m68k/math-emu/fp_util.S

23  * the restrictions contained in a BSD-style copyright.)
63 	tst.l	(TASK_MM-8,%a2)
65 	tst.l	(TASK_MM-4,%a2)
69 1:	printf	,"oops:%p,%p,%p\n",3,%a2@(TASK_MM-8),%a2@(TASK_MM-4),%a2@(TASK_MM)
94 	| args:	%d0 = source (32-bit long)
98 	printf	PCONV,"l2e: %p -> %p(",2,%d0,%a0
125 	| args:	%d0 = source (single-precision fp value)
129 	printf	PCONV,"s2e: %p -> %p(",2,%d0,%a0
139 	add.w	#0x3fff-0x7f,%d1	| re-bias the exponent.
152 	move.w	#0x4000-0x7f,%d1
164 	printf	PCONV,"d2e: %p%p -> %p(",3,%d0,%d1,%a0
177 	add.w	#0x3fff-0x3ff,%d1	| re-bias the exponent.
187 	or.l	%d1,-(%a0)
197 	move.w	#0x4000-0x3ff,%d1
260 	tst.b	(1,%a0)			| to -inf
275 	move.b	(-4,%a0),%d0
279 	clr.w	-(%a0)
289 	move.w	-(%a0),%d2
298 	| fancy 64-bit double-shift begins here
308 	or.l	%d1,-(%a0)
312 	move.b	(-4,%a0),%d0
316 	clr.b	(-4,%a0)
322 	move.b	%d0,(-4,%a0)
331 	move.w	-(%a0),%d2
347 	move.b	(-4,%a0),%d0
348 	clr.b	(-4,%a0)
366 	move.w	-(%a0),%d2
377 1:	clr.b	(-4,%a0)
388 	move.b	%d0,(-4,%a0)
400 	move.l	%d0,-(%a0)
484 	tst.b	(1,%a0)			| to -inf
500 	move.b	(-4,%a0),%d0
504 	clr.w	-(%a0)
513 	move.w	-(%a0),%d2
523 	| This is exactly the same 64-bit double shift as seen above.
533 	or.l	%d1,-(%a0)
537 	move.b	(-4,%a0),%d0
541 	clr.b	(-4,%a0)
547 	move.b	%d0,(-4,%a0)
556 	move.w	-(%a0),%d2
573 	move.b	(-4,%a0),%d0
574 	clr.b	(-4,%a0)
592 	move.w	-(%a0),%d2
603 1:	clr.b	(-4,%a0)
614 	move.b	%d0,(-4,%a0)
634 	clr.l	(-4,%a0)
640 	move.l	%d0,(-4,%a0)
647 	| 2:	Round to -Infinity
656 	| normalize an extended with double (52-bit) precision
668 	sub.w	#0x4000-0x3ff,%d2	| will the exponent fit?
678 	jne	fp_nd_checkround	| Are they non-zero?
689 	and.w	#0xf800,(2,%a0)		| clear bits 0-10
697 	| IEEE754-specified "round to even" behaviour.  If the guard
699 	| in grade-school arithmetic (i.e. 1.5 rounds to 2.0)
710 	addq.l	#1,-(%a0)		| extend to high lword
716 	addq.w	#1,-(%a0)
727 	| Round to +Inf or -Inf.  High word of %d2 contains the
729 	swap	%d2			| to -inf
741 	move.w	#0x3c01,(-2,%a0)	| 2**-1022
745 	| Again, another 64-bit double shift.
761 	bset	#0,%d0			| Yes, so set the "sticky bit".
763 	| Another 64-bit single shift and store
776 	bset	#0,%d0			| Sticky bit.
799 	| i.e. pathologically small (exponent is 2**-16383) numbers.
805 	clr.l	-(%a0)
806 	move.w	#0x3c01,-(%a0)		| i.e. 2**-1022
819 1:	move.w	#0x7fff,(-2,%a0)
830 	tst.b	(-3,%a0)		| to -inf
833 4:	tst.b	(-3,%a0)		| to +inf
835 5:	move.w	#0x43fe,(-2,%a0)
836 	moveq	#-1,%d0
850 	| normalize an extended with single (23-bit) precision
862 	sub.w	#0x4000-0x7f,%d2	| will the exponent fit?
870 	| Set a sticky bit if it is non-zero.  This should only
871 	| affect the rounding in what would otherwise be equal-
877 	jne	fp_ns_checkround	| Are they non-zero?
886 	clr.b	-(%a0)			| clear low byte of high lword
905 	addq.w	#1,-(%a0)
917 	tst.b	(-3,%a0)		| to -inf
920 3:	tst.b	(-3,%a0)		| to +inf
927 	move.w	#0x3f81,(-2,%a0)	| 2**-126
931 	| a 32-bit shift.
941 	bset	#0,%d0			| Sticky bit.
946 	bset	#0,%d0			| Sticky bit.
961 1:	move.w	#0x7fff,(-2,%a0)
972 	tst.b	(-3,%a0)		| to -inf
975 4:	tst.b	(-3,%a0)		| to +inf
977 5:	move.w	#0x407e,(-2,%a0)
993 	| i.e. pathologically small (exponent is 2**-16383) numbers.
999 	clr.l	-(%a0)
1000 	move.w	#0x3f81,-(%a0)		| i.e. 2**-126
1013 	| normalize an extended with single (23-bit) precision
1030 	| Set a sticky bit if it is non-zero.  This should only
1031 	| affect the rounding in what would otherwise be equal-
1037 	jne	fp_nsf_checkround	| Are they non-zero?
1046 	clr.b	-(%a0)			| clear low byte of high lword
1065 	addq.w	#1,-(%a0)
1077 	tst.b	(-3,%a0)		| to -inf
1080 3:	tst.b	(-3,%a0)		| to +inf
1091 1:	move.w	#0x7fff,(-2,%a0)
1102 	tst.b	(-3,%a0)		| to -inf
1105 4:	tst.b	(-3,%a0)		| to +inf
1107 5:	move.w	#0x407e,(-2,%a0)
1134 	.set	inf,(1<<(\b-1))-1	| i.e. MAXINT
1156 9:	tst.w	(-4,%a0)
1160 	printf	PCONV,"-> %p\n",1,%d0
1165 1:	printf	PCONV,"-> %p\n",1,%d0
1192 	tst.w	(-4,%a0)		| to -inf
1195 3:	tst.w	(-4,%a0)		| to +inf
1198 	| we are only want -2**127 get correctly rounded here,
1225 	tst.w	(-4,%a0)		| to -inf
1229 2:	tst.w	(-4,%a0)		| to +inf
1232 3:	printf	PCONV,"-> %p\n",1,%d0
1237 	tst.w	(-4,%a0)
1240 1:	printf	PCONV,"-> %p\n",1,%d0
1253 1:	printf	PCONV,"-> %p\n",1,%d0
1277 1:	sub.w	#0x3fff-0x3ff,%d2
1298 	getuser.l %a1@(-4),%d0,fp_err_ua2,%a1
1315 1:	sub.w	#0x3fff-0x7f,%d1
1375 	bset	#FPSR_CC_NEG-24,%d0	| N bit
1379 	moveq	#FPSR_CC_Z-24,%d1
1386 2:	moveq	#FPSR_CC_NAN-24,%d1
1392 	moveq	#FPSR_CC_INF-24,%d1