi;         xma.lu  f80=f32,f124,f0         };;
 675 { .mfi;         xma.hu  f91=f32,f125,f0         }
 676 { .mfi;         xma.lu  f90=f32,f125,f0         };;
 677 { .mfi;         xma.hu  f101=f32,f126,f0        }
 678 { .mfi;         xma.lu  f100=f32,f126,f0        };;
 679 { .mfi;         xma.hu  f111=f32,f127,f0        }
 680 { .mfi;         xma.lu  f110=f32,f127,f0        };;//
 681 // (*)  You can argue that splitting at every second bundle would
 682 //      prevent "wider" IA-64 implementations from achieving the peak
 683 //      performance. Well, not really... The catch is that if you
 684 //      intend to keep 4 FP units busy by splitting at every fourth
 685 //      bundle and thus perform these 16 multiplications in 4 ticks,
 686 //      the first bundle *below* would stall because the result from
 687 //      the first xma bundle *above* won't be available for another 3
 688 //      ticks (if not more, being an optimist, I assume that "wider"
 689 //      implementation will have same latency:-). This stall will hold
 690 //      you back and the performance would be as if every second bundle
 691 //      were split *anyway*...
 692 { .mfi; getf.sig        r16=f40
 693                 xma.hu  f42=f33,f120,f41
 694         add             r33=8,r32               }
 695 { .mfi;         xma.lu  f41=f33,f120,f41        };;
 696 { .mfi; getf.sig        r24=f50
 697                 xma.hu  f52=f33,f121,f51        }
 698 { .mfi;         xma.lu  f51=f33,f121,f51        };;
 699 { .mfi; st8             [r32]=r16,16
 700                 xma.hu  f62=f33,f122,f61        }
 701 { .mfi;         xma.lu  f61=f33,f122,f61        };;
 702 { .mfi;         xma.hu  f72=f33,f123,f71        }
 703 { .mfi;         xma.lu  f71=f33,f123,f71        };;
 704 { .mfi;         xma.hu  f82=f33,f124,f81        }
 705 { .mfi;         xma.lu  f81=f33,f124,f81        };;
 706 { .mfi;         xma.hu  f92=f33,f125,f91        }
 707 { .mfi;         xma.lu  f91=f33,f125,f91        };;
 708 { .mfi;         xma.hu  f102=f33,f126,f101      }
 709 { .mfi;         xma.lu  f101=f33,f126,f101      };;
 710 { .mfi;         xma.hu  f112=f33,f127,f111      }
 711 { .mfi;         xma.lu  f111=f33,f127,f111      };;//
 712 //-------------------------------------------------//
 713 { .mfi; getf.sig        r25=f41
 714                 xma.hu  f43=f34,f120,f42        }
 715 { .mfi;         xma.lu  f42=f34,f120,f42        };;
 716 { .mfi; getf.sig        r16=f60
 717                 xma.hu  f53=f34,f121,f52        }
 718 { .mfi;         xma.lu  f52=f34,f121,f52        };;
 719 { .mfi; getf.sig        r17=f51
 720                 xma.hu  f63=f34,f122,f62
 721         add             r25=r25,r24             }
 722 { .mfi;         xma.lu  f62=f34,f122,f62
 723         mov             carry1=0                };;
 724 { .mfi; cmp.ltu         p6,p0=r25,r24
 725                 xma.hu  f73=f34,f123,f72        }
 726 { .mfi;         xma.lu  f72=f34,f123,f72        };;
 727 { .mfi; st8             [r33]=r25,16
 728                 xma.hu  f83=f34,f124,f82
 729 (p6)    add             carry1=1,carry1         }
 730 { .mfi;         xma.lu  f82=f34,f124,f82        };;
 731 { .mfi;         xma.hu  f93=f34,f125,f92        }
 732 { .mfi;         xma.lu  f92=f34,f125,f92        };;
 733 { .mfi;         xma.hu  f103=f34,f126,f102      }
 734 { .mfi;         xma.lu  f102=f34,f126,f102      };;
 735 { .mfi;         xma.hu  f113=f34,f127,f112      }
 736 { .mfi;         xma.lu  f112=f34,f127,f112      };;//
 737 //-------------------------------------------------//
 738 { .mfi; getf.sig        r18=f42
 739                 xma.hu  f44=f35,f120,f43
 740         add             r17=r17,r16             }
 741 { .mfi;         xma.lu  f43=f35,f120,f43        };;
 742 { .mfi; getf.sig        r24=f70
 743                 xma.hu  f54=f35,f121,f53        }
 744 { .mfi; mov             carry2=0
 745                 xma.lu  f53=f35,f121,f53        };;
 746 { .mfi; getf.sig        r25=f61
 747                 xma.hu  f64=f35,f122,f63
 748         cmp.ltu         p7,p0=r17,r16           }
 749 { .mfi; add             r18=r18,r17
 750                 xma.lu  f63=f35,f122,f63        };;
 751 { .mfi; getf.sig        r26=f52
 752                 xma.hu  f74=f35,f123,f73
 753 (p7)    add             carry2=1,carry2         }
 754 { .mfi; cmp.ltu         p7,p0=r18,r17
 755                 xma.lu  f73=f35,f123,f73
 756         add             r18=r18,carry1          };;
 757 { .mfi;
 758                 xma.hu  f84=f35,f124,f83
 759 (p7)    add             carry2=1,carry2         }
 760 { .mfi; cmp.ltu         p7,p0=r18,carry1
 761                 xma.lu  f83=f35,f124,f83        };;
 762 { .mfi; st8             [r32]=r18,16
 763                 xma.hu  f94=f35,f125,f93
 764 (p7)    add             carry2=1,carry2         }
 765 { .mfi;         xma.lu  f93=f35,f125,f93        };;
 766 { .mfi;         xma.hu  f104=f35,f126,f103      }
 767 { .mfi;         xma.lu  f103=f35,f126,f103      };;
 768 { .mfi;         xma.hu  f114=f35,f127,f113      }
 769 { .mfi; mov             carry1=0
 770                 xma.lu  f113=f35,f127,f113
 771         add             r25=r25,r24             };;//
 772 //-------------------------------------------------//
 773 { .mfi; getf.sig        r27=f43
 774                 xma.hu  f45=f36,f120,f44
 775         cmp.ltu         p6,p0=r25,r24           }
 776 { .mfi;         xma.lu  f44=f36,f120,f44
 777         add             r26=r26,r25             };;
 778 { .mfi; getf.sig        r16=f80
 779                 xma.hu  f55=f36,f121,f54
 780 (p6)    add             carry1=1,carry1         }
 781 { .mfi;         xma.lu  f54=f36,f121,f54        };;
 782 { .mfi; getf.sig        r17=f71
 783                 xma.hu  f65=f36,f122,f64
 784         cmp.ltu         p6,p0=r26,r25           }
 785 { .mfi;         xma.lu  f64=f36,f122,f64
 786         add             r27=r27,r26             };;
 787 { .mfi; getf.sig        r18=f62
 788                 xma.hu  f75=f36,f123,f74
 789 (p6)    add             carry1=1,carry1         }
 790 { .mfi; cmp.ltu         p6,p0=r27,r26
 791                 xma.lu  f74=f36,f123,f74
 792         add             r27=r27,carry2          };;
 793 { .mfi; getf.sig        r19=f53
 794                 xma.hu  f85=f36,f124,f84
 795 (p6)    add             carry1=1,carry1         }
 796 { .mfi;         xma.lu  f84=f36,f124,f84
 797         cmp.ltu         p6,p0=r27,carry2        };;
 798 { .mfi; st8             [r33]=r27,16
 799                 xma.hu  f95=f36,f125,f94
 800 (p6)    add             carry1=1,carry1         }
 801 { .mfi;         xma.lu  f94=f36,f125,f94        };;
 802 { .mfi;         xma.hu  f105=f36,f126,f104      }
 803 { .mfi; mov             carry2=0
 804                 xma.lu  f104=f36,f126,f104
 805         add             r17=r17,r16             };;
 806 { .mfi;         xma.hu  f115=f36,f127,f114
 807         cmp.ltu         p7,p0=r17,r16           }
 808 { .mfi;         xma.lu  f114=f36,f127,f114
 809         add             r18=r18,r17             };;//
 810 //-------------------------------------------------//
 811 { .mfi; getf.sig        r20=f44
 812                 xma.hu  f46=f37,f120,f45
 813 (p7)    add             carry2=1,carry2         }
 814 { .mfi; cmp.ltu         p7,p0=r18,r17
 815                 xma.lu  f45=f37,f120,f45
 816         add             r19=r19,r18             };;
 817 { .mfi; getf.sig        r24=f90
 818                 xma.hu  f56=f37,f121,f55        }
 819 { .mfi;         xma.lu  f55=f37,f121,f55        };;
 820 { .mfi; getf.sig        r25=f81
 821                 xma.hu  f66=f37,f122,f65
 822 (p7)    add             carry2=1,carry2         }
 823 { .mfi; cmp.ltu         p7,p0=r19,r18
 824                 xma.lu  f65=f37,f122,f65
 825         add             r20=r20,r19             };;
 826 { .mfi; getf.sig        r26=f72
 827                 xma.hu  f76=f37,f123,f75
 828 (p7)    add             carry2=1,carry2         }
 829 { .mfi; cmp.ltu         p7,p0=r20,r19
 830                 xma.lu  f75=f37,f123,f75
 831         add             r20=r20,carry1          };;
 832 { .mfi; getf.sig        r27=f63
 833                 xma.hu  f86=f37,f124,f85
 834 (p7)    add             carry2=1,carry2         }
 835 { .mfi;         xma.lu  f85=f37,f124,f85
 836         cmp.ltu         p7,p0=r20,carry1        };;
 837 { .mfi; getf.sig        r28=f54
 838                 xma.hu  f96=f37,f125,f95
 839 (p7)    add             carry2=1,carry2         }
 840 { .mfi; st8             [r32]=r20,16
 841                 xma.lu  f95=f37,f125,f95        };;
 842 { .mfi;         xma.hu  f106=f37,f126,f105      }
 843 { .mfi; mov             carry1=0
 844                 xma.lu  f105=f37,f126,f105
 845         add             r25=r25,r24             };;
 846 { .mfi;         xma.hu  f116=f37,f127,f115
 847         cmp.ltu         p6,p0=r25,r24           }
 848 { .mfi;         xma.lu  f115=f37,f127,f115
 849         add             r26=r26,r25             };;//
 850 //-------------------------------------------------//
 851 { .mfi; getf.sig        r29=f45
 852                 xma.hu  f47=f38,f120,f46
 853 (p6)    add             carry1=1,carry1         }
 854 { .mfi; cmp.ltu         p6,p0=r26,r25
 855                 xma.lu  f46=f38,f120,f46
 856         add             r27=r27,r26             };;
 857 { .mfi; getf.sig        r16=f100
 858                 xma.hu  f57=f38,f121,f56
 859 (p6)    add             carry1=1,carry1         }
 860 { .mfi; cmp.ltu         p6,p0=r27,r26
 861                 xma.lu  f56=f38,f121,f56
 862         add             r28=r28,r27             };;
 863 { .mfi; getf.sig        r17=f91
 864                 xma.hu  f67=f38,f122,f66
 865 (p6)    add             carry1=1,carry1         }
 866 { .mfi; cmp.ltu         p6,p0=r28,r27
 867                 xma.lu  f66=f38,f122,f66
 868         add             r29=r29,r28             };;
 869 { .mfi; getf.sig        r18=f82
 870                 xma.hu  f77=f38,f123,f76
 871 (p6)    add             carry1=1,carry1         }
 872 { .mfi; cmp.ltu         p6,p0=r29,r28
 873                 xma.lu  f76=f38,f123,f76
 874         add             r29=r29,carry2          };;
 875 { .mfi; getf.sig        r19=f73
 876                 xma.hu  f87=f38,f124,f86
 877 (p6)    add             carry1=1,carry1         }
 878 { .mfi;         xma.lu  f86=f38,f124,f86
 879         cmp.ltu         p6,p0=r29,carry2        };;
 880 { .mfi; getf.sig        r20=f64
 881                 xma.hu  f97=f38,f125,f96
 882 (p6)    add             carry1=1,carry1         }
 883 { .mfi; st8             [r33]=r29,16
 884                 xma.lu  f96=f38,f125,f96        };;
 885 { .mfi; getf.sig        r21=f55
 886                 xma.hu  f107=f38,f126,f106      }
 887 { .mfi; mov             carry2=0
 888                 xma.lu  f106=f38,f126,f106
 889         add             r17=r17,r16             };;
 890 { .mfi;         xma.hu  f117=f38,f127,f116
 891         cmp.ltu         p7,p0=r17,r16           }
 892 { .mfi;         xma.lu  f116=f38,f127,f116
 893         add             r18=r18,r17             };;//
 894 //-------------------------------------------------//
 895 { .mfi; getf.sig        r22=f46
 896                 xma.hu  f48=f39,f120,f47
 897 (p7)    add             carry2=1,carry2         }
 898 { .mfi; cmp.ltu         p7,p0=r18,r17
 899                 xma.lu  f47=f39,f120,f47
 900         add             r19=r19,r18             };;
 901 { .mfi; getf.sig        r24=f110
 902                 xma.hu  f58=f39,f121,f57
 903 (p7)    add             carry2=1,carry2         }
 904 { .mfi; cmp.ltu         p7,p0=r19,r18
 905                 xma.lu  f57=f39,f121,f57
 906         add             r20=r20,r19             };;
 907 { .mfi; getf.sig        r25=f101
 908                 xma.hu  f68=f39,f122,f67
 909 (p7)    add             carry2=1,carry2         }
 910 { .mfi; cmp.ltu         p7,p0=r20,r19
 911                 xma.lu  f67=f39,f122,f67
 912         add             r21=r21,r20             };;
 913 { .mfi; getf.sig        r26=f92
 914                 xma.hu  f78=f39,f123,f77
 915 (p7)    add             carry2=1,carry2         }
 916 { .mfi; cmp.ltu         p7,p0=r21,r20
 917                 xma.lu  f77=f39,f123,f77
 918         add             r22=r22,r21             };;
 919 { .mfi; getf.sig        r27=f83
 920                 xma.hu  f88=f39,f124,f87
 921 (p7)    add             carry2=1,carry2         }
 922 { .mfi; cmp.ltu         p7,p0=r22,r21
 923                 xma.lu  f87=f39,f124,f87
 924         add             r22=r22,carry1          };;
 925 { .mfi; getf.sig        r28=f74
 926                 xma.hu  f98=f39,f125,f97
 927 (p7)    add             carry2=1,carry2         }
 928 { .mfi;         xma.lu  f97=f39,f125,f97
 929         cmp.ltu         p7,p0=r22,carry1        };;
 930 { .mfi; getf.sig        r29=f65
 931                 xma.hu  f108=f39,f126,f107
 932 (p7)    add             carry2=1,carry2         }
 933 { .mfi; st8             [r32]=r22,16
 934                 xma.lu  f107=f39,f126,f107      };;
 935 { .mfi; getf.sig        r30=f56
 936                 xma.hu  f118=f39,f127,f117      }
 937 { .mfi;         xma.lu  f117=f39,f127,f117      };;//
 938 //-------------------------------------------------//
 939 // Leaving muliplier's heaven... Quite a ride, huh?
 940
 941 { .mii; getf.sig        r31=f47
 942         add             r25=r25,r24
 943         mov             carry1=0                };;
 944 { .mii;         getf.sig        r16=f111
 945         cmp.ltu         p6,p0=r25,r24
 946         add             r26=r26,r25             };;
 947 { .mfb;         getf.sig        r17=f102        }
 948 { .mii;
 949 (p6)    add             carry1=1,carry1
 950         cmp.ltu         p6,p0=r26,r25
 951         add             r27=r27,r26             };;
 952 { .mfb; nop.m   0x0                             }
 953 { .mii;
 954 (p6)    add             carry1=1,carry1
 955         cmp.ltu         p6,p0=r27,r26
 956         add             r28=r28,r27             };;
 957 { .mii;         getf.sig        r18=f93
 958                 add             r17=r17,r16
 959                 mov             carry3=0        }
 960 { .mii;
 961 (p6)    add             carry1=1,carry1
 962         cmp.ltu         p6,p0=r28,r27
 963         add             r29=r29,r28             };;
 964 { .mii;         getf.sig        r19=f84
 965                 cmp.ltu         p7,p0=r17,r16   }
 966 { .mii;
 967 (p6)    add             carry1=1,carry1
 968         cmp.ltu         p6,p0=r29,r28
 969         add             r30=r30,r29             };;
 970 { .mii;         getf.sig        r20=f75
 971                 add             r18=r18,r17     }
 972 { .mii;
 973 (p6)    add             carry1=1,carry1
 974         cmp.ltu         p6,p0=r30,r29
 975         add             r31=r31,r30             };;
 976 { .mfb;         getf.sig        r21=f66         }
 977 { .mii; (p7)    add             carry3=1,carry3
 978                 cmp.ltu         p7,p0=r18,r17
 979                 add             r19=r19,r18     }
 980 { .mfb; nop.m   0x0                             }
 981 { .mii;
 982 (p6)    add             carry1=1,carry1
 983         cmp.ltu         p6,p0=r31,r30
 984         add             r31=r31,carry2          };;
 985 { .mfb;         getf.sig        r22=f57         }
 986 { .mii; (p7)    add             carry3=1,carry3
 987                 cmp.ltu         p7,p0=r19,r18
 988                 add             r20=r20,r19     }
 989 { .mfb; nop.m   0x0                             }
 990 { .mii;
 991 (p6)    add             carry1=1,carry1
 992         cmp.ltu         p6,p0=r31,carry2        };;
 993 { .mfb;         getf.sig        r23=f48         }
 994 { .mii; (p7)    add             carry3=1,carry3
 995                 cmp.ltu         p7,p0=r20,r19
 996                 add             r21=r21,r20     }
 997 { .mii;
 998 (p6)    add             carry1=1,carry1         }
 999 { .mfb; st8             [r33]=r31,16            };;
1000
1001 { .mfb; getf.sig        r24=f112                }
1002 { .mii; (p7)    add             carry3=1,carry3
1003                 cmp.ltu         p7,p0=r21,r20
1004                 add             r22=r22,r21     };;
1005 { .mfb; getf.sig        r25=f103                }
1006 { .mii; (p7)    add             carry3=1,carry3
1007                 cmp.ltu         p7,p0=r22,r21
1008                 add             r23=r23,r22     };;
1009 { .mfb; getf.sig        r26=f94                 }
1010 { .mii; (p7)    add             carry3=1,carry3
1011                 cmp.ltu         p7,p0=r23,r22
1012                 add             r23=r23,carry1  };;
1013 { .mfb; getf.sig        r27=f85                 }
1014 { .mii; (p7)    add             carry3=1,carry3
1015                 cmp.ltu         p7,p8=r23,carry1};;
1016 { .mii; getf.sig        r28=f76
1017         add             r25=r25,r24
1018         mov             carry1=0                }
1019 { .mii;         st8             [r32]=r23,16
1020         (p7)    add             carry2=1,carry3
1021         (p8)    add             carry2=0,carry3 };;
1022
1023 { .mfb; nop.m   0x0                             }
1024 { .mii; getf.sig        r29=f67
1025         cmp.ltu         p6,p0=r25,r24
1026         add             r26=r26,r25             };;
1027 { .mfb; getf.sig        r30=f58                 }
1028 { .mii;
1029 (p6)    add             carry1=1,carry1
1030         cmp.ltu         p6,p0=r26,r25
1031         add             r27=r27,r26             };;
1032 { .mfb;         getf.sig        r16=f113        }
1033 { .mii;
1034 (p6)    add             carry1=1,carry1
1035         cmp.ltu         p6,p0=r27,r26
1036         add             r28=r28,r27             };;
1037 { .mfb;         getf.sig        r17=f104        }
1038 { .mii;
1039 (p6)    add             carry1=1,carry1
1040         cmp.ltu         p6,p0=r28,r27
1041         add             r29=r29,r28             };;
1042 { .mfb;         getf.sig        r18=f95         }
1043 { .mii;
1044 (p6)    add             carry1=1,carry1
1045         cmp.ltu         p6,p0=r29,r28
1046         add             r30=r30,r29             };;
1047 { .mii;         getf.sig        r19=f86
1048                 add             r17=r17,r16
1049                 mov             carry3=0        }
1050 { .mii;
1051 (p6)    add             carry1=1,carry1
1052         cmp.ltu         p6,p0=r30,r29
1053         add             r30=r30,carry2          };;
1054 { .mii;         getf.sig        r20=f77
1055                 cmp.ltu         p7,p0=r17,r16
1056                 add             r18=r18,r17     }
1057 { .mii;
1058 (p6)    add             carry1=1,carry1
1059         cmp.ltu         p6,p0=r30,carry2        };;
1060 { .mfb;         getf.sig        r21=f68         }
1061 { .mii; st8             [r33]=r30,16
1062 (p6)    add             carry1=1,carry1         };;
1063
1064 { .mfb; getf.sig        r24=f114                }
1065 { .mii; (p7)    add             carry3=1,carry3
1066                 cmp.ltu         p7,p0=r18,r17
1067                 add             r19=r19,r18     };;
1068 { .mfb; getf.sig        r25=f105                }
1069 { .mii; (p7)    add             carry3=1,carry3
1070                 cmp.ltu         p7,p0=r19,r18
1071                 add             r20=r20,r19     };;
1072 { .mfb; getf.sig        r26=f96                 }
1073 { .mii; (p7)    add             carry3=1,carry3
1074                 cmp.ltu         p7,p0=r20,r19
1075                 add             r21=r21,r20     };;
1076 { .mfb; getf.sig        r27=f87                 }
1077 { .mii; (p7)    add             carry3=1,carry3
1078                 cmp.ltu         p7,p0=r21,r20
1079                 add             r21=r21,carry1  };;
1080 { .mib; getf.sig        r28=f78
1081         add             r25=r25,r24             }
1082 { .mib; (p7)    add             carry3=1,carry3
1083                 cmp.ltu         p7,p8=r21,carry1};;
1084 { .mii;         st8             [r32]=r21,16
1085         (p7)    add             carry2=1,carry3
1086         (p8)    add             carry2=0,carry3 }
1087
1088 { .mii; mov             carry1=0
1089         cmp.ltu         p6,p0=r25,r24
1090         add             r26=r26,r25             };;
1091 { .mfb;         getf.sig        r16=f115        }
1092 { .mii;
1093 (p6)    add             carry1=1,carry1
1094         cmp.ltu         p6,p0=r26,r25
1095         add             r27=r27,r26             };;
1096 { .mfb;         getf.sig        r17=f106        }
1097 { .mii;
1098 (p6)    add             carry1=1,carry1
1099         cmp.ltu         p6,p0=r27,r26
1100         add             r28=r28,r27             };;
1101 { .mfb;         getf.sig        r18=f97         }
1102 { .mii;
1103 (p6)    add             carry1=1,carry1
1104         cmp.ltu         p6,p0=r28,r27
1105         add             r28=r28,carry2          };;
1106 { .mib;         getf.sig        r19=f88
1107                 add             r17=r17,r16     }
1108 { .mib;
1109 (p6)    add             carry1=1,carry1
1110         cmp.ltu         p6,p0=r28,carry2        };;
1111 { .mii; st8             [r33]=r28,16
1112 (p6)    add             carry1=1,carry1         }
1113
1114 { .mii;         mov             carry2=0
1115                 cmp.ltu         p7,p0=r17,r16
1116                 add             r18=r18,r17     };;
1117 { .mfb; getf.sig        r24=f116                }
1118 { .mii; (p7)    add             carry2=1,carry2
1119                 cmp.ltu         p7,p0=r18,r17
1120                 add             r19=r19,r18     };;
1121 { .mfb; getf.sig        r25=f107                }
1122 { .mii; (p7)    add             carry2=1,carry2
1123                 cmp.ltu         p7,p0=r19,r18
1124                 add             r19=r19,carry1  };;
1125 { .mfb; getf.sig        r26=f98                 }
1126 { .mii; (p7)    add             carry2=1,carry2
1127                 cmp.ltu         p7,p0=r19,carry1};;
1128 { .mii;         st8             [r32]=r19,16
1129         (p7)    add             carry2=1,carry2 }
1130
1131 { .mfb; add             r25=r25,r24             };;
1132
1133 { .mfb;         getf.sig        r16=f117        }
1134 { .mii; mov             carry1=0
1135         cmp.ltu         p6,p0=r25,r24
1136         add             r26=r26,r25             };;
1137 { .mfb;         getf.sig        r17=f108        }
1138 { .mii;
1139 (p6)    add             carry1=1,carry1
1140         cmp.ltu         p6,p0=r26,r25
1141         add             r26=r26,carry2          };;
1142 { .mfb; nop.m   0x0                             }
1143 { .mii;
1144 (p6)    add             carry1=1,carry1
1145         cmp.ltu         p6,p0=r26,carry2        };;
1146 { .mii; st8             [r33]=r26,16
1147 (p6)    add             carry1=1,carry1         }
1148
1149 { .mfb;         add             r17=r17,r16     };;
1150 { .mfb; getf.sig        r24=f118                }
1151 { .mii;         mov             carry2=0
1152                 cmp.ltu         p7,p0=r17,r16
1153                 add             r17=r17,carry1  };;
1154 { .mii; (p7)    add             carry2=1,carry2
1155                 cmp.ltu         p7,p0=r17,carry1};;
1156 { .mii;         st8             [r32]=r17
1157         (p7)    add             carry2=1,carry2 };;
1158 { .mfb; add             r24=r24,carry2          };;
1159 { .mib; st8             [r33]=r24               }
1160
1161 { .mib; rum             1<<5            // clear um.mfh
1162         br.ret.sptk.many        b0      };;
1163 .endp   bn_mul_comba8#
1164 #undef  carry3
1165 #undef  carry2
1166 #undef  carry1
1167 #endif
1168
1169 #if 1
1170 // It's possible to make it faster (see comment to bn_sqr_comba8), but
1171 // I reckon it doesn't worth the effort. Basically because the routine
1172 // (actually both of them) practically never called... So I just play
1173 // same trick as with bn_sqr_comba8.
1174 //
1175 // void bn_sqr_comba4(BN_ULONG *r, BN_ULONG *a)
1176 //
1177 .global bn_sqr_comba4#
1178 .proc   bn_sqr_comba4#
1179 .align  64
1180 bn_sqr_comba4:
1181         .prologue
1182         .save   ar.pfs,r2
1183 #if defined(_HPUX_SOURCE) && !defined(_LP64)
1184 { .mii; alloc   r2=ar.pfs,2,1,0,0
1185         addp4   r32=0,r32
1186         addp4   r33=0,r33               };;
1187 { .mii;
1188 #else
1189 { .mii; alloc   r2=ar.pfs,2,1,0,0
1190 #endif
1191         mov     r34=r33
1192         add     r14=8,r33               };;
1193         .body
1194 { .mii; add     r17=8,r34
1195         add     r15=16,r33
1196         add     r18=16,r34              }
1197 { .mfb; add     r16=24,r33
1198         br      .L_cheat_entry_point4   };;
1199 .endp   bn_sqr_comba4#
1200 #endif
1201
1202 #if 1
1203 // Runs in ~115 cycles and ~4.5 times faster than C. Well, whatever...
1204 //
1205 // void bn_mul_comba4(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
1206 //
1207 #define carry1  r14
1208 #define carry2  r15
1209 .global bn_mul_comba4#
1210 .proc   bn_mul_comba4#
1211 .align  64
1212 bn_mul_comba4:
1213         .prologue
1214         .save   ar.pfs,r2
1215 #if defined(_HPUX_SOURCE) && !defined(_LP64)
1216 { .mii; alloc   r2=ar.pfs,3,0,0,0
1217         addp4   r33=0,r33
1218         addp4   r34=0,r34               };;
1219 { .mii; addp4   r32=0,r32
1220 #else
1221 { .mii; alloc   r2=ar.pfs,3,0,0,0
1222 #endif
1223         add     r14=8,r33
1224         add     r17=8,r34               }
1225         .body
1226 { .mii; add     r15=16,r33
1227         add     r18=16,r34
1228         add     r16=24,r33              };;
1229 .L_cheat_entry_point4:
1230 { .mmi; add     r19=24,r34
1231
1232         ldf8    f32=[r33]               }
1233
1234 { .mmi; ldf8    f120=[r34]
1235         ldf8    f121=[r17]              };;
1236 { .mmi; ldf8    f122=[r18]
1237         ldf8    f123=[r19]              }
1238
1239 { .mmi; ldf8    f33=[r14]
1240         ldf8    f34=[r15]               }
1241 { .mfi; ldf8    f35=[r16]
1242
1243                 xma.hu  f41=f32,f120,f0         }
1244 { .mfi;         xma.lu  f40=f32,f120,f0         };;
1245 { .mfi;         xma.hu  f51=f32,f121,f0         }
1246 { .mfi;         xma.lu  f50=f32,f121,f0         };;
1247 { .mfi;         xma.hu  f61=f32,f122,f0         }
1248 { .mfi;         xma.lu  f60=f32,f122,f0         };;
1249 { .mfi;         xma.hu  f71=f32,f123,f0         }
1250 { .mfi;         xma.lu  f70=f32,f123,f0         };;//
1251 // Major stall takes place here, and 3 more places below. Result from
1252 // first xma is not available for another 3 ticks.
1253 { .mfi; getf.sig        r16=f40
1254                 xma.hu  f42=f33,f120,f41
1255         add             r33=8,r32               }
1256 { .mfi;         xma.lu  f41=f33,f120,f41        };;
1257 { .mfi; getf.sig        r24=f50
1258                 xma.hu  f52=f33,f121,f51        }
1259 { .mfi;         xma.lu  f51=f33,f121,f51        };;
1260 { .mfi; st8             [r32]=r16,16
1261                 xma.hu  f62=f33,f122,f61        }
1262 { .mfi;         xma.lu  f61=f33,f122,f61        };;
1263 { .mfi;         xma.hu  f72=f33,f123,f71        }
1264 { .mfi;         xma.lu  f71=f33,f123,f71        };;//
1265 //-------------------------------------------------//
1266 { .mfi; getf.sig        r25=f41
1267                 xma.hu  f43=f34,f120,f42        }
1268 { .mfi;         xma.lu  f42=f34,f120,f42        };;
1269 { .mfi; getf.sig        r16=f60
1270                 xma.hu  f53=f34,f121,f52        }
1271 { .mfi;         xma.lu  f52=f34,f121,f52        };;
1272 { .mfi; getf.sig        r17=f51
1273                 xma.hu  f63=f34,f122,f62
1274         add             r25=r25,r24             }
1275 { .mfi; mov             carry1=0
1276                 xma.lu  f62=f34,f122,f62        };;
1277 { .mfi; st8             [r33]=r25,16
1278                 xma.hu  f73=f34,f123,f72
1279         cmp.ltu         p6,p0=r25,r24           }
1280 { .mfi;         xma.lu  f72=f34,f123,f72        };;//
1281 //-------------------------------------------------//
1282 { .mfi; getf.sig        r18=f42
1283                 xma.hu  f44=f35,f120,f43
1284 (p6)    add             carry1=1,carry1         }
1285 { .mfi; add             r17=r17,r16
1286                 xma.lu  f43=f35,f120,f43
1287         mov             carry2=0                };;
1288 { .mfi; getf.sig        r24=f70
1289                 xma.hu  f54=f35,f121,f53
1290         cmp.ltu         p7,p0=r17,r16           }
1291 { .mfi;         xma.lu  f53=f35,f121,f53        };;
1292 { .mfi; getf.sig        r25=f61
1293                 xma.hu  f64=f35,f122,f63
1294         add             r18=r18,r17             }
1295 { .mfi;         xma.lu  f63=f35,f122,f63
1296 (p7)    add             carry2=1,carry2         };;
1297 { .mfi; getf.sig        r26=f52
1298                 xma.hu  f74=f35,f123,f73
1299         cmp.ltu         p7,p0=r18,r17           }
1300 { .mfi;         xma.lu  f73=f35,f123,f73
1301         add             r18=r18,carry1          };;
1302 //-------------------------------------------------//
1303 { .mii; st8             [r32]=r18,16
1304 (p7)    add             carry2=1,carry2
1305         cmp.ltu         p7,p0=r18,carry1        };;
1306
1307 { .mfi; getf.sig        r27=f43 // last major stall
1308 (p7)    add             carry2=1,carry2         };;
1309 { .mii;         getf.sig        r16=f71
1310         add             r25=r25,r24
1311         mov             carry1=0                };;
1312 { .mii;         getf.sig        r17=f62
1313         cmp.ltu         p6,p0=r25,r24
1314         add             r26=r26,r25             };;
1315 { .mii;
1316 (p6)    add             carry1=1,carry1
1317         cmp.ltu         p6,p0=r26,r25
1318         add             r27=r27,r26             };;
1319 { .mii;
1320 (p6)    add             carry1=1,carry1
1321         cmp.ltu         p6,p0=r27,r26
1322         add             r27=r27,carry2          };;
1323 { .mii;         getf.sig        r18=f53
1324 (p6)    add             carry1=1,carry1
1325         cmp.ltu         p6,p0=r27,carry2        };;
1326 { .mfi; st8             [r33]=r27,16
1327 (p6)    add             carry1=1,carry1         }
1328
1329 { .mii;         getf.sig        r19=f44
1330                 add             r17=r17,r16
1331                 mov             carry2=0        };;
1332 { .mii; getf.sig        r24=f72
1333                 cmp.ltu         p7,p0=r17,r16
1334                 add             r18=r18,r17     };;
1335 { .mii; (p7)    add             carry2=1,carry2
1336                 cmp.ltu         p7,p0=r18,r17
1337                 add             r19=r19,r18     };;
1338 { .mii; (p7)    add             carry2=1,carry2
1339                 cmp.ltu         p7,p0=r19,r18
1340                 add             r19=r19,carry1  };;
1341 { .mii; getf.sig        r25=f63
1342         (p7)    add             carry2=1,carry2
1343                 cmp.ltu         p7,p0=r19,carry1};;
1344 { .mii;         st8             [r32]=r19,16
1345         (p7)    add             carry2=1,carry2 }
1346
1347 { .mii; getf.sig        r26=f54
1348         add             r25=r25,r24
1349         mov             carry1=0                };;
1350 { .mii;         getf.sig        r16=f73
1351         cmp.ltu         p6,p0=r25,r24
1352         add             r26=r26,r25             };;
1353 { .mii;
1354 (p6)    add             carry1=1,carry1
1355         cmp.ltu         p6,p0=r26,r25
1356         add             r26=r26,carry2          };;
1357 { .mii;         getf.sig        r17=f64
1358 (p6)    add             carry1=1,carry1
1359         cmp.ltu         p6,p0=r26,carry2        };;
1360 { .mii; st8             [r33]=r26,16
1361 (p6)    add             carry1=1,carry1         }
1362
1363 { .mii; getf.sig        r24=f74
1364                 add             r17=r17,r16
1365                 mov             carry2=0        };;
1366 { .mii;         cmp.ltu         p7,p0=r17,r16
1367                 add             r17=r17,carry1  };;
1368
1369 { .mii; (p7)    add             carry2=1,carry2
1370                 cmp.ltu         p7,p0=r17,carry1};;
1371 { .mii;         st8             [r32]=r17,16
1372         (p7)    add             carry2=1,carry2 };;
1373
1374 { .mii; add             r24=r24,carry2          };;
1375 { .mii; st8             [r33]=r24               }
1376
1377 { .mib; rum             1<<5            // clear um.mfh
1378         br.ret.sptk.many        b0      };;
1379 .endp   bn_mul_comba4#
1380 #undef  carry2
1381 #undef  carry1
1382 #endif
1383
1384 #if 1
1385 //
1386 // BN_ULONG bn_div_words(BN_ULONG h, BN_ULONG l, BN_ULONG d)
1387 //
1388 // In the nutshell it's a port of my MIPS III/IV implementation.
1389 //
1390 #define AT      r14
1391 #define H       r16
1392 #define HH      r20
1393 #define L       r17
1394 #define D       r18
1395 #define DH      r22
1396 #define I       r21
1397
1398 #if 0
1399 // Some preprocessors (most notably HP-UX) appear to be allergic to
1400 // macros enclosed to parenthesis [as these three were].
1401 #define cont    p16
1402 #define break   p0      // p20
1403 #define equ     p24
1404 #else
1405 cont=p16
1406 break=p0
1407 equ=p24
1408 #endif
1409
1410 .global abort#
1411 .global bn_div_words#
1412 .proc   bn_div_words#
1413 .align  64
1414 bn_div_words:
1415         .prologue
1416         .save   ar.pfs,r2
1417 { .mii; alloc           r2=ar.pfs,3,5,0,8
1418         .save   b0,r3
1419         mov             r3=b0
1420         .save   pr,r10
1421         mov             r10=pr          };;
1422 { .mmb; cmp.eq          p6,p0=r34,r0
1423         mov             r8=-1
1424 (p6)    br.ret.spnt.many        b0      };;
1425
1426         .body
1427 { .mii; mov             H=r32           // save h
1428         mov             ar.ec=0         // don't rotate at exit
1429         mov             pr.rot=0        }
1430 { .mii; mov             L=r33           // save l
1431         mov             r36=r0          };;
1432
1433 .L_divw_shift:  // -vv- note signed comparison
1434 { .mfi; (p0)    cmp.lt          p16,p0=r0,r34   // d
1435         (p0)    shladd          r33=r34,1,r0    }
1436 { .mfb; (p0)    add             r35=1,r36
1437         (p0)    nop.f           0x0
1438 (p16)   br.wtop.dpnt            .L_divw_shift   };;
1439
1440 { .mii; mov             D=r34
1441         shr.u           DH=r34,32
1442         sub             r35=64,r36              };;
1443 { .mii; setf.sig        f7=DH
1444         shr.u           AT=H,r35
1445         mov             I=r36                   };;
1446 { .mib; cmp.ne          p6,p0=r0,AT
1447         shl             H=H,r36
1448 (p6)    br.call.spnt.clr        b0=abort        };;     // overflow, die...
1449
1450 { .mfi; fcvt.xuf.s1     f7=f7
1451         shr.u           AT=L,r35                };;
1452 { .mii; shl             L=L,r36
1453         or              H=H,AT                  };;
1454
1455 { .mii; nop.m           0x0
1456         cmp.leu         p6,p0=D,H;;
1457 (p6)    sub             H=H,D                   }
1458
1459 { .mlx; setf.sig        f14=D
1460         movl            AT=0xffffffff           };;
1461 ///////////////////////////////////////////////////////////
1462 { .mii; setf.sig        f6=H
1463         shr.u           HH=H,32;;
1464         cmp.eq          p6,p7=HH,DH             };;
1465 { .mfb;
1466 (p6)    setf.sig        f8=AT
1467 (p7)    fcvt.xuf.s1     f6=f6
1468 (p7)    br.call.sptk    b6=.L_udiv64_32_b6      };;
1469
1470 { .mfi; getf.sig        r33=f8                          // q
1471         xmpy.lu         f9=f8,f14               }
1472 { .mfi; xmpy.hu         f10=f8,f14
1473         shrp            H=H,L,32                };;
1474
1475 { .mmi; getf.sig        r35=f9                          // tl
1476         getf.sig        r31=f10                 };;     // th
1477
1478 .L_divw_1st_iter:
1479 { .mii; (p0)    add             r32=-1,r33
1480         (p0)    cmp.eq          equ,cont=HH,r31         };;
1481 { .mii; (p0)    cmp.ltu         p8,p0=r35,D
1482         (p0)    sub             r34=r35,D
1483         (equ)   cmp.leu         break,cont=r35,H        };;
1484 { .mib; (cont)  cmp.leu         cont,break=HH,r31
1485         (p8)    add             r31=-1,r31
1486 (cont)  br.wtop.spnt            .L_divw_1st_iter        };;
1487 ///////////////////////////////////////////////////////////
1488 { .mii; sub             H=H,r35
1489         shl             r8=r33,32
1490         shl             L=L,32                  };;
1491 ///////////////////////////////////////////////////////////
1492 { .mii; setf.sig        f6=H
1493         shr.u           HH=H,32;;
1494         cmp.eq          p6,p7=HH,DH             };;
1495 { .mfb;
1496 (p6)    setf.sig        f8=AT
1497 (p7)    fcvt.xuf.s1     f6=f6
1498 (p7)    br.call.sptk    b6=.L_udiv64_32_b6      };;
1499
1500 { .mfi; getf.sig        r33=f8                          // q
1501         xmpy.lu         f9=f8,f14               }
1502 { .mfi; xmpy.hu         f10=f8,f14
1503         shrp            H=H,L,32                };;
1504
1505 { .mmi; getf.sig        r35=f9                          // tl
1506         getf.sig        r31=f10                 };;     // th
1507
1508 .L_divw_2nd_iter:
1509 { .mii; (p0)    add             r32=-1,r33
1510         (p0)    cmp.eq          equ,cont=HH,r31         };;
1511 { .mii; (p0)    cmp.ltu         p8,p0=r35,D
1512         (p0)    sub             r34=r35,D
1513         (equ)   cmp.leu         break,cont=r35,H        };;
1514 { .mib; (cont)  cmp.leu         cont,break=HH,r31
1515         (p8)    add             r31=-1,r31
1516 (cont)  br.wtop.spnt            .L_divw_2nd_iter        };;
1517 ///////////////////////////////////////////////////////////
1518 { .mii; sub     H=H,r35
1519         or      r8=r8,r33
1520         mov     ar.pfs=r2               };;
1521 { .mii; shr.u   r9=H,I                  // remainder if anybody wants it
1522         mov     pr=r10,0x1ffff          }
1523 { .mfb; br.ret.sptk.many        b0      };;
1524
1525 // Unsigned 64 by 32 (well, by 64 for the moment) bit integer division
1526 // procedure.
1527 //
1528 // inputs:      f6 = (double)a, f7 = (double)b
1529 // output:      f8 = (int)(a/b)
1530 // clobbered:   f8,f9,f10,f11,pred
1531 pred=p15
1532 // One can argue that this snippet is copyrighted to Intel
1533 // Corporation, as it's essentially identical to one of those
1534 // found in "Divide, Square Root and Remainder" section at
1535 // http://www.intel.com/software/products/opensource/libraries/num.htm.
1536 // Yes, I admit that the referred code was used as template,
1537 // but after I realized that there hardly is any other instruction
1538 // sequence which would perform this operation. I mean I figure that
1539 // any independent attempt to implement high-performance division
1540 // will result in code virtually identical to the Intel code. It
1541 // should be noted though that below division kernel is 1 cycle
1542 // faster than Intel one (note commented splits:-), not to mention
1543 // original prologue (rather lack of one) and epilogue.
1544 .align  32
1545 .skip   16
1546 .L_udiv64_32_b6:
1547         frcpa.s1        f8,pred=f6,f7;;         // [0]  y0 = 1 / b
1548
1549 (pred)  fnma.s1         f9=f7,f8,f1             // [5]  e0 = 1 - b * y0
1550 (pred)  fmpy.s1         f10=f6,f8;;             // [5]  q0 = a * y0
1551 (pred)  fmpy.s1         f11=f9,f9               // [10] e1 = e0 * e0
1552 (pred)  fma.s1          f10=f9,f10,f10;;        // [10] q1 = q0 + e0 * q0
1553 (pred)  fma.s1          f8=f9,f8,f8     //;;    // [15] y1 = y0 + e0 * y0
1554 (pred)  fma.s1          f9=f11,f10,f10;;        // [15] q2 = q1 + e1 * q1
1555 (pred)  fma.s1          f8=f11,f8,f8    //;;    // [20] y2 = y1 + e1 * y1
1556 (pred)  fnma.s1         f10=f7,f9,f6;;          // [20] r2 = a - b * q2
1557 (pred)  fma.s1          f8=f10,f8,f9;;          // [25] q3 = q2 + r2 * y2
1558
1559         fcvt.fxu.trunc.s1       f8=f8           // [30] q = trunc(q3)
1560         br.ret.sptk.many        b6;;
1561 .endp   bn_div_words#
1562 #endif