1/* Copyright (C) 2008-2020 Free Software Foundation, Inc.
2   Contributor: Joern Rennecke <joern.rennecke@embecosm.com>
3		on behalf of Synopsys Inc.
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 3, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15for more details.
16
17Under Section 7 of GPL version 3, you are granted additional
18permissions described in the GCC Runtime Library Exception, version
193.1, as published by the Free Software Foundation.
20
21You should have received a copy of the GNU General Public License and
22a copy of the GCC Runtime Library Exception along with this program;
23see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
24<http://www.gnu.org/licenses/>.  */
25
26/*
27   - calculate 15..18 bit inverse using a table of approximating polynoms.
28     precision is higher for polynoms used to evaluate input with larger
29     value.
30   - do one newton-raphson iteration step to double the precision,
31     then multiply this with the divisor
32	-> more time to decide if dividend is subnormal
33     - the worst error propagation is on the side of the value range
34       with the least initial defect, thus giving us about 30 bits precision.
35 */
36#include "../arc-ieee-754.h"
37
38#if 0 /* DEBUG */
39	.global __divsf3
40	FUNC(__divsf3)
41	.balign 4
42__divsf3:
43	push_s blink
44	push_s r1
45	bl.d __divsf3_c
46	push_s r0
47	ld_s r1,[sp,4]
48	st_s r0,[sp,4]
49	bl.d __divsf3_asm
50	pop_s r0
51	pop_s r1
52	pop_s blink
53	cmp r0,r1
54#if 1
55	bne abort
56	jeq_s [blink]
57	b abort
58#else
59	bne abort
60	j_s [blink]
61#endif
62	ENDFUNC(__divsf3)
63#define __divsf3 __divsf3_asm
64#endif /* DEBUG */
65
66	FUNC(__divsf3)
67	.balign 4
68.Ldivtab:
69	.long 0xfc0ffff0
70	.long 0xf46ffefd
71	.long 0xed1ffd2a
72	.long 0xe627fa8e
73	.long 0xdf7ff73b
74	.long 0xd917f33b
75	.long 0xd2f7eea3
76	.long 0xcd1fe986
77	.long 0xc77fe3e7
78	.long 0xc21fdddb
79	.long 0xbcefd760
80	.long 0xb7f7d08c
81	.long 0xb32fc960
82	.long 0xae97c1ea
83	.long 0xaa27ba26
84	.long 0xa5e7b22e
85	.long 0xa1cfa9fe
86	.long 0x9ddfa1a0
87	.long 0x9a0f990c
88	.long 0x9667905d
89	.long 0x92df878a
90	.long 0x8f6f7e84
91	.long 0x8c27757e
92	.long 0x88f76c54
93	.long 0x85df630c
94	.long 0x82e759c5
95	.long 0x8007506d
96	.long 0x7d3f470a
97	.long 0x7a8f3da2
98	.long 0x77ef341e
99	.long 0x756f2abe
100	.long 0x72f7212d
101	.long 0x709717ad
102	.long 0x6e4f0e44
103	.long 0x6c1704d6
104	.long 0x69e6fb44
105	.long 0x67cef1d7
106	.long 0x65c6e872
107	.long 0x63cedf18
108	.long 0x61e6d5cd
109	.long 0x6006cc6d
110	.long 0x5e36c323
111	.long 0x5c76b9f3
112	.long 0x5abeb0b7
113	.long 0x5916a79b
114	.long 0x57769e77
115	.long 0x55de954d
116	.long 0x54568c4e
117	.long 0x52d6834d
118	.long 0x51667a7f
119	.long 0x4ffe71b5
120	.long 0x4e9e68f1
121	.long 0x4d466035
122	.long 0x4bf65784
123	.long 0x4aae4ede
124	.long 0x496e4646
125	.long 0x48363dbd
126	.long 0x47063547
127	.long 0x45de2ce5
128	.long 0x44be2498
129	.long 0x43a61c64
130	.long 0x4296144a
131	.long 0x41860c0e
132	.long 0x407e03ee
133.L7f800000:
134	.long 0x7f800000
135	.balign 4
136	.global __divsf3_support
137__divsf3_support:
138.Linf_NaN:
139	bclr.f 0,r0,31 ; 0/0 -> NaN
140	xor_s r0,r0,r1
141	bmsk r1,r0,30
142	bic_s r0,r0,r1
143	sub.eq r0,r0,1
144	j_s.d [blink]
145	or r0,r0,r9
146.Lret0:
147	xor_s r0,r0,r1
148	bmsk r1,r0,30
149	j_s.d [blink]
150	bic_s r0,r0,r1
151/* N.B. the spacing between divtab and the sub3 to get its address must
152   be a multiple of 8.  */
153__divsf3:
154	lsr r2,r1,17
155	sub3 r3,pcl,37 ; (.-.Ldivtab) >> 3
156	bmsk_s r2,r2,5
157	ld.as r5,[r3,r2]
158	asl r4,r1,9
159	ld.as r9,[pcl,-13]; [pcl,(-((.-.L7f800000) >> 2))] ; 0x7f800000
160	mulu64 r5,r4
161	and.f r11,r1,r9
162	asl r6,r1,8
163	bset r6,r6,31
164	beq.d .Ldenorm_fp1
165	asl r5,r5,13
166	breq.d r11,r9,.Linf_nan_fp1
167	and.f r2,r0,r9
168	sub r7,r5,mhi
169	mulu64 r7,r6
170	beq.d .Ldenorm_fp0
171	asl r12,r0,8
172	breq.d r2,r9,.Linf_nan_fp0
173	mulu64 mhi,r7
174.Lpast_denorm_fp1:
175	bset r3,r12,31
176.Lpast_denorm_fp0:
177	cmp_s r3,r6
178	lsr.cc r3,r3,1
179	add_s r2,r2, /* wait for immediate */ \
180		0x3f000000
181	sub r7,r7,mhi ; u1.31 inverse, about 30 bit
182	mulu64 r3,r7
183	sbc r2,r2,r11
184	xor.f 0,r0,r1
185	and r0,r2,r9
186	bclr r3,r9,23 ; 0x7f000000
187	brhs.d r2,r3,.Linf_denorm
188	bxor.mi r0,r0,31
189.Lpast_denorm:
190	add r3,mhi,0x22 ; round to nearest or higher
191	tst r3,0x3c ; check if rounding was unsafe
192	lsr r3,r3,6
193	jne.d [blink] ; return if rounding was safe.
194	add_s r0,r0,r3
195        /* work out exact rounding if we fall through here.  */
196        /* We know that the exact result cannot be represented in single
197           precision.  Find the mid-point between the two nearest
198           representable values, multiply with the divisor, and check if
199           the result is larger than the dividend.  */
200        add_s r3,r3,r3
201        sub_s r3,r3,1
202        mulu64 r3,r6
203	asr.f 0,r0,1 ; for round-to-even in case this is a denorm
204	rsub r2,r9,25
205        asl_s r12,r12,r2
206        sub.f 0,r12,mlo
207        j_s.d [blink]
208        sub.mi r0,r0,1
209.Linf_nan_fp1:
210	lsr_s r0,r0,31
211	bmsk.f 0,r1,22
212	asl_s r0,r0,31
213	bne_s 0f ; inf/inf -> nan
214	brne r2,r9,.Lsigned0 ; x/inf -> 0, but x/nan -> nan
2150:	j_s.d [blink]
216	mov r0,-1
217.Lsigned0:
218.Linf_nan_fp0:
219	tst_s r1,r1
220	j_s.d [blink]
221	bxor.mi r0,r0,31
222	.balign 4
223	.global __divsf3
224/* For denormal results, it is possible that an exact result needs
225   rounding, and thus the round-to-even rule has to come into play.  */
226.Linf_denorm:
227	brlo r2,0xc0000000,.Linf
228.Ldenorm:
229	asr_s r2,r2,23
230	bic r0,r0,r9
231	neg r9,r2
232	brlo.d r9,25,.Lpast_denorm
233	lsr r3,mlo,r9
234	/* Fall through: return +- 0 */
235	j_s [blink]
236.Linf:
237	j_s.d [blink]
238	or r0,r0,r9
239	.balign 4
240.Ldenorm_fp1:
241	bclr r6,r6,31
242	norm.f r12,r6 ; flag for x/0 -> Inf check
243	add r6,r6,r6
244	rsub r5,r12,16
245	ror r5,r1,r5
246	asl r6,r6,r12
247	bmsk r5,r5,5
248	ld.as r5,[r3,r5]
249	add r4,r6,r6
250	; load latency
251	mulu64 r5,r4
252	bic.ne.f 0, \
253		0x60000000,r0 ; large number / denorm -> Inf
254	asl r5,r5,13
255	sub r7,r5,mhi
256	beq.d .Linf_NaN
257	mulu64 r7,r6
258	asl_s r12,r12,23
259	and.f r2,r0,r9
260	add_s r2,r2,r12
261	asl r12,r0,8
262	bne.d .Lpast_denorm_fp1
263.Ldenorm_fp0: mulu64 mhi,r7
264	bclr r12,r12,31
265	norm.f r3,r12 ; flag for 0/x -> 0 check
266	bic.ne.f 0,0x60000000,r1 ; denorm/large number -> 0
267	beq_s .Lret0
268	asl_s r12,r12,r3
269	asl_s r3,r3,23
270	add_s r12,r12,r12
271	add r11,r11,r3
272	b.d .Lpast_denorm_fp0
273	mov_s r3,r12
274	ENDFUNC(__divsf3)
275