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99dee823 | 1 | /* Copyright (C) 2008-2021 Free Software Foundation, Inc. |
d38a64b4 JR |
2 | Contributor: Joern Rennecke <joern.rennecke@embecosm.com> |
3 | on behalf of Synopsys Inc. | |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 3, or (at your option) any later | |
10 | version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | Under Section 7 of GPL version 3, you are granted additional | |
18 | permissions described in the GCC Runtime Library Exception, version | |
19 | 3.1, as published by the Free Software Foundation. | |
20 | ||
21 | You should have received a copy of the GNU General Public License and | |
22 | a copy of the GCC Runtime Library Exception along with this program; | |
23 | see 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 | .L7f800000: | |
69 | .long 0x7f800000 | |
70 | .Ldivtab: | |
71 | .long 0xfc0ffff0 | |
72 | .long 0xf46ffefd | |
73 | .long 0xed1ffd2a | |
74 | .long 0xe627fa8e | |
75 | .long 0xdf7ff73b | |
76 | .long 0xd917f33b | |
77 | .long 0xd2f7eea3 | |
78 | .long 0xcd1fe986 | |
79 | .long 0xc77fe3e7 | |
80 | .long 0xc21fdddb | |
81 | .long 0xbcefd760 | |
82 | .long 0xb7f7d08c | |
83 | .long 0xb32fc960 | |
84 | .long 0xae97c1ea | |
85 | .long 0xaa27ba26 | |
86 | .long 0xa5e7b22e | |
87 | .long 0xa1cfa9fe | |
88 | .long 0x9ddfa1a0 | |
89 | .long 0x9a0f990c | |
90 | .long 0x9667905d | |
91 | .long 0x92df878a | |
92 | .long 0x8f6f7e84 | |
93 | .long 0x8c27757e | |
94 | .long 0x88f76c54 | |
95 | .long 0x85df630c | |
96 | .long 0x82e759c5 | |
97 | .long 0x8007506d | |
98 | .long 0x7d3f470a | |
99 | .long 0x7a8f3da2 | |
100 | .long 0x77ef341e | |
101 | .long 0x756f2abe | |
102 | .long 0x72f7212d | |
103 | .long 0x709717ad | |
104 | .long 0x6e4f0e44 | |
105 | .long 0x6c1704d6 | |
106 | .long 0x69e6fb44 | |
107 | .long 0x67cef1d7 | |
108 | .long 0x65c6e872 | |
109 | .long 0x63cedf18 | |
110 | .long 0x61e6d5cd | |
111 | .long 0x6006cc6d | |
112 | .long 0x5e36c323 | |
113 | .long 0x5c76b9f3 | |
114 | .long 0x5abeb0b7 | |
115 | .long 0x5916a79b | |
116 | .long 0x57769e77 | |
117 | .long 0x55de954d | |
118 | .long 0x54568c4e | |
119 | .long 0x52d6834d | |
120 | .long 0x51667a7f | |
121 | .long 0x4ffe71b5 | |
122 | .long 0x4e9e68f1 | |
123 | .long 0x4d466035 | |
124 | .long 0x4bf65784 | |
125 | .long 0x4aae4ede | |
126 | .long 0x496e4646 | |
127 | .long 0x48363dbd | |
128 | .long 0x47063547 | |
129 | .long 0x45de2ce5 | |
130 | .long 0x44be2498 | |
131 | .long 0x43a61c64 | |
132 | .long 0x4296144a | |
133 | .long 0x41860c0e | |
134 | .long 0x407e03ee | |
135 | __divsf3_support: /* This label makes debugger output saner. */ | |
136 | .Ldenorm_fp1: | |
137 | bclr r6,r6,31 | |
138 | norm.f r12,r6 ; flag for x/0 -> Inf check | |
139 | add r6,r6,r6 | |
140 | rsub r5,r12,16 | |
141 | ror r5,r1,r5 | |
142 | asl r6,r6,r12 | |
143 | bmsk r5,r5,5 | |
144 | ld.as r5,[r3,r5] | |
145 | add r4,r6,r6 | |
146 | ; load latency | |
c0ab1970 | 147 | MPYHU r7,r5,r4 |
d38a64b4 JR |
148 | bic.ne.f 0, \ |
149 | 0x60000000,r0 ; large number / denorm -> Inf | |
150 | beq_s .Linf_NaN | |
151 | asl r5,r5,13 | |
152 | ; wb stall | |
153 | ; slow track | |
154 | sub r7,r5,r7 | |
c0ab1970 | 155 | MPYHU r8,r7,r6 |
d38a64b4 JR |
156 | asl_s r12,r12,23 |
157 | and.f r2,r0,r9 | |
158 | add r2,r2,r12 | |
159 | asl r12,r0,8 | |
160 | ; wb stall | |
161 | bne.d .Lpast_denorm_fp1 | |
162 | .Ldenorm_fp0: | |
c0ab1970 | 163 | MPYHU r8,r8,r7 |
d38a64b4 JR |
164 | bclr r12,r12,31 |
165 | norm.f r3,r12 ; flag for 0/x -> 0 check | |
166 | bic.ne.f 0,0x60000000,r1 ; denorm/large number -> 0 | |
167 | beq_s .Lret0 | |
168 | asl_s r12,r12,r3 | |
169 | asl_s r3,r3,23 | |
170 | add_s r12,r12,r12 | |
171 | add r11,r11,r3 | |
172 | b.d .Lpast_denorm_fp0 | |
173 | mov_s r3,r12 | |
174 | .balign 4 | |
175 | .Linf_NaN: | |
176 | bclr.f 0,r0,31 ; 0/0 -> NaN | |
177 | xor_s r0,r0,r1 | |
178 | bmsk r1,r0,30 | |
179 | bic_s r0,r0,r1 | |
180 | sub.eq r0,r0,1 | |
181 | j_s.d [blink] | |
182 | or r0,r0,r9 | |
183 | .Lret0: | |
184 | xor_s r0,r0,r1 | |
185 | bmsk r1,r0,30 | |
186 | j_s.d [blink] | |
187 | bic_s r0,r0,r1 | |
188 | .Linf_nan_fp1: | |
189 | lsr_s r0,r0,31 | |
190 | bmsk.f 0,r1,22 | |
191 | asl_s r0,r0,31 | |
192 | bne_s 0f ; inf/inf -> nan | |
193 | brne r2,r9,.Lsigned0 ; x/inf -> 0, but x/nan -> nan | |
194 | 0: j_s.d [blink] | |
195 | mov r0,-1 | |
196 | .Lsigned0: | |
197 | .Linf_nan_fp0: | |
198 | tst_s r1,r1 | |
199 | j_s.d [blink] | |
200 | bxor.mi r0,r0,31 | |
201 | .balign 4 | |
202 | .global __divsf3 | |
203 | /* N.B. the spacing between divtab and the sub3 to get its address must | |
204 | be a multiple of 8. */ | |
205 | __divsf3: | |
206 | lsr r2,r1,17 | |
207 | sub3 r3,pcl,55;(.-.Ldivtab) >> 3 | |
208 | bmsk_s r2,r2,5 | |
209 | ld.as r5,[r3,r2] | |
210 | asl r4,r1,9 | |
211 | ld.as r9,[pcl,-114]; [pcl,(-((.-.L7f800000) >> 2))] ; 0x7f800000 | |
c0ab1970 | 212 | MPYHU r7,r5,r4 |
d38a64b4 JR |
213 | asl r6,r1,8 |
214 | and.f r11,r1,r9 | |
215 | bset r6,r6,31 | |
216 | asl r5,r5,13 | |
217 | ; wb stall | |
218 | beq .Ldenorm_fp1 | |
219 | sub r7,r5,r7 | |
c0ab1970 | 220 | MPYHU r8,r7,r6 |
d38a64b4 JR |
221 | breq.d r11,r9,.Linf_nan_fp1 |
222 | and.f r2,r0,r9 | |
223 | beq.d .Ldenorm_fp0 | |
224 | asl r12,r0,8 | |
225 | ; wb stall | |
226 | breq r2,r9,.Linf_nan_fp0 | |
c0ab1970 | 227 | MPYHU r8,r8,r7 |
d38a64b4 JR |
228 | .Lpast_denorm_fp1: |
229 | bset r3,r12,31 | |
230 | .Lpast_denorm_fp0: | |
231 | cmp_s r3,r6 | |
232 | lsr.cc r3,r3,1 | |
233 | add_s r2,r2, /* wait for immediate */ \ | |
234 | /* wb stall */ \ | |
235 | 0x3f000000 | |
236 | sub r7,r7,r8 ; u1.31 inverse, about 30 bit | |
c0ab1970 | 237 | MPYHU r3,r3,r7 |
d38a64b4 JR |
238 | sbc r2,r2,r11 |
239 | xor.f 0,r0,r1 | |
240 | and r0,r2,r9 | |
241 | bxor.mi r0,r0,31 | |
242 | brhs r2, /* wb stall / wait for immediate */ \ | |
243 | 0x7f000000,.Linf_denorm | |
244 | .Lpast_denorm: | |
245 | add_s r3,r3,0x22 ; round to nearest or higher | |
246 | tst r3,0x3c ; check if rounding was unsafe | |
247 | lsr r3,r3,6 | |
248 | jne.d [blink] ; return if rounding was safe. | |
249 | add_s r0,r0,r3 | |
250 | /* work out exact rounding if we fall through here. */ | |
251 | /* We know that the exact result cannot be represented in single | |
252 | precision. Find the mid-point between the two nearest | |
253 | representable values, multiply with the divisor, and check if | |
254 | the result is larger than the dividend. */ | |
255 | add_s r3,r3,r3 | |
256 | sub_s r3,r3,1 | |
257 | mpyu r3,r3,r6 | |
258 | asr.f 0,r0,1 ; for round-to-even in case this is a denorm | |
259 | rsub r2,r9,25 | |
260 | asl_s r12,r12,r2 | |
261 | ; wb stall | |
262 | ; slow track | |
263 | sub.f 0,r12,r3 | |
264 | j_s.d [blink] | |
265 | sub.mi r0,r0,1 | |
266 | /* For denormal results, it is possible that an exact result needs | |
267 | rounding, and thus the round-to-even rule has to come into play. */ | |
268 | .Linf_denorm: | |
269 | brlo r2,0xc0000000,.Linf | |
270 | .Ldenorm: | |
271 | asr_s r2,r2,23 | |
272 | bic r0,r0,r9 | |
273 | neg r9,r2 | |
274 | brlo.d r9,25,.Lpast_denorm | |
275 | lsr r3,r3,r9 | |
276 | /* Fall through: return +- 0 */ | |
277 | j_s [blink] | |
278 | .Linf: | |
279 | j_s.d [blink] | |
280 | or r0,r0,r9 | |
281 | ENDFUNC(__divsf3) |