decoder.isa revision 12692:1eaaa1d75080 
1// -*- mode:c++ -*-
2
3// Copyright (c) 2009 The University of Edinburgh
4// All rights reserved.
5//
6// Redistribution and use in source and binary forms, with or without
7// modification, are permitted provided that the following conditions are
8// met: redistributions of source code must retain the above copyright
9// notice, this list of conditions and the following disclaimer;
10// redistributions in binary form must reproduce the above copyright
11// notice, this list of conditions and the following disclaimer in the
12// documentation and/or other materials provided with the distribution;
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15// this software without specific prior written permission.
16//
17// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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19// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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23// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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27// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28//
29// Authors: Timothy M. Jones
30
31////////////////////////////////////////////////////////////////////
32//
33// The actual Power ISA decoder
34// ------------------------------
35//
36// I've used the Power ISA Book I v2.06 for instruction formats,
37// opcode numbers, register names, etc.
38//
39decode OPCODE default Unknown::unknown() {
40
41    format IntImmOp {
42        10: cmpli({{
43            Xer xer = XER;
44            uint32_t cr = makeCRField(Ra, (uint32_t)uimm, xer.so);
45            CR = insertCRField(CR, BF, cr);
46            }});
47        11: cmpi({{
48            Xer xer = XER;
49            uint32_t cr = makeCRField(Ra_sw, (int32_t)imm, xer.so);
50            CR = insertCRField(CR, BF, cr);
51            }});
52    }
53
54    // Some instructions use bits 21 - 30, others 22 - 30. We have to use
55    // the larger size to account for all opcodes. For those that use the
56    // smaller value, the OE bit is bit 21. Therefore, we have two versions
57    // of each instruction: 1 with OE set, the other without. For an
58    // example see 'add' and 'addo'.
59    31: decode XO_XO {
60
61        // These instructions can all be reduced to the form
62        // Rt = src1 + src2 [+ CA], therefore we just give src1 and src2
63        // (and, if necessary, CA) definitions and let the python script
64        // deal with setting things up correctly. We also give flags to
65        // say which control registers to set.
66        format IntSumOp {
67            266: add({{ Ra }}, {{ Rb }});
68            40: subf({{ ~Ra }}, {{ Rb }}, {{ 1 }});
69            10: addc({{ Ra }}, {{ Rb }},
70                     computeCA = true);
71            8: subfc({{ ~Ra }}, {{ Rb }}, {{ 1 }},
72                     true);
73            104: neg({{ ~Ra }}, {{ 1 }});
74            138: adde({{ Ra }}, {{ Rb }}, {{ xer.ca }},
75                      true);
76            234: addme({{ Ra }}, {{ (uint32_t)-1 }}, {{ xer.ca }},
77                       true);
78            136: subfe({{ ~Ra }}, {{ Rb }}, {{ xer.ca }},
79                       true);
80            232: subfme({{ ~Ra }}, {{ (uint32_t)-1 }}, {{ xer.ca }},
81                        true);
82            202: addze({{ Ra }}, {{ xer.ca }},
83                       computeCA = true);
84            200: subfze({{ ~Ra }}, {{ xer.ca }},
85                        computeCA = true);
86        }
87
88        // Arithmetic instructions all use source registers Ra and Rb,
89        // with destination register Rt.
90        format IntArithOp {
91            75: mulhw({{ int64_t prod = Ra_sq * Rb_sq; Rt = prod >> 32; }});
92            11: mulhwu({{ uint64_t prod = Ra_uq * Rb_uq; Rt = prod >> 32; }});
93            235: mullw({{ int64_t prod = Ra_sq * Rb_sq; Rt = prod; }});
94            747: mullwo({{ int64_t src1 = Ra_sq; int64_t src2 = Rb; int64_t prod = src1 * src2; Rt = prod; }},
95                        true);
96
97            491: divw({{
98                int32_t src1 = Ra_sw;
99                int32_t src2 = Rb_sw;
100                if ((src1 != 0x80000000 || src2 != 0xffffffff)
101                    && src2 != 0) {
102                    Rt = src1 / src2;
103                } else {
104                    Rt = 0;
105                }
106            }});
107
108            1003: divwo({{
109                int32_t src1 = Ra_sw;
110                int32_t src2 = Rb_sw;
111                if ((src1 != 0x80000000 || src2 != 0xffffffff)
112                    && src2 != 0) {
113                    Rt = src1 / src2;
114                } else {
115                    Rt = 0;
116                    divSetOV = true;
117                }
118            }},
119            true);
120
121            459: divwu({{
122                uint32_t src1 = Ra_sw;
123                uint32_t src2 = Rb_sw;
124                if (src2 != 0) {
125                    Rt = src1 / src2;
126                } else {
127                    Rt = 0;
128                }
129            }});
130
131            971: divwuo({{
132              uint32_t src1 = Ra_sw;
133              uint32_t src2 = Rb_sw;
134              if (src2 != 0) {
135                  Rt = src1 / src2;
136              } else {
137                  Rt = 0;
138                  divSetOV = true;
139              }
140            }},
141            true);
142        }
143
144        // Integer logic instructions use source registers Rs and Rb,
145        // with destination register Ra.
146        format IntLogicOp {
147            28: and({{ Ra = Rs & Rb; }});
148            316: xor({{ Ra = Rs ^ Rb; }});
149            476: nand({{ Ra = ~(Rs & Rb); }});
150            444: or({{ Ra = Rs | Rb; }});
151            124: nor({{ Ra = ~(Rs | Rb); }});
152            60: andc({{ Ra = Rs & ~Rb; }});
153            954: extsb({{ Ra = sext<8>(Rs); }});
154            284: eqv({{ Ra = ~(Rs ^ Rb); }});
155            412: orc({{ Ra = Rs | ~Rb; }});
156            922: extsh({{ Ra = sext<16>(Rs); }});
157            26: cntlzw({{ Ra = Rs == 0 ? 32 : 31 - findMsbSet(Rs); }});
158            508: cmpb({{
159                uint32_t val = 0;
160                for (int n = 0; n < 32; n += 8) {
161                    if(bits(Rs, n+7, n) == bits(Rb, n+7, n)) {
162                        val = insertBits(val, n+7, n, 0xff);
163                    }
164                }
165                Ra = val;
166            }});
167
168            24: slw({{
169                if (Rb & 0x20) {
170                    Ra = 0;
171                } else {
172                    Ra = Rs << (Rb & 0x1f);
173                }
174            }});
175
176            536: srw({{
177                if (Rb & 0x20) {
178                    Ra = 0;
179                } else  {
180                    Ra = Rs >> (Rb & 0x1f);
181                }
182            }});
183
184            792: sraw({{
185                bool shiftSetCA = false;
186                int32_t s = Rs;
187                if (Rb == 0) {
188                    Ra = Rs;
189                    shiftSetCA = true;
190                } else if (Rb & 0x20) {
191                    if (s < 0) {
192                        Ra = (uint32_t)-1;
193                        if (s & 0x7fffffff) {
194                            shiftSetCA = true;
195                        } else {
196                            shiftSetCA = false;
197                        }
198                    } else {
199                        Ra = 0;
200                        shiftSetCA = false;
201                    }
202                } else {
203                    Ra = s >> (Rb & 0x1f);
204                    if (s < 0 && (s << (32 - (Rb & 0x1f))) != 0) {
205                        shiftSetCA = true;
206                    } else {
207                        shiftSetCA = false;
208                    }
209                }
210                Xer xer1 = XER;
211                if (shiftSetCA) {
212                    xer1.ca = 1;
213                } else {
214                    xer1.ca = 0;
215                }
216                XER = xer1;
217            }});
218        }
219
220        // Integer logic instructions with a shift value.
221        format IntShiftOp {
222            824: srawi({{
223                bool shiftSetCA = false;
224                if (sh == 0) {
225                    Ra = Rs;
226                    shiftSetCA = false;
227                } else {
228                    int32_t s = Rs;
229                    Ra = s >> sh;
230                    if (s < 0 && (s << (32 - sh)) != 0) {
231                        shiftSetCA = true;
232                    } else {
233                        shiftSetCA = false;
234                    }
235                }
236                Xer xer1 = XER;
237                if (shiftSetCA) {
238                    xer1.ca = 1;
239                } else {
240                    xer1.ca = 0;
241                }
242                XER = xer1;
243            }});
244        }
245
246        // Generic integer format instructions.
247        format IntOp {
248            0: cmp({{
249                Xer xer = XER;
250                uint32_t cr = makeCRField(Ra_sw, Rb_sw, xer.so);
251                CR = insertCRField(CR, BF, cr);
252                }});
253            32: cmpl({{
254                Xer xer = XER;
255                uint32_t cr = makeCRField(Ra, Rb, xer.so);
256                CR = insertCRField(CR, BF, cr);
257                }});
258            144: mtcrf({{
259                uint32_t mask = 0;
260                for (int i = 0; i < 8; ++i) {
261                    if (((FXM >> i) & 0x1) == 0x1) {
262                        mask |= 0xf << (4 * i);
263                    }
264                }
265                CR = (Rs & mask) | (CR & ~mask);
266                }});
267            19: mfcr({{ Rt = CR; }});
268            339: decode SPR {
269                0x20: mfxer({{ Rt = XER; }});
270                0x100: mflr({{ Rt = LR; }});
271                0x120: mfctr({{ Rt = CTR; }});
272            }
273            467: decode SPR {
274                0x20: mtxer({{ XER = Rs; }});
275                0x100: mtlr({{ LR = Rs; }});
276                0x120: mtctr({{ CTR = Rs; }});
277            }
278        }
279
280        // All loads with an index register. The non-update versions
281        // all use the value 0 if Ra == R0, not the value contained in
282        // R0. Others update Ra with the effective address. In all cases,
283        // Ra and Rb are source registers, Rt is the destintation.
284        format LoadIndexOp {
285            87: lbzx({{ Rt = Mem_ub; }});
286            279: lhzx({{ Rt = Mem_uh; }});
287            343: lhax({{ Rt = Mem_sh; }});
288            23: lwzx({{ Rt = Mem; }});
289            341: lwax({{ Rt = Mem_sw; }});
290            20: lwarx({{ Rt = Mem_sw; Rsv = 1; RsvLen = 4; RsvAddr = EA; }});
291            535: lfsx({{ Ft_sf = Mem_sf; }});
292            599: lfdx({{ Ft = Mem_df; }});
293            855: lfiwax({{ Ft_uw = Mem; }});
294        }
295
296        format LoadIndexUpdateOp {
297            119: lbzux({{ Rt = Mem_ub; }});
298            311: lhzux({{ Rt = Mem_uh; }});
299            375: lhaux({{ Rt = Mem_sh; }});
300            55: lwzux({{ Rt = Mem; }});
301            373: lwaux({{ Rt = Mem_sw; }});
302            567: lfsux({{ Ft_sf = Mem_sf; }});
303            631: lfdux({{ Ft = Mem_df; }});
304        }
305
306        format StoreIndexOp {
307            215: stbx({{ Mem_ub = Rs_ub; }});
308            407: sthx({{ Mem_uh = Rs_uh; }});
309            151: stwx({{ Mem = Rs; }});
310            150: stwcx({{
311                bool store_performed = false;
312                Mem = Rs;
313                if (Rsv) {
314                    if (RsvLen == 4) {
315                        if (RsvAddr == EA) {
316                            store_performed = true;
317                        }
318                    }
319                }
320                Xer xer = XER;
321                Cr cr = CR;
322                cr.cr0 = ((store_performed ? 0x2 : 0x0) | xer.so);
323                CR = cr;
324                Rsv = 0;
325            }});
326            663: stfsx({{ Mem_sf = Fs_sf; }});
327            727: stfdx({{ Mem_df = Fs; }});
328            983: stfiwx({{ Mem = Fs_uw; }});
329        }
330
331        format StoreIndexUpdateOp {
332            247: stbux({{ Mem_ub = Rs_ub; }});
333            439: sthux({{ Mem_uh = Rs_uh; }});
334            183: stwux({{ Mem = Rs; }});
335            695: stfsux({{ Mem_sf = Fs_sf; }});
336            759: stfdux({{ Mem_df = Fs; }});
337        }
338
339        // These instructions all provide data cache hints
340        format MiscOp {
341            278: dcbt({{ }});
342            246: dcbtst({{ }});
343            598: sync({{ }}, [ IsMemBarrier ]);
344            854: eieio({{ }}, [ IsMemBarrier ]);
345        }
346    }
347
348    format IntImmArithCheckRaOp {
349        14: addi({{ Rt = Ra + imm; }},
350                 {{ Rt = imm }});
351        15: addis({{ Rt = Ra + (imm << 16); }},
352                  {{ Rt = imm << 16; }});
353    }
354
355    format IntImmArithOp {
356        12: addic({{ uint32_t src = Ra; Rt = src + imm; }},
357                  [computeCA]);
358        13: addic_({{ uint32_t src = Ra; Rt = src + imm; }},
359                   [computeCA, computeCR0]);
360        8: subfic({{ int32_t src = ~Ra; Rt = src + imm + 1; }},
361                  [computeCA]);
362        7: mulli({{
363            int32_t src = Ra_sw;
364            int64_t prod = src * imm;
365            Rt = (uint32_t)prod;
366        }});
367    }
368
369    format IntImmLogicOp {
370        24: ori({{ Ra = Rs | uimm; }});
371        25: oris({{ Ra = Rs | (uimm << 16); }});
372        26: xori({{ Ra = Rs ^ uimm; }});
373        27: xoris({{ Ra = Rs ^ (uimm << 16); }});
374        28: andi_({{ Ra = Rs & uimm; }},
375                  true);
376        29: andis_({{ Ra = Rs & (uimm << 16); }},
377                   true);
378    }
379
380    16: decode AA {
381
382        // Conditionally branch relative to PC based on CR and CTR.
383        format BranchPCRelCondCtr {
384            0: bc({{ NPC = (uint32_t)(PC + disp); }});
385        }
386
387        // Conditionally branch to fixed address based on CR and CTR.
388        format BranchNonPCRelCondCtr {
389            1: bca({{ NPC = targetAddr; }});
390        }
391    }
392
393    18: decode AA {
394
395        // Unconditionally branch relative to PC.
396        format BranchPCRel {
397            0: b({{ NPC = (uint32_t)(PC + disp); }});
398        }
399
400        // Unconditionally branch to fixed address.
401        format BranchNonPCRel {
402            1: ba({{ NPC = targetAddr; }});
403        }
404    }
405
406    19: decode XO_XO {
407
408        // Conditionally branch to address in LR based on CR and CTR.
409        format BranchLrCondCtr {
410           16: bclr({{ NPC = LR & 0xfffffffc; }});
411        }
412
413        // Conditionally branch to address in CTR based on CR.
414        format BranchCtrCond {
415           528: bcctr({{ NPC = CTR & 0xfffffffc; }});
416        }
417
418        // Condition register manipulation instructions.
419        format CondLogicOp {
420            257: crand({{
421                uint32_t crBa = bits(CR, 31 - ba);
422                uint32_t crBb = bits(CR, 31 - bb);
423                CR = insertBits(CR, 31 - bt, crBa & crBb);
424            }});
425            449: cror({{
426                uint32_t crBa = bits(CR, 31 - ba);
427                uint32_t crBb = bits(CR, 31 - bb);
428                CR = insertBits(CR, 31 - bt, crBa | crBb);
429            }});
430            255: crnand({{
431                uint32_t crBa = bits(CR, 31 - ba);
432                uint32_t crBb = bits(CR, 31 - bb);
433                CR = insertBits(CR, 31 - bt, !(crBa & crBb));
434            }});
435            193: crxor({{
436                uint32_t crBa = bits(CR, 31 - ba);
437                uint32_t crBb = bits(CR, 31 - bb);
438                CR = insertBits(CR, 31 - bt, crBa ^ crBb);
439            }});
440            33: crnor({{
441                uint32_t crBa = bits(CR, 31 - ba);
442                uint32_t crBb = bits(CR, 31 - bb);
443                CR = insertBits(CR, 31 - bt, !(crBa | crBb));
444            }});
445            289: creqv({{
446                uint32_t crBa = bits(CR, 31 - ba);
447                uint32_t crBb = bits(CR, 31 - bb);
448                CR = insertBits(CR, 31 - bt, crBa == crBb);
449            }});
450            129: crandc({{
451                uint32_t crBa = bits(CR, 31 - ba);
452                uint32_t crBb = bits(CR, 31 - bb);
453                CR = insertBits(CR, 31 - bt, crBa & !crBb);
454            }});
455            417: crorc({{
456                uint32_t crBa = bits(CR, 31 - ba);
457                uint32_t crBb = bits(CR, 31 - bb);
458                CR = insertBits(CR, 31 - bt, crBa | !crBb);
459            }});
460        }
461        format CondMoveOp {
462            0: mcrf({{
463                uint32_t crBfa = bits(CR, 31 - bfa*4, 28 - bfa*4);
464                CR = insertBits(CR, 31 - bf*4, 28 - bf*4, crBfa);
465            }});
466        }
467        format MiscOp {
468            150: isync({{ }}, [ IsSerializeAfter ]);
469        }
470    }
471
472    format IntRotateOp {
473        21: rlwinm({{ Ra = rotateValue(Rs, sh) & fullMask; }});
474        23: rlwnm({{ Ra = rotateValue(Rs, Rb) & fullMask; }});
475        20: rlwimi({{ Ra = (rotateValue(Rs, sh) & fullMask) | (Ra & ~fullMask); }});
476    }
477
478    format LoadDispOp {
479        34: lbz({{ Rt = Mem_ub; }});
480        40: lhz({{ Rt = Mem_uh; }});
481        42: lha({{ Rt = Mem_sh; }});
482        32: lwz({{ Rt = Mem; }});
483        58: lwa({{ Rt = Mem_sw; }},
484                {{ EA = Ra + (disp & 0xfffffffc); }},
485                {{ EA = disp & 0xfffffffc; }});
486        48: lfs({{ Ft_sf = Mem_sf; }});
487        50: lfd({{ Ft = Mem_df; }});
488    }
489
490    format LoadDispUpdateOp {
491        35: lbzu({{ Rt = Mem_ub; }});
492        41: lhzu({{ Rt = Mem_uh; }});
493        43: lhau({{ Rt = Mem_sh; }});
494        33: lwzu({{ Rt = Mem; }});
495        49: lfsu({{ Ft_sf = Mem_sf; }});
496        51: lfdu({{ Ft = Mem_df; }});
497    }
498
499    format StoreDispOp {
500        38: stb({{ Mem_ub = Rs_ub; }});
501        44: sth({{ Mem_uh = Rs_uh; }});
502        36: stw({{ Mem = Rs; }});
503        52: stfs({{ Mem_sf = Fs_sf; }});
504        54: stfd({{ Mem_df = Fs; }});
505    }
506
507    format StoreDispUpdateOp {
508        39: stbu({{ Mem_ub = Rs_ub; }});
509        45: sthu({{ Mem_uh = Rs_uh; }});
510        37: stwu({{ Mem = Rs; }});
511        53: stfsu({{ Mem_sf = Fs_sf; }});
512        55: stfdu({{ Mem_df = Fs; }});
513    }
514
515    17: IntOp::sc({{ xc->syscall(R0, &fault); }},
516                  [ IsSyscall, IsNonSpeculative, IsSerializeAfter ]);
517
518    format FloatArithOp {
519        59: decode A_XO {
520            21: fadds({{ Ft = Fa + Fb; }});
521            20: fsubs({{ Ft = Fa - Fb; }});
522            25: fmuls({{ Ft = Fa * Fc; }});
523            18: fdivs({{ Ft = Fa / Fb; }});
524            29: fmadds({{ Ft = (Fa * Fc) + Fb; }});
525            28: fmsubs({{ Ft = (Fa * Fc) - Fb; }});
526            31: fnmadds({{ Ft = -((Fa * Fc) + Fb); }});
527            30: fnmsubs({{ Ft = -((Fa * Fc) - Fb); }});
528        }
529    }
530
531    63: decode A_XO {
532        format FloatArithOp {
533            21: fadd({{ Ft = Fa + Fb; }});
534            20: fsub({{ Ft = Fa - Fb; }});
535            25: fmul({{ Ft = Fa * Fc; }});
536            18: fdiv({{ Ft = Fa / Fb; }});
537            29: fmadd({{ Ft = (Fa * Fc) + Fb; }});
538            28: fmsub({{ Ft = (Fa * Fc) - Fb; }});
539            31: fnmadd({{ Ft = -((Fa * Fc) + Fb); }});
540            30: fnmsub({{ Ft = -((Fa * Fc) - Fb); }});
541        }
542
543        default: decode XO_XO {
544            format FloatConvertOp {
545                12: frsp({{ Ft_sf = Fb; }});
546                15: fctiwz({{ Ft_sw = (int32_t)trunc(Fb); }});
547            }
548
549            format FloatOp {
550              0: fcmpu({{
551                  uint32_t c = makeCRField(Fa, Fb);
552                  Fpscr fpscr = FPSCR;
553                  fpscr.fprf.fpcc = c;
554                  FPSCR = fpscr;
555                  CR = insertCRField(CR, BF, c);
556              }});
557            }
558
559            format FloatRCCheckOp {
560                72: fmr({{ Ft = Fb; }});
561                264: fabs({{
562                    Ft_uq = Fb_uq;
563                    Ft_uq = insertBits(Ft_uq, 63, 0); }});
564                136: fnabs({{
565                    Ft_uq = Fb_uq;
566                    Ft_uq = insertBits(Ft_uq, 63, 1); }});
567                40: fneg({{ Ft = -Fb; }});
568                8: fcpsgn({{
569                    Ft_uq = Fb_uq;
570                    Ft_uq = insertBits(Ft_uq, 63, Fa_uq<63:63>);
571                }});
572                583: mffs({{ Ft_uq = FPSCR; }});
573                134: mtfsfi({{
574                    FPSCR = insertCRField(FPSCR, BF + (8 * (1 - W_FIELD)),
575                                          U_FIELD);
576                }});
577                711: mtfsf({{
578                    if (L_FIELD == 1) { FPSCR = Fb_uq; }
579                    else {
580                        for (int i = 0; i < 8; ++i) {
581                            if (bits(FLM, i) == 1) {
582                                int k = 4 * (i + (8 * (1 - W_FIELD)));
583                                FPSCR = insertBits(FPSCR, k + 3, k,
584                                                   bits(Fb_uq, k + 3, k));
585                            }
586                        }
587                    }
588                }});
589                70: mtfsb0({{ FPSCR = insertBits(FPSCR, 31 - BT, 0); }});
590                38: mtfsb1({{ FPSCR = insertBits(FPSCR, 31 - BT, 1); }});
591            }
592        }
593    }
594}
595