aboutsummaryrefslogblamecommitdiffstats
path: root/arch/m68k/fpsp040/util.S
blob: 65b26fa88c60a4918368a2990396ecb1d19b44c6 (plain) (tree)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
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
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747

















                                                              

                                                                






















































































































































































































































































































































































































































































































































































































































































































































                                                                               
|
|	util.sa 3.7 7/29/91
|
|	This file contains routines used by other programs.
|
|	ovf_res: used by overflow to force the correct
|		 result. ovf_r_k, ovf_r_x2, ovf_r_x3 are
|		 derivatives of this routine.
|	get_fline: get user's opcode word
|	g_dfmtou: returns the destination format.
|	g_opcls: returns the opclass of the float instruction.
|	g_rndpr: returns the rounding precision.
|	reg_dest: write byte, word, or long data to Dn
|
|
|		Copyright (C) Motorola, Inc. 1990
|			All Rights Reserved
|
|       For details on the license for this file, please see the
|       file, README, in this same directory.

|UTIL	idnt    2,1 | Motorola 040 Floating Point Software Package

	|section	8

#include "fpsp.h"

	|xref	mem_read

	.global	g_dfmtou
	.global	g_opcls
	.global	g_rndpr
	.global	get_fline
	.global	reg_dest

|
| Final result table for ovf_res. Note that the negative counterparts
| are unnecessary as ovf_res always returns the sign separately from
| the exponent.
|					;+inf
EXT_PINF:	.long	0x7fff0000,0x00000000,0x00000000,0x00000000
|					;largest +ext
EXT_PLRG:	.long	0x7ffe0000,0xffffffff,0xffffffff,0x00000000
|					;largest magnitude +sgl in ext
SGL_PLRG:	.long	0x407e0000,0xffffff00,0x00000000,0x00000000
|					;largest magnitude +dbl in ext
DBL_PLRG:	.long	0x43fe0000,0xffffffff,0xfffff800,0x00000000
|					;largest -ext

tblovfl:
	.long	EXT_RN
	.long	EXT_RZ
	.long	EXT_RM
	.long	EXT_RP
	.long	SGL_RN
	.long	SGL_RZ
	.long	SGL_RM
	.long	SGL_RP
	.long	DBL_RN
	.long	DBL_RZ
	.long	DBL_RM
	.long	DBL_RP
	.long	error
	.long	error
	.long	error
	.long	error


|
|	ovf_r_k --- overflow result calculation
|
| This entry point is used by kernel_ex.
|
| This forces the destination precision to be extended
|
| Input:	operand in ETEMP
| Output:	a result is in ETEMP (internal extended format)
|
	.global	ovf_r_k
ovf_r_k:
	lea	ETEMP(%a6),%a0	|a0 points to source operand
	bclrb	#sign_bit,ETEMP_EX(%a6)
	sne	ETEMP_SGN(%a6)	|convert to internal IEEE format

|
|	ovf_r_x2 --- overflow result calculation
|
| This entry point used by x_ovfl.  (opclass 0 and 2)
|
| Input		a0  points to an operand in the internal extended format
| Output	a0  points to the result in the internal extended format
|
| This sets the round precision according to the user's FPCR unless the
| instruction is fsgldiv or fsglmul or fsadd, fdadd, fsub, fdsub, fsmul,
| fdmul, fsdiv, fddiv, fssqrt, fsmove, fdmove, fsabs, fdabs, fsneg, fdneg.
| If the instruction is fsgldiv of fsglmul, the rounding precision must be
| extended.  If the instruction is not fsgldiv or fsglmul but a force-
| precision instruction, the rounding precision is then set to the force
| precision.

	.global	ovf_r_x2
ovf_r_x2:
	btstb	#E3,E_BYTE(%a6)		|check for nu exception
	beql	ovf_e1_exc		|it is cu exception
ovf_e3_exc:
	movew	CMDREG3B(%a6),%d0		|get the command word
	andiw	#0x00000060,%d0		|clear all bits except 6 and 5
	cmpil	#0x00000040,%d0
	beql	ovff_sgl		|force precision is single
	cmpil	#0x00000060,%d0
	beql	ovff_dbl		|force precision is double
	movew	CMDREG3B(%a6),%d0		|get the command word again
	andil	#0x7f,%d0			|clear all except operation
	cmpil	#0x33,%d0
	beql	ovf_fsgl		|fsglmul or fsgldiv
	cmpil	#0x30,%d0
	beql	ovf_fsgl
	bra	ovf_fpcr		|instruction is none of the above
|					;use FPCR
ovf_e1_exc:
	movew	CMDREG1B(%a6),%d0		|get command word
	andil	#0x00000044,%d0		|clear all bits except 6 and 2
	cmpil	#0x00000040,%d0
	beql	ovff_sgl		|the instruction is force single
	cmpil	#0x00000044,%d0
	beql	ovff_dbl		|the instruction is force double
	movew	CMDREG1B(%a6),%d0		|again get the command word
	andil	#0x0000007f,%d0		|clear all except the op code
	cmpil	#0x00000027,%d0
	beql	ovf_fsgl		|fsglmul
	cmpil	#0x00000024,%d0
	beql	ovf_fsgl		|fsgldiv
	bra	ovf_fpcr		|none of the above, use FPCR
|
|
| Inst is either fsgldiv or fsglmul.  Force extended precision.
|
ovf_fsgl:
	clrl	%d0
	bra	ovf_res

ovff_sgl:
	movel	#0x00000001,%d0		|set single
	bra	ovf_res
ovff_dbl:
	movel	#0x00000002,%d0		|set double
	bra	ovf_res
|
| The precision is in the fpcr.
|
ovf_fpcr:
	bfextu	FPCR_MODE(%a6){#0:#2},%d0 |set round precision
	bra	ovf_res

|
|
|	ovf_r_x3 --- overflow result calculation
|
| This entry point used by x_ovfl. (opclass 3 only)
|
| Input		a0  points to an operand in the internal extended format
| Output	a0  points to the result in the internal extended format
|
| This sets the round precision according to the destination size.
|
	.global	ovf_r_x3
ovf_r_x3:
	bsr	g_dfmtou	|get dest fmt in d0{1:0}
|				;for fmovout, the destination format
|				;is the rounding precision

|
|	ovf_res --- overflow result calculation
|
| Input:
|	a0	points to operand in internal extended format
| Output:
|	a0	points to result in internal extended format
|
	.global	ovf_res
ovf_res:
	lsll	#2,%d0		|move round precision to d0{3:2}
	bfextu	FPCR_MODE(%a6){#2:#2},%d1 |set round mode
	orl	%d1,%d0		|index is fmt:mode in d0{3:0}
	leal	tblovfl,%a1	|load a1 with table address
	movel	%a1@(%d0:l:4),%a1	|use d0 as index to the table
	jmp	(%a1)		|go to the correct routine
|
|case DEST_FMT = EXT
|
EXT_RN:
	leal	EXT_PINF,%a1	|answer is +/- infinity
	bsetb	#inf_bit,FPSR_CC(%a6)
	bra	set_sign	|now go set the sign
EXT_RZ:
	leal	EXT_PLRG,%a1	|answer is +/- large number
	bra	set_sign	|now go set the sign
EXT_RM:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	e_rm_pos
e_rm_neg:
	leal	EXT_PINF,%a1	|answer is negative infinity
	orl	#neginf_mask,USER_FPSR(%a6)
	bra	end_ovfr
e_rm_pos:
	leal	EXT_PLRG,%a1	|answer is large positive number
	bra	end_ovfr
EXT_RP:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	e_rp_pos
e_rp_neg:
	leal	EXT_PLRG,%a1	|answer is large negative number
	bsetb	#neg_bit,FPSR_CC(%a6)
	bra	end_ovfr
e_rp_pos:
	leal	EXT_PINF,%a1	|answer is positive infinity
	bsetb	#inf_bit,FPSR_CC(%a6)
	bra	end_ovfr
|
|case DEST_FMT = DBL
|
DBL_RN:
	leal	EXT_PINF,%a1	|answer is +/- infinity
	bsetb	#inf_bit,FPSR_CC(%a6)
	bra	set_sign
DBL_RZ:
	leal	DBL_PLRG,%a1	|answer is +/- large number
	bra	set_sign	|now go set the sign
DBL_RM:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	d_rm_pos
d_rm_neg:
	leal	EXT_PINF,%a1	|answer is negative infinity
	orl	#neginf_mask,USER_FPSR(%a6)
	bra	end_ovfr	|inf is same for all precisions (ext,dbl,sgl)
d_rm_pos:
	leal	DBL_PLRG,%a1	|answer is large positive number
	bra	end_ovfr
DBL_RP:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	d_rp_pos
d_rp_neg:
	leal	DBL_PLRG,%a1	|answer is large negative number
	bsetb	#neg_bit,FPSR_CC(%a6)
	bra	end_ovfr
d_rp_pos:
	leal	EXT_PINF,%a1	|answer is positive infinity
	bsetb	#inf_bit,FPSR_CC(%a6)
	bra	end_ovfr
|
|case DEST_FMT = SGL
|
SGL_RN:
	leal	EXT_PINF,%a1	|answer is +/-  infinity
	bsetb	#inf_bit,FPSR_CC(%a6)
	bras	set_sign
SGL_RZ:
	leal	SGL_PLRG,%a1	|answer is +/- large number
	bras	set_sign
SGL_RM:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	s_rm_pos
s_rm_neg:
	leal	EXT_PINF,%a1	|answer is negative infinity
	orl	#neginf_mask,USER_FPSR(%a6)
	bras	end_ovfr
s_rm_pos:
	leal	SGL_PLRG,%a1	|answer is large positive number
	bras	end_ovfr
SGL_RP:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	s_rp_pos
s_rp_neg:
	leal	SGL_PLRG,%a1	|answer is large negative number
	bsetb	#neg_bit,FPSR_CC(%a6)
	bras	end_ovfr
s_rp_pos:
	leal	EXT_PINF,%a1	|answer is positive infinity
	bsetb	#inf_bit,FPSR_CC(%a6)
	bras	end_ovfr

set_sign:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	end_ovfr
neg_sign:
	bsetb	#neg_bit,FPSR_CC(%a6)

end_ovfr:
	movew	LOCAL_EX(%a1),LOCAL_EX(%a0) |do not overwrite sign
	movel	LOCAL_HI(%a1),LOCAL_HI(%a0)
	movel	LOCAL_LO(%a1),LOCAL_LO(%a0)
	rts


|
|	ERROR
|
error:
	rts
|
|	get_fline --- get f-line opcode of interrupted instruction
|
|	Returns opcode in the low word of d0.
|
get_fline:
	movel	USER_FPIAR(%a6),%a0	|opcode address
	movel	#0,-(%a7)	|reserve a word on the stack
	leal	2(%a7),%a1	|point to low word of temporary
	movel	#2,%d0		|count
	bsrl	mem_read
	movel	(%a7)+,%d0
	rts
|
|	g_rndpr --- put rounding precision in d0{1:0}
|
|	valid return codes are:
|		00 - extended
|		01 - single
|		10 - double
|
| begin
| get rounding precision (cmdreg3b{6:5})
| begin
|  case	opclass = 011 (move out)
|	get destination format - this is the also the rounding precision
|
|  case	opclass = 0x0
|	if E3
|	    *case RndPr(from cmdreg3b{6:5} = 11  then RND_PREC = DBL
|	    *case RndPr(from cmdreg3b{6:5} = 10  then RND_PREC = SGL
|	     case RndPr(from cmdreg3b{6:5} = 00 | 01
|		use precision from FPCR{7:6}
|			case 00 then RND_PREC = EXT
|			case 01 then RND_PREC = SGL
|			case 10 then RND_PREC = DBL
|	else E1
|	     use precision in FPCR{7:6}
|	     case 00 then RND_PREC = EXT
|	     case 01 then RND_PREC = SGL
|	     case 10 then RND_PREC = DBL
| end
|
g_rndpr:
	bsr	g_opcls		|get opclass in d0{2:0}
	cmpw	#0x0003,%d0	|check for opclass 011
	bnes	op_0x0

|
| For move out instructions (opclass 011) the destination format
| is the same as the rounding precision.  Pass results from g_dfmtou.
|
	bsr	g_dfmtou
	rts
op_0x0:
	btstb	#E3,E_BYTE(%a6)
	beql	unf_e1_exc	|branch to e1 underflow
unf_e3_exc:
	movel	CMDREG3B(%a6),%d0	|rounding precision in d0{10:9}
	bfextu	%d0{#9:#2},%d0	|move the rounding prec bits to d0{1:0}
	cmpil	#0x2,%d0
	beql	unff_sgl	|force precision is single
	cmpil	#0x3,%d0		|force precision is double
	beql	unff_dbl
	movew	CMDREG3B(%a6),%d0	|get the command word again
	andil	#0x7f,%d0		|clear all except operation
	cmpil	#0x33,%d0
	beql	unf_fsgl	|fsglmul or fsgldiv
	cmpil	#0x30,%d0
	beql	unf_fsgl	|fsgldiv or fsglmul
	bra	unf_fpcr
unf_e1_exc:
	movel	CMDREG1B(%a6),%d0	|get 32 bits off the stack, 1st 16 bits
|				;are the command word
	andil	#0x00440000,%d0	|clear all bits except bits 6 and 2
	cmpil	#0x00400000,%d0
	beql	unff_sgl	|force single
	cmpil	#0x00440000,%d0	|force double
	beql	unff_dbl
	movel	CMDREG1B(%a6),%d0	|get the command word again
	andil	#0x007f0000,%d0	|clear all bits except the operation
	cmpil	#0x00270000,%d0
	beql	unf_fsgl	|fsglmul
	cmpil	#0x00240000,%d0
	beql	unf_fsgl	|fsgldiv
	bra	unf_fpcr

|
| Convert to return format.  The values from cmdreg3b and the return
| values are:
|	cmdreg3b	return	     precision
|	--------	------	     ---------
|	  00,01		  0		ext
|	   10		  1		sgl
|	   11		  2		dbl
| Force single
|
unff_sgl:
	movel	#1,%d0		|return 1
	rts
|
| Force double
|
unff_dbl:
	movel	#2,%d0		|return 2
	rts
|
| Force extended
|
unf_fsgl:
	movel	#0,%d0
	rts
|
| Get rounding precision set in FPCR{7:6}.
|
unf_fpcr:
	movel	USER_FPCR(%a6),%d0 |rounding precision bits in d0{7:6}
	bfextu	%d0{#24:#2},%d0	|move the rounding prec bits to d0{1:0}
	rts
|
|	g_opcls --- put opclass in d0{2:0}
|
g_opcls:
	btstb	#E3,E_BYTE(%a6)
	beqs	opc_1b		|if set, go to cmdreg1b
opc_3b:
	clrl	%d0		|if E3, only opclass 0x0 is possible
	rts
opc_1b:
	movel	CMDREG1B(%a6),%d0
	bfextu	%d0{#0:#3},%d0	|shift opclass bits d0{31:29} to d0{2:0}
	rts
|
|	g_dfmtou --- put destination format in d0{1:0}
|
|	If E1, the format is from cmdreg1b{12:10}
|	If E3, the format is extended.
|
|	Dest. Fmt.
|		extended  010 -> 00
|		single    001 -> 01
|		double    101 -> 10
|
g_dfmtou:
	btstb	#E3,E_BYTE(%a6)
	beqs	op011
	clrl	%d0		|if E1, size is always ext
	rts
op011:
	movel	CMDREG1B(%a6),%d0
	bfextu	%d0{#3:#3},%d0	|dest fmt from cmdreg1b{12:10}
	cmpb	#1,%d0		|check for single
	bnes	not_sgl
	movel	#1,%d0
	rts
not_sgl:
	cmpb	#5,%d0		|check for double
	bnes	not_dbl
	movel	#2,%d0
	rts
not_dbl:
	clrl	%d0		|must be extended
	rts

|
|
| Final result table for unf_sub. Note that the negative counterparts
| are unnecessary as unf_sub always returns the sign separately from
| the exponent.
|					;+zero
EXT_PZRO:	.long	0x00000000,0x00000000,0x00000000,0x00000000
|					;+zero
SGL_PZRO:	.long	0x3f810000,0x00000000,0x00000000,0x00000000
|					;+zero
DBL_PZRO:	.long	0x3c010000,0x00000000,0x00000000,0x00000000
|					;smallest +ext denorm
EXT_PSML:	.long	0x00000000,0x00000000,0x00000001,0x00000000
|					;smallest +sgl denorm
SGL_PSML:	.long	0x3f810000,0x00000100,0x00000000,0x00000000
|					;smallest +dbl denorm
DBL_PSML:	.long	0x3c010000,0x00000000,0x00000800,0x00000000
|
|	UNF_SUB --- underflow result calculation
|
| Input:
|	d0	contains round precision
|	a0	points to input operand in the internal extended format
|
| Output:
|	a0	points to correct internal extended precision result.
|

tblunf:
	.long	uEXT_RN
	.long	uEXT_RZ
	.long	uEXT_RM
	.long	uEXT_RP
	.long	uSGL_RN
	.long	uSGL_RZ
	.long	uSGL_RM
	.long	uSGL_RP
	.long	uDBL_RN
	.long	uDBL_RZ
	.long	uDBL_RM
	.long	uDBL_RP
	.long	uDBL_RN
	.long	uDBL_RZ
	.long	uDBL_RM
	.long	uDBL_RP

	.global	unf_sub
unf_sub:
	lsll	#2,%d0		|move round precision to d0{3:2}
	bfextu	FPCR_MODE(%a6){#2:#2},%d1 |set round mode
	orl	%d1,%d0		|index is fmt:mode in d0{3:0}
	leal	tblunf,%a1	|load a1 with table address
	movel	%a1@(%d0:l:4),%a1	|use d0 as index to the table
	jmp	(%a1)		|go to the correct routine
|
|case DEST_FMT = EXT
|
uEXT_RN:
	leal	EXT_PZRO,%a1	|answer is +/- zero
	bsetb	#z_bit,FPSR_CC(%a6)
	bra	uset_sign	|now go set the sign
uEXT_RZ:
	leal	EXT_PZRO,%a1	|answer is +/- zero
	bsetb	#z_bit,FPSR_CC(%a6)
	bra	uset_sign	|now go set the sign
uEXT_RM:
	tstb	LOCAL_SGN(%a0)	|if negative underflow
	beqs	ue_rm_pos
ue_rm_neg:
	leal	EXT_PSML,%a1	|answer is negative smallest denorm
	bsetb	#neg_bit,FPSR_CC(%a6)
	bra	end_unfr
ue_rm_pos:
	leal	EXT_PZRO,%a1	|answer is positive zero
	bsetb	#z_bit,FPSR_CC(%a6)
	bra	end_unfr
uEXT_RP:
	tstb	LOCAL_SGN(%a0)	|if negative underflow
	beqs	ue_rp_pos
ue_rp_neg:
	leal	EXT_PZRO,%a1	|answer is negative zero
	oril	#negz_mask,USER_FPSR(%a6)
	bra	end_unfr
ue_rp_pos:
	leal	EXT_PSML,%a1	|answer is positive smallest denorm
	bra	end_unfr
|
|case DEST_FMT = DBL
|
uDBL_RN:
	leal	DBL_PZRO,%a1	|answer is +/- zero
	bsetb	#z_bit,FPSR_CC(%a6)
	bra	uset_sign
uDBL_RZ:
	leal	DBL_PZRO,%a1	|answer is +/- zero
	bsetb	#z_bit,FPSR_CC(%a6)
	bra	uset_sign	|now go set the sign
uDBL_RM:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	ud_rm_pos
ud_rm_neg:
	leal	DBL_PSML,%a1	|answer is smallest denormalized negative
	bsetb	#neg_bit,FPSR_CC(%a6)
	bra	end_unfr
ud_rm_pos:
	leal	DBL_PZRO,%a1	|answer is positive zero
	bsetb	#z_bit,FPSR_CC(%a6)
	bra	end_unfr
uDBL_RP:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	ud_rp_pos
ud_rp_neg:
	leal	DBL_PZRO,%a1	|answer is negative zero
	oril	#negz_mask,USER_FPSR(%a6)
	bra	end_unfr
ud_rp_pos:
	leal	DBL_PSML,%a1	|answer is smallest denormalized negative
	bra	end_unfr
|
|case DEST_FMT = SGL
|
uSGL_RN:
	leal	SGL_PZRO,%a1	|answer is +/- zero
	bsetb	#z_bit,FPSR_CC(%a6)
	bras	uset_sign
uSGL_RZ:
	leal	SGL_PZRO,%a1	|answer is +/- zero
	bsetb	#z_bit,FPSR_CC(%a6)
	bras	uset_sign
uSGL_RM:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	us_rm_pos
us_rm_neg:
	leal	SGL_PSML,%a1	|answer is smallest denormalized negative
	bsetb	#neg_bit,FPSR_CC(%a6)
	bras	end_unfr
us_rm_pos:
	leal	SGL_PZRO,%a1	|answer is positive zero
	bsetb	#z_bit,FPSR_CC(%a6)
	bras	end_unfr
uSGL_RP:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	us_rp_pos
us_rp_neg:
	leal	SGL_PZRO,%a1	|answer is negative zero
	oril	#negz_mask,USER_FPSR(%a6)
	bras	end_unfr
us_rp_pos:
	leal	SGL_PSML,%a1	|answer is smallest denormalized positive
	bras	end_unfr

uset_sign:
	tstb	LOCAL_SGN(%a0)	|if negative overflow
	beqs	end_unfr
uneg_sign:
	bsetb	#neg_bit,FPSR_CC(%a6)

end_unfr:
	movew	LOCAL_EX(%a1),LOCAL_EX(%a0) |be careful not to overwrite sign
	movel	LOCAL_HI(%a1),LOCAL_HI(%a0)
	movel	LOCAL_LO(%a1),LOCAL_LO(%a0)
	rts
|
|	reg_dest --- write byte, word, or long data to Dn
|
|
| Input:
|	L_SCR1: Data
|	d1:     data size and dest register number formatted as:
|
|	32		5    4     3     2     1     0
|       -----------------------------------------------
|       |        0        |    Size   |  Dest Reg #   |
|       -----------------------------------------------
|
|	Size is:
|		0 - Byte
|		1 - Word
|		2 - Long/Single
|
pregdst:
	.long	byte_d0
	.long	byte_d1
	.long	byte_d2
	.long	byte_d3
	.long	byte_d4
	.long	byte_d5
	.long	byte_d6
	.long	byte_d7
	.long	word_d0
	.long	word_d1
	.long	word_d2
	.long	word_d3
	.long	word_d4
	.long	word_d5
	.long	word_d6
	.long	word_d7
	.long	long_d0
	.long	long_d1
	.long	long_d2
	.long	long_d3
	.long	long_d4
	.long	long_d5
	.long	long_d6
	.long	long_d7

reg_dest:
	leal	pregdst,%a0
	movel	%a0@(%d1:l:4),%a0
	jmp	(%a0)

byte_d0:
	moveb	L_SCR1(%a6),USER_D0+3(%a6)
	rts
byte_d1:
	moveb	L_SCR1(%a6),USER_D1+3(%a6)
	rts
byte_d2:
	moveb	L_SCR1(%a6),%d2
	rts
byte_d3:
	moveb	L_SCR1(%a6),%d3
	rts
byte_d4:
	moveb	L_SCR1(%a6),%d4
	rts
byte_d5:
	moveb	L_SCR1(%a6),%d5
	rts
byte_d6:
	moveb	L_SCR1(%a6),%d6
	rts
byte_d7:
	moveb	L_SCR1(%a6),%d7
	rts
word_d0:
	movew	L_SCR1(%a6),USER_D0+2(%a6)
	rts
word_d1:
	movew	L_SCR1(%a6),USER_D1+2(%a6)
	rts
word_d2:
	movew	L_SCR1(%a6),%d2
	rts
word_d3:
	movew	L_SCR1(%a6),%d3
	rts
word_d4:
	movew	L_SCR1(%a6),%d4
	rts
word_d5:
	movew	L_SCR1(%a6),%d5
	rts
word_d6:
	movew	L_SCR1(%a6),%d6
	rts
word_d7:
	movew	L_SCR1(%a6),%d7
	rts
long_d0:
	movel	L_SCR1(%a6),USER_D0(%a6)
	rts
long_d1:
	movel	L_SCR1(%a6),USER_D1(%a6)
	rts
long_d2:
	movel	L_SCR1(%a6),%d2
	rts
long_d3:
	movel	L_SCR1(%a6),%d3
	rts
long_d4:
	movel	L_SCR1(%a6),%d4
	rts
long_d5:
	movel	L_SCR1(%a6),%d5
	rts
long_d6:
	movel	L_SCR1(%a6),%d6
	rts
long_d7:
	movel	L_SCR1(%a6),%d7
	rts
	|end