![[first]](../icons/first.png){kind=icon}
![[previous]](../icons/n_left.png){kind=icon}
![[next]](../icons/n_right.png){kind=icon}
![[last]](../icons/last.png){kind=icon}
![[top]](../icons/n_top.png){kind=icon}
![[bottom]](../icons/bottom.png){kind=icon}
![[index]](../icons/index.png){kind=icon}
![[help]](../icons/help.png){kind=icon}
*/
1 /*
2 * vim: filetype=c:tabstop=4:ai:expandtab
3 * SPDX-License-Identifier: ICU
4 * scspell-id: 9868415b-f62d-11ec-9c75-80ee73e9b8e7
5 *
6 * ---------------------------------------------------------------------------
7 *
8 * Copyright (c) 2000-2009 IBM Corporation
9 * Copyright (c) 2012-2016 Harry Reed
10 * Copyright (c) 2013-2016 Charles Anthony
11 * Copyright (c) 2017 Michal Tomek
12 * Copyright (c) 2021-2023 The DPS8M Development Team
13 *
14 * All rights reserved.
15 *
16 * This software is made available under the terms of the ICU
17 * License, version 1.8.1 or later. For more details, see the
18 * LICENSE.md file at the top-level directory of this distribution.
19 *
20 * ---------------------------------------------------------------------------
21 */
22
23 #include <stdio.h>
24
25 #include "dps8.h"
26 #include "dps8_sys.h"
27 #include "dps8_faults.h"
28 #include "dps8_scu.h"
29 #include "dps8_iom.h"
30 #include "dps8_cable.h"
31 #include "dps8_cpu.h"
32 #include "dps8_decimal.h"
33 #include "dps8_eis.h"
34 #include "dps8_utils.h"
35
36 /* ------------------------------------------------------------------ */
37 /* HWR 6/28/14 18:54 derived from ...... */
38 /* decContextDefault(...) */
39 /* */
40 /* decContextDefaultDPS8 -- initialize a context structure */
41 /* */
42 /* Similar to decContextDefault EXCEPT digits are set to 65 for our */
43 /* dps8 simulator (add additional features as required */
44 /* */
45 /* ------------------------------------------------------------------ */
46 decContext * decContextDefaultDPS8(decContext *context)
/* ![[next]](../icons/right.png)
![[first]](../icons/n_first.png)
![[top]](../icons/top.png)
*/
47 {
48 decContextDefault(context, DEC_INIT_BASE);
49 context->traps=0;
50
51 context->digits = 65;
52
53 return context;
54 }
55
56 /* ------------------------------------------------------------------ */
57 /* HWR 3/21/16 19:54 derived from ...... */
58 /* decContextDefault(...) */
59 /* */
60 /* decContextDefaultDPS8 -- initialize a context structure */
61 /* */
62 /* Similar to decContextDefault EXCEPT digits are set to 126 for our */
63 /* dps8 simulators mpXd instructions */
64 /* */
65 /* ------------------------------------------------------------------ */
66 decContext * decContextDefaultDPS8Mul(decContext *context)
/* ![[previous]](../icons/left.png)
*/
67 {
68 decContextDefault(context, DEC_INIT_BASE);
69 context->traps = 0;
70
71 context->digits = 63 + 63; // worse case for multiply
72
73 return context;
74 }
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97 decNumber * decBCD9ToNumber(const word9 *bcd, Int length, const Int scale, decNumber *dn)
/* */
98 {
99 const word9 *last=bcd+length-1; // -> last byte
100 const word9 *first; // -> first non-zero byte
101 uInt nib; // work nibble
102 Unit *up=dn->lsu; // output pointer
103 Int digits; // digits count
104 Int cut=0; // phase of output
105
106 decNumberZero(dn); // default result
107 //last = &bcd[length-1];
108 //nib = *last & 0x0f; // get the sign
109 //if (nib==DECPMINUS || nib==DECPMINUSALT) dn->bits=DECNEG;
110 //else if (nib<=9) return NULL; // not a sign nibble
111
112 // skip leading zero bytes [final byte is always non-zero, due to sign]
113 //for (first=bcd; *first==0;) first++;
114
115 //Also, a bug in decBCD9ToNumber; in the input is all zeros, the skip leading zeros code wanders off the end of the input buffer....
116 for (first=bcd; *first==0 && first <= last;)
117 first++;
118
119 digits=(Int)(last-first)+1; // calculate digits ..
120 //if ((*first & 0xf0)==0) digits--; // adjust for leading zero nibble
121 if (digits!=0)
122 dn->digits=digits; // count of actual digits [if 0,
123 // leave as 1]
124
125 // check the adjusted exponent; note that scale could be unbounded
126 dn->exponent=-scale; // set the exponent
127 if (scale>=0) // usual case
128 {
129 if ((dn->digits-scale-1)<-DECNUMMAXE) // underflow
130 {
131 decNumberZero(dn);
132 //return NULL;
133 // XXX check subfault
134 doFault (FAULT_IPR, fst_ill_proc, "decBCD9ToNumber underflow");
135 }
136 }
137 else // -ve scale; +ve exponent
138 {
139 // need to be careful to avoid wrap, here, also BADINT case
140 if ((scale<-DECNUMMAXE) // overflow even without digits
141 || ((dn->digits-scale-1)>DECNUMMAXE)) // overflow
142 {
143 decNumberZero(dn);
144 //return NULL;
145 // XXX check subfault
146 doFault (FAULT_IPR, fst_ill_proc, "decBCD9ToNumber overflow");
147 }
148 }
149 if (digits==0)
150 return dn; // result was zero
151
152 // copy the digits to the number's units, starting at the lsu
153 // [unrolled]
154 for (;last >= bcd;) // forever
155 {
156 nib=(unsigned)(*last & 0x0f);
157 // got a digit, in nib
158 //if (nib>9) {decNumberZero(dn); return NULL;} // bad digit
159 if (nib > 9)
160 doFault (FAULT_IPR, fst_ill_dig, "decBCD9ToNumber ill digit");
161
162 if (cut==0)
163 *up=(Unit)nib;
164 else
165 *up=(Unit)(*up+nib*DECPOWERS[cut]);
166 digits--;
167 if (digits==0)
168 break; // got them all
169 cut++;
170 if (cut==DECDPUN)
171 {
172 up++;
173 cut=0;
174 }
175 last--; // ready for next
176
177 // nib = *last & 0x0f; // get right nibble
178 // if (nib>9) {decNumberZero(dn); return NULL;}
179 //
180 // // got a digit, in nib
181 // if (cut==0) *up=(Unit)nib;
182 // else *up=(Unit)(*up+nib*DECPOWERS[cut]);
183 // digits--;
184 // if (digits==0) break; // got them all
185 // cut++;
186 // if (cut==DECDPUN) {
187 // up++;
188 // cut=0;
189 // }
190 } // forever
191
192 return dn;
193 } // decBCD9ToNumber
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705 char *formatDecimal (uint8_t * out, decContext *set, decNumber *r, int nout, int s, int sf, bool R, bool *OVR, bool *TRUNC) {
/* */
706 decNumber _sf;
707 decNumber _r2;
708 decNumber * r2 = & _r2;
709 enum rounding safeR = decContextGetRounding (set); // save rounding mode
710 int safe = set->digits;
711
712 * OVR = false;
713 * TRUNC = false;
714
715 // CSFL isn't rescaled and can't overflow
716 if (s != CSFL) {
717
718 // rescale to sf first
719 // AL39: If N2 is not large enough to hold the integer part of C(Y-charn1) _as rescaled by SF2_, an overflow condition exists
720 // ET 336
721 if (sf != r->exponent) {
722 if (!R) {
723 decContextSetRounding (set, DEC_ROUND_DOWN); // Round towards 0 (truncation). ISOLTS 815 09b
724 if (sf > r->exponent) // ET 330: truncation due to: output sf > input sf or exponent
725 * TRUNC = true;
726 }
727 decNumberFromInt32 (& _sf, sf);
728
729
730
731
732
733
734
735
736
737
738
739
740
741 if (r->exponent > sf)
742 set->digits = min (DECNUMDIGITS, max (set->digits, r->digits + r->exponent - sf));
743 decNumberRescale (r, r, & _sf, set);
744 if (decContextGetStatus (set) == DEC_Invalid_operation) {
745 //sim_debug (DBG_TRACE, & cpu_dev, "formatD DEC_Invalid_operation\r\n");
746 decNumberZero (r);
747 * OVR = true;
748 }
749 set->digits = safe;
750
751
752 }
753
754 // check for overflow and if it occurs, adjust the operand
755
756 decContextSetRounding (set, DEC_ROUND_DOWN); // Round towards 0 (truncation).
757 decNumberToIntegralValue (r2, r, set);
758
759 int r2digits = r2->digits;
760 if (decNumberIsZero (r2))
761 r2digits = 0;
762
763 // if sf< 0, this reduces number of integer slots available
764 // if sf>=0, this doesn't change anything, nout integer slots are available
765 // ET 275, ET 336
766 if (nout + min (sf,0) < r2digits) {
767
768 // discard overflowing digits
769 // note that this may set zero flag: ISOLTS-810 01l
770 set->digits = r2digits - (nout + min (sf,0));
771 decNumberPlus (r2, r, set);
772 set->digits = safe;
773
774 decNumberSubtract(r, r, r2, set);
775
776 * OVR = true;
777
778 }
779 decContextSetRounding (set, safeR);
780
781 }
782
783 if (nout < r->digits) { // not enough space to move all digits
784 // round or truncate
785 if (! R) {
786 decContextSetRounding(set, DEC_ROUND_DOWN); // Round towards 0 (truncation).
787 // truncation flag is independent of whether overflow occurred: ISOLTS-810 01k, 815 09b
788 * TRUNC = true;
789 }
790 set->digits = nout;
791 decNumberPlus (r, r, set);
792 set->digits = safe;
793
794 decContextSetRounding (set, safeR); // restore rounding mode
795 }
796
797
798
799
800
801 // write out the digits
802 // note that even CSFL is aligned right - ISOLTS-810 05d
803 uint8_t tmp[256];
804 decNumberGetBCD (r,tmp);
805 int justif = nout - r->digits;
806 for (int i = 0; i < nout; i ++) {
807 if (i < justif)
808 out [i] = '0';
809 else
810 out [i] = tmp [i - justif] + '0';
811 }
812 out [nout] = 0;
813
814 return (char *) out;
815 }
816
817 #ifndef QUIET_UNUSED
818 // If the lhs is less than the rhs in the total order then the number
819 // will be set to the value -1. If they are equal, then number is set
820 // to 0. If the lhs is greater than the rhs then the number will be
821 // set to the value 1.
822 int decCompare(decNumber *lhs, decNumber *rhs, decContext *set)
/* */
823 {
824 decNumber _cmp, *cmp;
825 cmp = decNumberCompareTotal(&_cmp, lhs, rhs, set);
826
827 if (decNumberIsZero(cmp))
828 return 0; // lhs == rhs
829
830 if (decNumberIsNegative(cmp))
831 return -1; // lhs < rhs
832
833 return 1; // lhs > rhs
834 }
835 #endif
836
837 int decCompareMAG(decNumber *lhs, decNumber *rhs, decContext *set)
/* ![[last]](../icons/n_last.png)
*/
838 {
839 decNumber _cmpm, *cmpm;
840 cmpm = decNumberCompareTotalMag(&_cmpm, lhs, rhs, set);
841
842 if (decNumberIsZero(cmpm))
843 return 0; // lhs == rhs
844
845 if (decNumberIsNegative(cmpm))
846 return -1; // lhs < rhs
847
848 return 1; // lhs > rhs
849 }
850
851
852
853
854
855
856
857
858
859
860
![[bottom]](../icons/n_bottom.png){kind=icon}
*/