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