Bug Summary

File:root/firefox-clang/third_party/rust/glslopt/glsl-optimizer/src/util/softfloat.c
Warning:line 432, column 10
The expression uses uninitialized memory

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-unknown-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name softfloat.c -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -ffp-contract=off -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/root/firefox-clang/third_party/rust/glslopt -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/root/firefox-clang/third_party/rust/glslopt -resource-dir /usr/lib/llvm-21/lib/clang/21 -include /root/firefox-clang/config/gcc_hidden.h -include /root/firefox-clang/obj-x86_64-pc-linux-gnu/mozilla-config.h -I glsl-optimizer/include -I glsl-optimizer/src/mesa -I glsl-optimizer/src/mapi -I glsl-optimizer/src/compiler -I glsl-optimizer/src/compiler/glsl -I glsl-optimizer/src/gallium/auxiliary -I glsl-optimizer/src/gallium/include -I glsl-optimizer/src -I glsl-optimizer/src/util -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/system_wrappers -U _FORTIFY_SOURCE -D _FORTIFY_SOURCE=2 -D _GLIBCXX_ASSERTIONS -D DEBUG=1 -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include/nspr -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include/nss -D MOZILLA_CLIENT -D MOZILLA_CONFIG_H -D __STDC_FORMAT_MACROS -D _GNU_SOURCE -D HAVE_ENDIAN_H -D HAVE_PTHREAD -D HAVE_TIMESPEC_GET -D MOZ_INCLUDE_MOZALLOC_H -D mozilla_throw_gcc_h -internal-isystem /usr/lib/llvm-21/lib/clang/21/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/14/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-error=tautological-type-limit-compare -Wno-range-loop-analysis -Wno-error=deprecated-declarations -Wno-error=array-bounds -Wno-error=free-nonheap-object -Wno-error=atomic-alignment -Wno-error=deprecated-builtins -Wno-psabi -Wno-error=builtin-macro-redefined -Wno-unknown-warning-option -ferror-limit 19 -fstrict-flex-arrays=1 -stack-protector 2 -fstack-clash-protection -ftrivial-auto-var-init=pattern -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -vectorize-loops -vectorize-slp -analyzer-checker optin.performance.Padding -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2025-06-27-100320-3286336-1 -x c glsl-optimizer/src/util/softfloat.c
1/*
2 * License for Berkeley SoftFloat Release 3e
3 *
4 * John R. Hauser
5 * 2018 January 20
6 *
7 * The following applies to the whole of SoftFloat Release 3e as well as to
8 * each source file individually.
9 *
10 * Copyright 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018 The Regents of the
11 * University of California. All rights reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions are met:
15 *
16 * 1. Redistributions of source code must retain the above copyright notice,
17 * this list of conditions, and the following disclaimer.
18 *
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions, and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 *
23 * 3. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
28 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
29 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
30 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
31 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
32 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
33 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
34 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 *
38 *
39 * The functions listed in this file are modified versions of the ones
40 * from the Berkeley SoftFloat 3e Library.
41 *
42 * Their implementation correctness has been checked with the Berkeley
43 * TestFloat Release 3e tool for x86_64.
44 */
45
46#include "rounding.h"
47#include "bitscan.h"
48#include "softfloat.h"
49
50#if defined(BIG_ENDIAN4321)
51#define word_incr-1 -1
52#define index_word(total, n)((total) - 1 - (n)) ((total) - 1 - (n))
53#define index_word_hi(total)0 0
54#define index_word_lo(total)((total) - 1) ((total) - 1)
55#define index_multiword_hi(total, n)0 0
56#define index_multiword_lo(total, n)((total) - (n)) ((total) - (n))
57#define index_multiword_hi_but(total, n)0 0
58#define index_multiword_lo_but(total, n)(n) (n)
59#else
60#define word_incr-1 1
61#define index_word(total, n)((total) - 1 - (n)) (n)
62#define index_word_hi(total)0 ((total) - 1)
63#define index_word_lo(total)((total) - 1) 0
64#define index_multiword_hi(total, n)0 ((total) - (n))
65#define index_multiword_lo(total, n)((total) - (n)) 0
66#define index_multiword_hi_but(total, n)0 (n)
67#define index_multiword_lo_but(total, n)(n) 0
68#endif
69
70typedef union { double f; int64_t i; uint64_t u; } di_type;
71typedef union { float f; int32_t i; uint32_t u; } fi_type;
72
73const uint8_t count_leading_zeros8[256] = {
74 8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
75 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
76 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
77 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
78 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
79 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
80 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
81 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
82 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
83 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
84 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
85 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
86 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
87 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
88 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
89 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
90};
91
92/**
93 * \brief Shifts 'a' right by the number of bits given in 'dist', which must be in
94 * the range 1 to 63. If any nonzero bits are shifted off, they are "jammed"
95 * into the least-significant bit of the shifted value by setting the
96 * least-significant bit to 1. This shifted-and-jammed value is returned.
97 *
98 * From softfloat_shortShiftRightJam64()
99 */
100static inline__inline__
101uint64_t _mesa_short_shift_right_jam64(uint64_t a, uint8_t dist)
102{
103 return a >> dist | ((a & (((uint64_t) 1 << dist) - 1)) != 0);
104}
105
106/**
107 * \brief Shifts 'a' right by the number of bits given in 'dist', which must not
108 * be zero. If any nonzero bits are shifted off, they are "jammed" into the
109 * least-significant bit of the shifted value by setting the least-significant
110 * bit to 1. This shifted-and-jammed value is returned.
111 * The value of 'dist' can be arbitrarily large. In particular, if 'dist' is
112 * greater than 64, the result will be either 0 or 1, depending on whether 'a'
113 * is zero or nonzero.
114 *
115 * From softfloat_shiftRightJam64()
116 */
117static inline__inline__
118uint64_t _mesa_shift_right_jam64(uint64_t a, uint32_t dist)
119{
120 return
121 (dist < 63) ? a >> dist | ((uint64_t) (a << (-dist & 63)) != 0) : (a != 0);
122}
123
124/**
125 * \brief Shifts 'a' right by the number of bits given in 'dist', which must not be
126 * zero. If any nonzero bits are shifted off, they are "jammed" into the
127 * least-significant bit of the shifted value by setting the least-significant
128 * bit to 1. This shifted-and-jammed value is returned.
129 * The value of 'dist' can be arbitrarily large. In particular, if 'dist' is
130 * greater than 32, the result will be either 0 or 1, depending on whether 'a'
131 * is zero or nonzero.
132 *
133 * From softfloat_shiftRightJam32()
134 */
135static inline__inline__
136uint32_t _mesa_shift_right_jam32(uint32_t a, uint16_t dist)
137{
138 return
139 (dist < 31) ? a >> dist | ((uint32_t) (a << (-dist & 31)) != 0) : (a != 0);
140}
141
142/**
143 * \brief Extracted from softfloat_roundPackToF64()
144 */
145static inline__inline__
146double _mesa_roundtozero_f64(int64_t s, int64_t e, int64_t m)
147{
148 di_type result;
149
150 if ((uint64_t) e >= 0x7fd) {
151 if (e < 0) {
152 m = _mesa_shift_right_jam64(m, -e);
153 e = 0;
154 } else if ((e > 0x7fd) || (0x8000000000000000 <= m)) {
155 e = 0x7ff;
156 m = 0;
157 result.u = (s << 63) + (e << 52) + m;
158 result.u -= 1;
159 return result.f;
160 }
161 }
162
163 m >>= 10;
164 if (m == 0)
165 e = 0;
166
167 result.u = (s << 63) + (e << 52) + m;
168 return result.f;
169}
170
171/**
172 * \brief Extracted from softfloat_roundPackToF32()
173 */
174static inline__inline__
175float _mesa_round_f32(int32_t s, int32_t e, int32_t m, bool_Bool rtz)
176{
177 fi_type result;
178 uint8_t round_increment = rtz ? 0 : 0x40;
179
180 if ((uint32_t) e >= 0xfd) {
181 if (e < 0) {
182 m = _mesa_shift_right_jam32(m, -e);
183 e = 0;
184 } else if ((e > 0xfd) || (0x80000000 <= m + round_increment)) {
185 e = 0xff;
186 m = 0;
187 result.u = (s << 31) + (e << 23) + m;
188 result.u -= !round_increment;
189 return result.f;
190 }
191 }
192
193 uint8_t round_bits;
194 round_bits = m & 0x7f;
195 m = ((uint32_t) m + round_increment) >> 7;
196 m &= ~(uint32_t) (! (round_bits ^ 0x40) & !rtz);
197 if (m == 0)
198 e = 0;
199
200 result.u = (s << 31) + (e << 23) + m;
201 return result.f;
202}
203
204/**
205 * \brief Extracted from softfloat_roundPackToF16()
206 */
207static inline__inline__
208uint16_t _mesa_roundtozero_f16(int16_t s, int16_t e, int16_t m)
209{
210 if ((uint16_t) e >= 0x1d) {
211 if (e < 0) {
212 m = _mesa_shift_right_jam32(m, -e);
213 e = 0;
214 } else if ((e > 0x1d) || (0x8000 <= m)) {
215 e = 0x1f;
216 m = 0;
217 return (s << 15) + (e << 10) + m - 1;
218 }
219 }
220
221 m >>= 4;
222 if (m == 0)
223 e = 0;
224
225 return (s << 15) + (e << 10) + m;
226}
227
228/**
229 * \brief Shifts the N-bit unsigned integer pointed to by 'a' left by the number of
230 * bits given in 'dist', where N = 'size_words' * 32. The value of 'dist'
231 * must be in the range 1 to 31. Any nonzero bits shifted off are lost. The
232 * shifted N-bit result is stored at the location pointed to by 'm_out'. Each
233 * of 'a' and 'm_out' points to a 'size_words'-long array of 32-bit elements
234 * that concatenate in the platform's normal endian order to form an N-bit
235 * integer.
236 *
237 * From softfloat_shortShiftLeftM()
238 */
239static inline__inline__ void
240_mesa_short_shift_left_m(uint8_t size_words, const uint32_t *a, uint8_t dist, uint32_t *m_out)
241{
242 uint8_t neg_dist;
243 unsigned index, last_index;
244 uint32_t part_word, a_word;
245
246 neg_dist = -dist;
247 index = index_word_hi(size_words)0;
248 last_index = index_word_lo(size_words)((size_words) - 1);
249 part_word = a[index] << dist;
250 while (index != last_index) {
251 a_word = a[index - word_incr-1];
252 m_out[index] = part_word | a_word >> (neg_dist & 31);
253 index -= word_incr-1;
254 part_word = a_word << dist;
255 }
256 m_out[index] = part_word;
257}
258
259/**
260 * \brief Shifts the N-bit unsigned integer pointed to by 'a' left by the number of
261 * bits given in 'dist', where N = 'size_words' * 32. The value of 'dist'
262 * must not be zero. Any nonzero bits shifted off are lost. The shifted
263 * N-bit result is stored at the location pointed to by 'm_out'. Each of 'a'
264 * and 'm_out' points to a 'size_words'-long array of 32-bit elements that
265 * concatenate in the platform's normal endian order to form an N-bit
266 * integer. The value of 'dist' can be arbitrarily large. In particular, if
267 * 'dist' is greater than N, the stored result will be 0.
268 *
269 * From softfloat_shiftLeftM()
270 */
271static inline__inline__ void
272_mesa_shift_left_m(uint8_t size_words, const uint32_t *a, uint32_t dist, uint32_t *m_out)
273{
274 uint32_t word_dist;
275 uint8_t inner_dist;
276 uint8_t i;
277
278 word_dist = dist >> 5;
279 if (word_dist < size_words) {
280 a += index_multiword_lo_but(size_words, word_dist)(word_dist);
281 inner_dist = dist & 31;
282 if (inner_dist) {
283 _mesa_short_shift_left_m(size_words - word_dist, a, inner_dist,
284 m_out + index_multiword_hi_but(size_words, word_dist)0);
285 if (!word_dist)
286 return;
287 } else {
288 uint32_t *dest = m_out + index_word_hi(size_words)0;
289 a += index_word_hi(size_words - word_dist)0;
290 for (i = size_words - word_dist; i; --i) {
291 *dest = *a;
292 a -= word_incr-1;
293 dest -= word_incr-1;
294 }
295 }
296 m_out += index_multiword_lo(size_words, word_dist)((size_words) - (word_dist));
297 } else {
298 word_dist = size_words;
299 }
300 do {
301 *m_out++ = 0;
302 --word_dist;
303 } while (word_dist);
304}
305
306/**
307 * \brief Shifts the N-bit unsigned integer pointed to by 'a' right by the number of
308 * bits given in 'dist', where N = 'size_words' * 32. The value of 'dist'
309 * must be in the range 1 to 31. Any nonzero bits shifted off are lost. The
310 * shifted N-bit result is stored at the location pointed to by 'm_out'. Each
311 * of 'a' and 'm_out' points to a 'size_words'-long array of 32-bit elements
312 * that concatenate in the platform's normal endian order to form an N-bit
313 * integer.
314 *
315 * From softfloat_shortShiftRightM()
316 */
317static inline__inline__ void
318_mesa_short_shift_right_m(uint8_t size_words, const uint32_t *a, uint8_t dist, uint32_t *m_out)
319{
320 uint8_t neg_dist;
321 unsigned index, last_index;
322 uint32_t part_word, a_word;
323
324 neg_dist = -dist;
325 index = index_word_lo(size_words)((size_words) - 1);
326 last_index = index_word_hi(size_words)0;
327 part_word = a[index] >> dist;
328 while (index != last_index) {
329 a_word = a[index + word_incr-1];
330 m_out[index] = a_word << (neg_dist & 31) | part_word;
331 index += word_incr-1;
332 part_word = a_word >> dist;
333 }
334 m_out[index] = part_word;
335}
336
337/**
338 * \brief Shifts the N-bit unsigned integer pointed to by 'a' right by the number of
339 * bits given in 'dist', where N = 'size_words' * 32. The value of 'dist'
340 * must be in the range 1 to 31. If any nonzero bits are shifted off, they
341 * are "jammed" into the least-significant bit of the shifted value by setting
342 * the least-significant bit to 1. This shifted-and-jammed N-bit result is
343 * stored at the location pointed to by 'm_out'. Each of 'a' and 'm_out'
344 * points to a 'size_words'-long array of 32-bit elements that concatenate in
345 * the platform's normal endian order to form an N-bit integer.
346 *
347 *
348 * From softfloat_shortShiftRightJamM()
349 */
350static inline__inline__ void
351_mesa_short_shift_right_jam_m(uint8_t size_words, const uint32_t *a, uint8_t dist, uint32_t *m_out)
352{
353 uint8_t neg_dist;
354 unsigned index, last_index;
355 uint64_t part_word, a_word;
356
357 neg_dist = -dist;
358 index = index_word_lo(size_words)((size_words) - 1);
359 last_index = index_word_hi(size_words)0;
360 a_word = a[index];
361 part_word = a_word >> dist;
362 if (part_word << dist != a_word )
363 part_word |= 1;
364 while (index != last_index) {
365 a_word = a[index + word_incr-1];
366 m_out[index] = a_word << (neg_dist & 31) | part_word;
367 index += word_incr-1;
368 part_word = a_word >> dist;
369 }
370 m_out[index] = part_word;
371}
372
373/**
374 * \brief Shifts the N-bit unsigned integer pointed to by 'a' right by the number of
375 * bits given in 'dist', where N = 'size_words' * 32. The value of 'dist'
376 * must not be zero. If any nonzero bits are shifted off, they are "jammed"
377 * into the least-significant bit of the shifted value by setting the
378 * least-significant bit to 1. This shifted-and-jammed N-bit result is stored
379 * at the location pointed to by 'm_out'. Each of 'a' and 'm_out' points to a
380 * 'size_words'-long array of 32-bit elements that concatenate in the
381 * platform's normal endian order to form an N-bit integer. The value of
382 * 'dist' can be arbitrarily large. In particular, if 'dist' is greater than
383 * N, the stored result will be either 0 or 1, depending on whether the
384 * original N bits are all zeros.
385 *
386 * From softfloat_shiftRightJamM()
387 */
388static inline__inline__ void
389_mesa_shift_right_jam_m(uint8_t size_words, const uint32_t *a, uint32_t dist, uint32_t *m_out)
390{
391 uint32_t word_jam, word_dist, *tmp;
1
'tmp' declared without an initial value
→
392 uint8_t i, inner_dist;
393
394 word_jam = 0;
395 word_dist = dist >> 5;
396 if (word_dist) {
2
←
Assuming 'word_dist' is 0
→
3
←
Taking false branch
→
397 if (size_words < word_dist)
398 word_dist = size_words;
399 tmp = (uint32_t *) (a + index_multiword_lo(size_words, word_dist)((size_words) - (word_dist)));
400 i = word_dist;
401 do {
402 word_jam = *tmp++;
403 if (word_jam)
404 break;
405 --i;
406 } while (i);
407 tmp = m_out;
408 }
409 if (word_dist < size_words) {
4
←
Assuming 'word_dist' is >= 'size_words'
→
5
←
Taking false branch
→
410 a += index_multiword_hi_but(size_words, word_dist)0;
411 inner_dist = dist & 31;
412 if (inner_dist) {
413 _mesa_short_shift_right_jam_m(size_words - word_dist, a, inner_dist,
414 m_out + index_multiword_lo_but(size_words, word_dist)(word_dist));
415 if (!word_dist) {
416 if (word_jam)
417 m_out[index_word_lo(size_words)((size_words) - 1)] |= 1;
418 return;
419 }
420 } else {
421 a += index_word_lo(size_words - word_dist)((size_words - word_dist) - 1);
422 tmp = m_out + index_word_lo(size_words)((size_words) - 1);
423 for (i = size_words - word_dist; i; --i) {
424 *tmp = *a;
425 a += word_incr-1;
426 tmp += word_incr-1;
427 }
428 }
429 tmp = m_out + index_multiword_hi(size_words, word_dist)0;
430 }
431 do {
432 *tmp++ = 0;
6
←
The expression uses uninitialized memory
433 --word_dist;
434 } while (word_dist);
435 if (word_jam)
436 m_out[index_word_lo(size_words)((size_words) - 1)] |= 1;
437}
438
439/**
440 * \brief Calculate a + b but rounding to zero.
441 *
442 * Notice that this mainly differs from the original Berkeley SoftFloat 3e
443 * implementation in that we don't really treat NaNs, Zeroes nor the
444 * signalling flags. Any NaN is good for us and the sign of the Zero is not
445 * important.
446 *
447 * From f64_add()
448 */
449double
450_mesa_double_add_rtz(double a, double b)
451{
452 const di_type a_di = {a};
453 uint64_t a_flt_m = a_di.u & 0x0fffffffffffff;
454 uint64_t a_flt_e = (a_di.u >> 52) & 0x7ff;
455 uint64_t a_flt_s = (a_di.u >> 63) & 0x1;
456 const di_type b_di = {b};
457 uint64_t b_flt_m = b_di.u & 0x0fffffffffffff;
458 uint64_t b_flt_e = (b_di.u >> 52) & 0x7ff;
459 uint64_t b_flt_s = (b_di.u >> 63) & 0x1;
460 int64_t s, e, m = 0;
461
462 s = a_flt_s;
463
464 const int64_t exp_diff = a_flt_e - b_flt_e;
465
466 /* Handle special cases */
467
468 if (a_flt_s != b_flt_s) {
469 return _mesa_double_sub_rtz(a, -b);
470 } else if ((a_flt_e == 0) && (a_flt_m == 0)) {
471 /* 'a' is zero, return 'b' */
472 return b;
473 } else if ((b_flt_e == 0) && (b_flt_m == 0)) {
474 /* 'b' is zero, return 'a' */
475 return a;
476 } else if (a_flt_e == 0x7ff && a_flt_m != 0) {
477 /* 'a' is a NaN, return NaN */
478 return a;
479 } else if (b_flt_e == 0x7ff && b_flt_m != 0) {
480 /* 'b' is a NaN, return NaN */
481 return b;
482 } else if (a_flt_e == 0x7ff && a_flt_m == 0) {
483 /* Inf + x = Inf */
484 return a;
485 } else if (b_flt_e == 0x7ff && b_flt_m == 0) {
486 /* x + Inf = Inf */
487 return b;
488 } else if (exp_diff == 0 && a_flt_e == 0) {
489 di_type result_di;
490 result_di.u = a_di.u + b_flt_m;
491 return result_di.f;
492 } else if (exp_diff == 0) {
493 e = a_flt_e;
494 m = 0x0020000000000000 + a_flt_m + b_flt_m;
495 m <<= 9;
496 } else if (exp_diff < 0) {
497 a_flt_m <<= 9;
498 b_flt_m <<= 9;
499 e = b_flt_e;
500
501 if (a_flt_e != 0)
502 a_flt_m += 0x2000000000000000;
503 else
504 a_flt_m <<= 1;
505
506 a_flt_m = _mesa_shift_right_jam64(a_flt_m, -exp_diff);
507 m = 0x2000000000000000 + a_flt_m + b_flt_m;
508 if (m < 0x4000000000000000) {
509 --e;
510 m <<= 1;
511 }
512 } else {
513 a_flt_m <<= 9;
514 b_flt_m <<= 9;
515 e = a_flt_e;
516
517 if (b_flt_e != 0)
518 b_flt_m += 0x2000000000000000;
519 else
520 b_flt_m <<= 1;
521
522 b_flt_m = _mesa_shift_right_jam64(b_flt_m, exp_diff);
523 m = 0x2000000000000000 + a_flt_m + b_flt_m;
524 if (m < 0x4000000000000000) {
525 --e;
526 m <<= 1;
527 }
528 }
529
530 return _mesa_roundtozero_f64(s, e, m);
531}
532
533/**
534 * \brief Returns the number of leading 0 bits before the most-significant 1 bit of
535 * 'a'. If 'a' is zero, 64 is returned.
536 */
537static inline__inline__ unsigned
538_mesa_count_leading_zeros64(uint64_t a)
539{
540 return 64 - util_last_bit64(a);
541}
542
543/**
544 * \brief Returns the number of leading 0 bits before the most-significant 1 bit of
545 * 'a'. If 'a' is zero, 32 is returned.
546 */
547static inline__inline__ unsigned
548_mesa_count_leading_zeros32(uint32_t a)
549{
550 return 32 - util_last_bit(a);
551}
552
553static inline__inline__ double
554_mesa_norm_round_pack_f64(int64_t s, int64_t e, int64_t m)
555{
556 int8_t shift_dist;
557
558 shift_dist = _mesa_count_leading_zeros64(m) - 1;
559 e -= shift_dist;
560 if ((10 <= shift_dist) && ((unsigned) e < 0x7fd)) {
561 di_type result;
562 result.u = (s << 63) + ((m ? e : 0) << 52) + (m << (shift_dist - 10));
563 return result.f;
564 } else {
565 return _mesa_roundtozero_f64(s, e, m << shift_dist);
566 }
567}
568
569/**
570 * \brief Replaces the N-bit unsigned integer pointed to by 'm_out' by the
571 * 2s-complement of itself, where N = 'size_words' * 32. Argument 'm_out'
572 * points to a 'size_words'-long array of 32-bit elements that concatenate in
573 * the platform's normal endian order to form an N-bit integer.
574 *
575 * From softfloat_negXM()
576 */
577static inline__inline__ void
578_mesa_neg_x_m(uint8_t size_words, uint32_t *m_out)
579{
580 unsigned index, last_index;
581 uint8_t carry;
582 uint32_t word;
583
584 index = index_word_lo(size_words)((size_words) - 1);
585 last_index = index_word_hi(size_words)0;
586 carry = 1;
587 for (;;) {
588 word = ~m_out[index] + carry;
589 m_out[index] = word;
590 if (index == last_index)
591 break;
592 index += word_incr-1;
593 if (word)
594 carry = 0;
595 }
596}
597
598/**
599 * \brief Adds the two N-bit integers pointed to by 'a' and 'b', where N =
600 * 'size_words' * 32. The addition is modulo 2^N, so any carry out is
601 * lost. The N-bit sum is stored at the location pointed to by 'm_out'. Each
602 * of 'a', 'b', and 'm_out' points to a 'size_words'-long array of 32-bit
603 * elements that concatenate in the platform's normal endian order to form an
604 * N-bit integer.
605 *
606 * From softfloat_addM()
607 */
608static inline__inline__ void
609_mesa_add_m(uint8_t size_words, const uint32_t *a, const uint32_t *b, uint32_t *m_out)
610{
611 unsigned index, last_index;
612 uint8_t carry;
613 uint32_t a_word, word;
614
615 index = index_word_lo(size_words)((size_words) - 1);
616 last_index = index_word_hi(size_words)0;
617 carry = 0;
618 for (;;) {
619 a_word = a[index];
620 word = a_word + b[index] + carry;
621 m_out[index] = word;
622 if (index == last_index)
623 break;
624 if (word != a_word)
625 carry = (word < a_word);
626 index += word_incr-1;
627 }
628}
629
630/**
631 * \brief Subtracts the two N-bit integers pointed to by 'a' and 'b', where N =
632 * 'size_words' * 32. The subtraction is modulo 2^N, so any borrow out (carry
633 * out) is lost. The N-bit difference is stored at the location pointed to by
634 * 'm_out'. Each of 'a', 'b', and 'm_out' points to a 'size_words'-long array
635 * of 32-bit elements that concatenate in the platform's normal endian order
636 * to form an N-bit integer.
637 *
638 * From softfloat_subM()
639 */
640static inline__inline__ void
641_mesa_sub_m(uint8_t size_words, const uint32_t *a, const uint32_t *b, uint32_t *m_out)
642{
643 unsigned index, last_index;
644 uint8_t borrow;
645 uint32_t a_word, b_word;
646
647 index = index_word_lo(size_words)((size_words) - 1);
648 last_index = index_word_hi(size_words)0;
649 borrow = 0;
650 for (;;) {
651 a_word = a[index];
652 b_word = b[index];
653 m_out[index] = a_word - b_word - borrow;
654 if (index == last_index)
655 break;
656 borrow = borrow ? (a_word <= b_word) : (a_word < b_word);
657 index += word_incr-1;
658 }
659}
660
661/* Calculate a - b but rounding to zero.
662 *
663 * Notice that this mainly differs from the original Berkeley SoftFloat 3e
664 * implementation in that we don't really treat NaNs, Zeroes nor the
665 * signalling flags. Any NaN is good for us and the sign of the Zero is not
666 * important.
667 *
668 * From f64_sub()
669 */
670double
671_mesa_double_sub_rtz(double a, double b)
672{
673 const di_type a_di = {a};
674 uint64_t a_flt_m = a_di.u & 0x0fffffffffffff;
675 uint64_t a_flt_e = (a_di.u >> 52) & 0x7ff;
676 uint64_t a_flt_s = (a_di.u >> 63) & 0x1;
677 const di_type b_di = {b};
678 uint64_t b_flt_m = b_di.u & 0x0fffffffffffff;
679 uint64_t b_flt_e = (b_di.u >> 52) & 0x7ff;
680 uint64_t b_flt_s = (b_di.u >> 63) & 0x1;
681 int64_t s, e, m = 0;
682 int64_t m_diff = 0;
683 unsigned shift_dist = 0;
684
685 s = a_flt_s;
686
687 const int64_t exp_diff = a_flt_e - b_flt_e;
688
689 /* Handle special cases */
690
691 if (a_flt_s != b_flt_s) {
692 return _mesa_double_add_rtz(a, -b);
693 } else if ((a_flt_e == 0) && (a_flt_m == 0)) {
694 /* 'a' is zero, return '-b' */
695 return -b;
696 } else if ((b_flt_e == 0) && (b_flt_m == 0)) {
697 /* 'b' is zero, return 'a' */
698 return a;
699 } else if (a_flt_e == 0x7ff && a_flt_m != 0) {
700 /* 'a' is a NaN, return NaN */
701 return a;
702 } else if (b_flt_e == 0x7ff && b_flt_m != 0) {
703 /* 'b' is a NaN, return NaN */
704 return b;
705 } else if (a_flt_e == 0x7ff && a_flt_m == 0) {
706 if (b_flt_e == 0x7ff && b_flt_m == 0) {
707 /* Inf - Inf = NaN */
708 di_type result;
709 e = 0x7ff;
710 result.u = (s << 63) + (e << 52) + 0x1;
711 return result.f;
712 }
713 /* Inf - x = Inf */
714 return a;
715 } else if (b_flt_e == 0x7ff && b_flt_m == 0) {
716 /* x - Inf = -Inf */
717 return -b;
718 } else if (exp_diff == 0) {
719 m_diff = a_flt_m - b_flt_m;
720
721 if (m_diff == 0)
722 return 0;
723 if (a_flt_e)
724 --a_flt_e;
725 if (m_diff < 0) {
726 s = !s;
727 m_diff = -m_diff;
728 }
729
730 shift_dist = _mesa_count_leading_zeros64(m_diff) - 11;
731 e = a_flt_e - shift_dist;
732 if (e < 0) {
733 shift_dist = a_flt_e;
734 e = 0;
735 }
736
737 di_type result;
738 result.u = (s << 63) + (e << 52) + (m_diff << shift_dist);
739 return result.f;
740 } else if (exp_diff < 0) {
741 a_flt_m <<= 10;
742 b_flt_m <<= 10;
743 s = !s;
744
745 a_flt_m += (a_flt_e) ? 0x4000000000000000 : a_flt_m;
746 a_flt_m = _mesa_shift_right_jam64(a_flt_m, -exp_diff);
747 b_flt_m |= 0x4000000000000000;
748 e = b_flt_e;
749 m = b_flt_m - a_flt_m;
750 } else {
751 a_flt_m <<= 10;
752 b_flt_m <<= 10;
753
754 b_flt_m += (b_flt_e) ? 0x4000000000000000 : b_flt_m;
755 b_flt_m = _mesa_shift_right_jam64(b_flt_m, exp_diff);
756 a_flt_m |= 0x4000000000000000;
757 e = a_flt_e;
758 m = a_flt_m - b_flt_m;
759 }
760
761 return _mesa_norm_round_pack_f64(s, e - 1, m);
762}
763
764static inline__inline__ void
765_mesa_norm_subnormal_mantissa_f64(uint64_t m, uint64_t *exp, uint64_t *m_out)
766{
767 int shift_dist;
768
769 shift_dist = _mesa_count_leading_zeros64(m) - 11;
770 *exp = 1 - shift_dist;
771 *m_out = m << shift_dist;
772}
773
774static inline__inline__ void
775_mesa_norm_subnormal_mantissa_f32(uint32_t m, uint32_t *exp, uint32_t *m_out)
776{
777 int shift_dist;
778
779 shift_dist = _mesa_count_leading_zeros32(m) - 8;
780 *exp = 1 - shift_dist;
781 *m_out = m << shift_dist;
782}
783
784/**
785 * \brief Multiplies 'a' and 'b' and stores the 128-bit product at the location
786 * pointed to by 'zPtr'. Argument 'zPtr' points to an array of four 32-bit
787 * elements that concatenate in the platform's normal endian order to form a
788 * 128-bit integer.
789 *
790 * From softfloat_mul64To128M()
791 */
792static inline__inline__ void
793_mesa_softfloat_mul_f64_to_f128_m(uint64_t a, uint64_t b, uint32_t *m_out)
794{
795 uint32_t a32, a0, b32, b0;
796 uint64_t z0, mid1, z64, mid;
797
798 a32 = a >> 32;
799 a0 = a;
800 b32 = b >> 32;
801 b0 = b;
802 z0 = (uint64_t) a0 * b0;
803 mid1 = (uint64_t) a32 * b0;
804 mid = mid1 + (uint64_t) a0 * b32;
805 z64 = (uint64_t) a32 * b32;
806 z64 += (uint64_t) (mid < mid1) << 32 | mid >> 32;
807 mid <<= 32;
808 z0 += mid;
809 m_out[index_word(4, 1)((4) - 1 - (1))] = z0 >> 32;
810 m_out[index_word(4, 0)((4) - 1 - (0))] = z0;
811 z64 += (z0 < mid);
812 m_out[index_word(4, 3)((4) - 1 - (3))] = z64 >> 32;
813 m_out[index_word(4, 2)((4) - 1 - (2))] = z64;
814}
815
816/* Calculate a * b but rounding to zero.
817 *
818 * Notice that this mainly differs from the original Berkeley SoftFloat 3e
819 * implementation in that we don't really treat NaNs, Zeroes nor the
820 * signalling flags. Any NaN is good for us and the sign of the Zero is not
821 * important.
822 *
823 * From f64_mul()
824 */
825double
826_mesa_double_mul_rtz(double a, double b)
827{
828 const di_type a_di = {a};
829 uint64_t a_flt_m = a_di.u & 0x0fffffffffffff;
830 uint64_t a_flt_e = (a_di.u >> 52) & 0x7ff;
831 uint64_t a_flt_s = (a_di.u >> 63) & 0x1;
832 const di_type b_di = {b};
833 uint64_t b_flt_m = b_di.u & 0x0fffffffffffff;
834 uint64_t b_flt_e = (b_di.u >> 52) & 0x7ff;
835 uint64_t b_flt_s = (b_di.u >> 63) & 0x1;
836 int64_t s, e, m = 0;
837
838 s = a_flt_s ^ b_flt_s;
839
840 if (a_flt_e == 0x7ff) {
841 if (a_flt_m != 0) {
842 /* 'a' is a NaN, return NaN */
843 return a;
844 } else if (b_flt_e == 0x7ff && b_flt_m != 0) {
845 /* 'b' is a NaN, return NaN */
846 return b;
847 }
848
849 if (!(b_flt_e | b_flt_m)) {
850 /* Inf * 0 = NaN */
851 di_type result;
852 e = 0x7ff;
853 result.u = (s << 63) + (e << 52) + 0x1;
854 return result.f;
855 }
856 /* Inf * x = Inf */
857 di_type result;
858 e = 0x7ff;
859 result.u = (s << 63) + (e << 52) + 0;
860 return result.f;
861 }
862
863 if (b_flt_e == 0x7ff) {
864 if (b_flt_m != 0) {
865 /* 'b' is a NaN, return NaN */
866 return b;
867 }
868 if (!(a_flt_e | a_flt_m)) {
869 /* 0 * Inf = NaN */
870 di_type result;
871 e = 0x7ff;
872 result.u = (s << 63) + (e << 52) + 0x1;
873 return result.f;
874 }
875 /* x * Inf = Inf */
876 di_type result;
877 e = 0x7ff;
878 result.u = (s << 63) + (e << 52) + 0;
879 return result.f;
880 }
881
882 if (a_flt_e == 0) {
883 if (a_flt_m == 0) {
884 /* 'a' is zero. Return zero */
885 di_type result;
886 result.u = (s << 63) + 0;
887 return result.f;
888 }
889 _mesa_norm_subnormal_mantissa_f64(a_flt_m , &a_flt_e, &a_flt_m);
890 }
891 if (b_flt_e == 0) {
892 if (b_flt_m == 0) {
893 /* 'b' is zero. Return zero */
894 di_type result;
895 result.u = (s << 63) + 0;
896 return result.f;
897 }
898 _mesa_norm_subnormal_mantissa_f64(b_flt_m , &b_flt_e, &b_flt_m);
899 }
900
901 e = a_flt_e + b_flt_e - 0x3ff;
902 a_flt_m = (a_flt_m | 0x0010000000000000) << 10;
903 b_flt_m = (b_flt_m | 0x0010000000000000) << 11;
904
905 uint32_t m_128[4];
906 _mesa_softfloat_mul_f64_to_f128_m(a_flt_m, b_flt_m, m_128);
907
908 m = (uint64_t) m_128[index_word(4, 3)((4) - 1 - (3))] << 32 | m_128[index_word(4, 2)((4) - 1 - (2))];
909 if (m_128[index_word(4, 1)((4) - 1 - (1))] || m_128[index_word(4, 0)((4) - 1 - (0))])
910 m |= 1;
911
912 if (m < 0x4000000000000000) {
913 --e;
914 m <<= 1;
915 }
916
917 return _mesa_roundtozero_f64(s, e, m);
918}
919
920
921/**
922 * \brief Calculate a * b + c but rounding to zero.
923 *
924 * Notice that this mainly differs from the original Berkeley SoftFloat 3e
925 * implementation in that we don't really treat NaNs, Zeroes nor the
926 * signalling flags. Any NaN is good for us and the sign of the Zero is not
927 * important.
928 *
929 * From f64_mulAdd()
930 */
931double
932_mesa_double_fma_rtz(double a, double b, double c)
933{
934 const di_type a_di = {a};
935 uint64_t a_flt_m = a_di.u & 0x0fffffffffffff;
936 uint64_t a_flt_e = (a_di.u >> 52) & 0x7ff;
937 uint64_t a_flt_s = (a_di.u >> 63) & 0x1;
938 const di_type b_di = {b};
939 uint64_t b_flt_m = b_di.u & 0x0fffffffffffff;
940 uint64_t b_flt_e = (b_di.u >> 52) & 0x7ff;
941 uint64_t b_flt_s = (b_di.u >> 63) & 0x1;
942 const di_type c_di = {c};
943 uint64_t c_flt_m = c_di.u & 0x0fffffffffffff;
944 uint64_t c_flt_e = (c_di.u >> 52) & 0x7ff;
945 uint64_t c_flt_s = (c_di.u >> 63) & 0x1;
946 int64_t s, e, m = 0;
947
948 c_flt_s ^= 0;
949 s = a_flt_s ^ b_flt_s ^ 0;
950
951 if (a_flt_e == 0x7ff) {
952 if (a_flt_m != 0) {
953 /* 'a' is a NaN, return NaN */
954 return a;
955 } else if (b_flt_e == 0x7ff && b_flt_m != 0) {
956 /* 'b' is a NaN, return NaN */
957 return b;
958 } else if (c_flt_e == 0x7ff && c_flt_m != 0) {
959 /* 'c' is a NaN, return NaN */
960 return c;
961 }
962
963 if (!(b_flt_e | b_flt_m)) {
964 /* Inf * 0 + y = NaN */
965 di_type result;
966 e = 0x7ff;
967 result.u = (s << 63) + (e << 52) + 0x1;
968 return result.f;
969 }
970
971 if ((c_flt_e == 0x7ff && c_flt_m == 0) && (s != c_flt_s)) {
972 /* Inf * x - Inf = NaN */
973 di_type result;
974 e = 0x7ff;
975 result.u = (s << 63) + (e << 52) + 0x1;
976 return result.f;
977 }
978
979 /* Inf * x + y = Inf */
980 di_type result;
981 e = 0x7ff;
982 result.u = (s << 63) + (e << 52) + 0;
983 return result.f;
984 }
985
986 if (b_flt_e == 0x7ff) {
987 if (b_flt_m != 0) {
988 /* 'b' is a NaN, return NaN */
989 return b;
990 } else if (c_flt_e == 0x7ff && c_flt_m != 0) {
991 /* 'c' is a NaN, return NaN */
992 return c;
993 }
994
995 if (!(a_flt_e | a_flt_m)) {
996 /* 0 * Inf + y = NaN */
997 di_type result;
998 e = 0x7ff;
999 result.u = (s << 63) + (e << 52) + 0x1;
1000 return result.f;
1001 }
1002
1003 if ((c_flt_e == 0x7ff && c_flt_m == 0) && (s != c_flt_s)) {
1004 /* x * Inf - Inf = NaN */
1005 di_type result;
1006 e = 0x7ff;
1007 result.u = (s << 63) + (e << 52) + 0x1;
1008 return result.f;
1009 }
1010
1011 /* x * Inf + y = Inf */
1012 di_type result;
1013 e = 0x7ff;
1014 result.u = (s << 63) + (e << 52) + 0;
1015 return result.f;
1016 }
1017
1018 if (c_flt_e == 0x7ff) {
1019 if (c_flt_m != 0) {
1020 /* 'c' is a NaN, return NaN */
1021 return c;
1022 }
1023
1024 /* x * y + Inf = Inf */
1025 return c;
1026 }
1027
1028 if (a_flt_e == 0) {
1029 if (a_flt_m == 0) {
1030 /* 'a' is zero, return 'c' */
1031 return c;
1032 }
1033 _mesa_norm_subnormal_mantissa_f64(a_flt_m , &a_flt_e, &a_flt_m);
1034 }
1035
1036 if (b_flt_e == 0) {
1037 if (b_flt_m == 0) {
1038 /* 'b' is zero, return 'c' */
1039 return c;
1040 }
1041 _mesa_norm_subnormal_mantissa_f64(b_flt_m , &b_flt_e, &b_flt_m);
1042 }
1043
1044 e = a_flt_e + b_flt_e - 0x3fe;
1045 a_flt_m = (a_flt_m | 0x0010000000000000) << 10;
1046 b_flt_m = (b_flt_m | 0x0010000000000000) << 11;
1047
1048 uint32_t m_128[4];
1049 _mesa_softfloat_mul_f64_to_f128_m(a_flt_m, b_flt_m, m_128);
1050
1051 m = (uint64_t) m_128[index_word(4, 3)((4) - 1 - (3))] << 32 | m_128[index_word(4, 2)((4) - 1 - (2))];
1052
1053 int64_t shift_dist = 0;
1054 if (!(m & 0x4000000000000000)) {
1055 --e;
1056 shift_dist = -1;
1057 }
1058
1059 if (c_flt_e == 0) {
1060 if (c_flt_m == 0) {
1061 /* 'c' is zero, return 'a * b' */
1062 if (shift_dist)
1063 m <<= 1;
1064
1065 if (m_128[index_word(4, 1)((4) - 1 - (1))] || m_128[index_word(4, 0)((4) - 1 - (0))])
1066 m |= 1;
1067 return _mesa_roundtozero_f64(s, e - 1, m);
1068 }
1069 _mesa_norm_subnormal_mantissa_f64(c_flt_m , &c_flt_e, &c_flt_m);
1070 }
1071 c_flt_m = (c_flt_m | 0x0010000000000000) << 10;
1072
1073 uint32_t c_flt_m_128[4];
1074 int64_t exp_diff = e - c_flt_e;
1075 if (exp_diff < 0) {
1076 e = c_flt_e;
1077 if ((s == c_flt_s) || (exp_diff < -1)) {
1078 shift_dist -= exp_diff;
1079 if (shift_dist) {
1080 m = _mesa_shift_right_jam64(m, shift_dist);
1081 }
1082 } else {
1083 if (!shift_dist) {
1084 _mesa_short_shift_right_m(4, m_128, 1, m_128);
1085 }
1086 }
1087 } else {
1088 if (shift_dist)
1089 _mesa_add_m(4, m_128, m_128, m_128);
1090 if (!exp_diff) {
1091 m = (uint64_t) m_128[index_word(4, 3)((4) - 1 - (3))] << 32
1092 | m_128[index_word(4, 2)((4) - 1 - (2))];
1093 } else {
1094 c_flt_m_128[index_word(4, 3)((4) - 1 - (3))] = c_flt_m >> 32;
1095 c_flt_m_128[index_word(4, 2)((4) - 1 - (2))] = c_flt_m;
1096 c_flt_m_128[index_word(4, 1)((4) - 1 - (1))] = 0;
1097 c_flt_m_128[index_word(4, 0)((4) - 1 - (0))] = 0;
1098 _mesa_shift_right_jam_m(4, c_flt_m_128, exp_diff, c_flt_m_128);
1099 }
1100 }
1101
1102 if (s == c_flt_s) {
1103 if (exp_diff <= 0) {
1104 m += c_flt_m;
1105 } else {
1106 _mesa_add_m(4, m_128, c_flt_m_128, m_128);
1107 m = (uint64_t) m_128[index_word(4, 3)((4) - 1 - (3))] << 32
1108 | m_128[index_word(4, 2)((4) - 1 - (2))];
1109 }
1110 if (m & 0x8000000000000000) {
1111 e++;
1112 m = _mesa_short_shift_right_jam64(m, 1);
1113 }
1114 } else {
1115 if (exp_diff < 0) {
1116 s = c_flt_s;
1117 if (exp_diff < -1) {
1118 m = c_flt_m - m;
1119 if (m_128[index_word(4, 1)((4) - 1 - (1))] || m_128[index_word(4, 0)((4) - 1 - (0))]) {
1120 m = (m - 1) | 1;
1121 }
1122 if (!(m & 0x4000000000000000)) {
1123 --e;
1124 m <<= 1;
1125 }
1126 return _mesa_roundtozero_f64(s, e - 1, m);
1127 } else {
1128 c_flt_m_128[index_word(4, 3)((4) - 1 - (3))] = c_flt_m >> 32;
1129 c_flt_m_128[index_word(4, 2)((4) - 1 - (2))] = c_flt_m;
1130 c_flt_m_128[index_word(4, 1)((4) - 1 - (1))] = 0;
1131 c_flt_m_128[index_word(4, 0)((4) - 1 - (0))] = 0;
1132 _mesa_sub_m(4, c_flt_m_128, m_128, m_128);
1133 }
1134 } else if (!exp_diff) {
1135 m -= c_flt_m;
1136 if (!m && !m_128[index_word(4, 1)((4) - 1 - (1))] && !m_128[index_word(4, 0)((4) - 1 - (0))]) {
1137 /* Return zero */
1138 di_type result;
1139 result.u = (s << 63) + 0;
1140 return result.f;
1141 }
1142 m_128[index_word(4, 3)((4) - 1 - (3))] = m >> 32;
1143 m_128[index_word(4, 2)((4) - 1 - (2))] = m;
1144 if (m & 0x8000000000000000) {
1145 s = !s;
1146 _mesa_neg_x_m(4, m_128);
1147 }
1148 } else {
1149 _mesa_sub_m(4, m_128, c_flt_m_128, m_128);
1150 if (1 < exp_diff) {
1151 m = (uint64_t) m_128[index_word(4, 3)((4) - 1 - (3))] << 32
1152 | m_128[index_word(4, 2)((4) - 1 - (2))];
1153 if (!(m & 0x4000000000000000)) {
1154 --e;
1155 m <<= 1;
1156 }
1157 if (m_128[index_word(4, 1)((4) - 1 - (1))] || m_128[index_word(4, 0)((4) - 1 - (0))])
1158 m |= 1;
1159 return _mesa_roundtozero_f64(s, e - 1, m);
1160 }
1161 }
1162
1163 shift_dist = 0;
1164 m = (uint64_t) m_128[index_word(4, 3)((4) - 1 - (3))] << 32
1165 | m_128[index_word(4, 2)((4) - 1 - (2))];
1166 if (!m) {
1167 shift_dist = 64;
1168 m = (uint64_t) m_128[index_word(4, 1)((4) - 1 - (1))] << 32
1169 | m_128[index_word(4, 0)((4) - 1 - (0))];
1170 }
1171 shift_dist += _mesa_count_leading_zeros64(m) - 1;
1172 if (shift_dist) {
1173 e -= shift_dist;
1174 _mesa_shift_left_m(4, m_128, shift_dist, m_128);
1175 m = (uint64_t) m_128[index_word(4, 3)((4) - 1 - (3))] << 32
1176 | m_128[index_word(4, 2)((4) - 1 - (2))];
1177 }
1178 }
1179
1180 if (m_128[index_word(4, 1)((4) - 1 - (1))] || m_128[index_word(4, 0)((4) - 1 - (0))])
1181 m |= 1;
1182 return _mesa_roundtozero_f64(s, e - 1, m);
1183}
1184
1185
1186/**
1187 * \brief Calculate a * b + c but rounding to zero.
1188 *
1189 * Notice that this mainly differs from the original Berkeley SoftFloat 3e
1190 * implementation in that we don't really treat NaNs, Zeroes nor the
1191 * signalling flags. Any NaN is good for us and the sign of the Zero is not
1192 * important.
1193 *
1194 * From f32_mulAdd()
1195 */
1196float
1197_mesa_float_fma_rtz(float a, float b, float c)
1198{
1199 const fi_type a_fi = {a};
1200 uint32_t a_flt_m = a_fi.u & 0x07fffff;
1201 uint32_t a_flt_e = (a_fi.u >> 23) & 0xff;
1202 uint32_t a_flt_s = (a_fi.u >> 31) & 0x1;
1203 const fi_type b_fi = {b};
1204 uint32_t b_flt_m = b_fi.u & 0x07fffff;
1205 uint32_t b_flt_e = (b_fi.u >> 23) & 0xff;
1206 uint32_t b_flt_s = (b_fi.u >> 31) & 0x1;
1207 const fi_type c_fi = {c};
1208 uint32_t c_flt_m = c_fi.u & 0x07fffff;
1209 uint32_t c_flt_e = (c_fi.u >> 23) & 0xff;
1210 uint32_t c_flt_s = (c_fi.u >> 31) & 0x1;
1211 int32_t s, e, m = 0;
1212
1213 c_flt_s ^= 0;
1214 s = a_flt_s ^ b_flt_s ^ 0;
1215
1216 if (a_flt_e == 0xff) {
1217 if (a_flt_m != 0) {
1218 /* 'a' is a NaN, return NaN */
1219 return a;
1220 } else if (b_flt_e == 0xff && b_flt_m != 0) {
1221 /* 'b' is a NaN, return NaN */
1222 return b;
1223 } else if (c_flt_e == 0xff && c_flt_m != 0) {
1224 /* 'c' is a NaN, return NaN */
1225 return c;
1226 }
1227
1228 if (!(b_flt_e | b_flt_m)) {
1229 /* Inf * 0 + y = NaN */
1230 fi_type result;
1231 e = 0xff;
1232 result.u = (s << 31) + (e << 23) + 0x1;
1233 return result.f;
1234 }
1235
1236 if ((c_flt_e == 0xff && c_flt_m == 0) && (s != c_flt_s)) {
1237 /* Inf * x - Inf = NaN */
1238 fi_type result;
1239 e = 0xff;
1240 result.u = (s << 31) + (e << 23) + 0x1;
1241 return result.f;
1242 }
1243
1244 /* Inf * x + y = Inf */
1245 fi_type result;
1246 e = 0xff;
1247 result.u = (s << 31) + (e << 23) + 0;
1248 return result.f;
1249 }
1250
1251 if (b_flt_e == 0xff) {
1252 if (b_flt_m != 0) {
1253 /* 'b' is a NaN, return NaN */
1254 return b;
1255 } else if (c_flt_e == 0xff && c_flt_m != 0) {
1256 /* 'c' is a NaN, return NaN */
1257 return c;
1258 }
1259
1260 if (!(a_flt_e | a_flt_m)) {
1261 /* 0 * Inf + y = NaN */
1262 fi_type result;
1263 e = 0xff;
1264 result.u = (s << 31) + (e << 23) + 0x1;
1265 return result.f;
1266 }
1267
1268 if ((c_flt_e == 0xff && c_flt_m == 0) && (s != c_flt_s)) {
1269 /* x * Inf - Inf = NaN */
1270 fi_type result;
1271 e = 0xff;
1272 result.u = (s << 31) + (e << 23) + 0x1;
1273 return result.f;
1274 }
1275
1276 /* x * Inf + y = Inf */
1277 fi_type result;
1278 e = 0xff;
1279 result.u = (s << 31) + (e << 23) + 0;
1280 return result.f;
1281 }
1282
1283 if (c_flt_e == 0xff) {
1284 if (c_flt_m != 0) {
1285 /* 'c' is a NaN, return NaN */
1286 return c;
1287 }
1288
1289 /* x * y + Inf = Inf */
1290 return c;
1291 }
1292
1293 if (a_flt_e == 0) {
1294 if (a_flt_m == 0) {
1295 /* 'a' is zero, return 'c' */
1296 return c;
1297 }
1298 _mesa_norm_subnormal_mantissa_f32(a_flt_m , &a_flt_e, &a_flt_m);
1299 }
1300
1301 if (b_flt_e == 0) {
1302 if (b_flt_m == 0) {
1303 /* 'b' is zero, return 'c' */
1304 return c;
1305 }
1306 _mesa_norm_subnormal_mantissa_f32(b_flt_m , &b_flt_e, &b_flt_m);
1307 }
1308
1309 e = a_flt_e + b_flt_e - 0x7e;
1310 a_flt_m = (a_flt_m | 0x00800000) << 7;
1311 b_flt_m = (b_flt_m | 0x00800000) << 7;
1312
1313 uint64_t m_64 = (uint64_t) a_flt_m * b_flt_m;
1314 if (m_64 < 0x2000000000000000) {
1315 --e;
1316 m_64 <<= 1;
1317 }
1318
1319 if (c_flt_e == 0) {
1320 if (c_flt_m == 0) {
1321 /* 'c' is zero, return 'a * b' */
1322 m = _mesa_short_shift_right_jam64(m_64, 31);
1323 return _mesa_round_f32(s, e - 1, m, true1);
1324 }
1325 _mesa_norm_subnormal_mantissa_f32(c_flt_m , &c_flt_e, &c_flt_m);
1326 }
1327 c_flt_m = (c_flt_m | 0x00800000) << 6;
1328
1329 int16_t exp_diff = e - c_flt_e;
1330 if (s == c_flt_s) {
1331 if (exp_diff <= 0) {
1332 e = c_flt_e;
1333 m = c_flt_m + _mesa_shift_right_jam64(m_64, 32 - exp_diff);
1334 } else {
1335 m_64 += _mesa_shift_right_jam64((uint64_t) c_flt_m << 32, exp_diff);
1336 m = _mesa_short_shift_right_jam64(m_64, 32);
1337 }
1338 if (m < 0x40000000) {
1339 --e;
1340 m <<= 1;
1341 }
1342 } else {
1343 uint64_t c_flt_m_64 = (uint64_t) c_flt_m << 32;
1344 if (exp_diff < 0) {
1345 s = c_flt_s;
1346 e = c_flt_e;
1347 m_64 = c_flt_m_64 - _mesa_shift_right_jam64(m_64, -exp_diff);
1348 } else if (!exp_diff) {
1349 m_64 -= c_flt_m_64;
1350 if (!m_64) {
1351 /* Return zero */
1352 fi_type result;
1353 result.u = (s << 31) + 0;
1354 return result.f;
1355 }
1356 if (m_64 & 0x8000000000000000) {
1357 s = !s;
1358 m_64 = -m_64;
1359 }
1360 } else {
1361 m_64 -= _mesa_shift_right_jam64(c_flt_m_64, exp_diff);
1362 }
1363 int8_t shift_dist = _mesa_count_leading_zeros64(m_64) - 1;
1364 e -= shift_dist;
1365 shift_dist -= 32;
1366 if (shift_dist < 0) {
1367 m = _mesa_short_shift_right_jam64(m_64, -shift_dist);
1368 } else {
1369 m = (uint32_t) m_64 << shift_dist;
1370 }
1371 }
1372
1373 return _mesa_round_f32(s, e, m, true1);
1374}
1375
1376
1377/**
1378 * \brief Converts from 64bits to 32bits float and rounds according to
1379 * instructed.
1380 *
1381 * From f64_to_f32()
1382 */
1383float
1384_mesa_double_to_f32(double val, bool_Bool rtz)
1385{
1386 const di_type di = {val};
1387 uint64_t flt_m = di.u & 0x0fffffffffffff;
1388 uint64_t flt_e = (di.u >> 52) & 0x7ff;
1389 uint64_t flt_s = (di.u >> 63) & 0x1;
1390 int32_t s, e, m = 0;
1391
1392 s = flt_s;
1393
1394 if (flt_e == 0x7ff) {
1395 if (flt_m != 0) {
1396 /* 'val' is a NaN, return NaN */
1397 fi_type result;
1398 e = 0xff;
1399 m = 0x1;
1400 result.u = (s << 31) + (e << 23) + m;
1401 return result.f;
1402 }
1403
1404 /* 'val' is Inf, return Inf */
1405 fi_type result;
1406 e = 0xff;
1407 result.u = (s << 31) + (e << 23) + m;
1408 return result.f;
1409 }
1410
1411 if (!(flt_e | flt_m)) {
1412 /* 'val' is zero, return zero */
1413 fi_type result;
1414 e = 0;
1415 result.u = (s << 31) + (e << 23) + m;
1416 return result.f;
1417 }
1418
1419 m = _mesa_short_shift_right_jam64(flt_m, 22);
1420 if ( ! (flt_e | m) ) {
1421 /* 'val' is denorm, return zero */
1422 fi_type result;
1423 e = 0;
1424 result.u = (s << 31) + (e << 23) + m;
1425 return result.f;
1426 }
1427
1428 return _mesa_round_f32(s, flt_e - 0x381, m | 0x40000000, rtz);
1429}
1430
1431
1432/**
1433 * \brief Converts from 32bits to 16bits float and rounds the result to zero.
1434 *
1435 * From f32_to_f16()
1436 */
1437uint16_t
1438_mesa_float_to_half_rtz(float val)
1439{
1440 const fi_type fi = {val};
1441 const uint32_t flt_m = fi.u & 0x7fffff;
1442 const uint32_t flt_e = (fi.u >> 23) & 0xff;
1443 const uint32_t flt_s = (fi.u >> 31) & 0x1;
1444 int16_t s, e, m = 0;
1445
1446 s = flt_s;
1447
1448 if (flt_e == 0xff) {
1449 if (flt_m != 0) {
1450 /* 'val' is a NaN, return NaN */
1451 e = 0x1f;
1452 m = 0x1;
1453 return (s << 15) + (e << 10) + m;
1454 }
1455
1456 /* 'val' is Inf, return Inf */
1457 e = 0x1f;
1458 return (s << 15) + (e << 10) + m;
1459 }
1460
1461 if (!(flt_e | flt_m)) {
1462 /* 'val' is zero, return zero */
1463 e = 0;
1464 return (s << 15) + (e << 10) + m;
1465 }
1466
1467 m = flt_m >> 9 | ((flt_m & 0x1ff) != 0);
1468 if ( ! (flt_e | m) ) {
1469 /* 'val' is denorm, return zero */
1470 e = 0;
1471 return (s << 15) + (e << 10) + m;
1472 }
1473
1474 return _mesa_roundtozero_f16(s, flt_e - 0x71, m | 0x4000);
1475}