--- /dev/null
+/* Correctly-rounded cosine of binary32 value for angles in half-revolutions
+
+Copyright (c) 2022-2025 Alexei Sibidanov.
+
+The original version of this file was copied from the CORE-MATH
+project (src/binary32/cospi/cospif.c, revision f786e13).
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+*/
+
+#include <math.h>
+#include <stdint.h>
+#include <libm-alias-float.h>
+#include "math_config.h"
+
+float
+__cospif (float x)
+{
+ static const double sn[] =
+ {
+ 0x1.921fb54442d0fp-37, -0x1.4abbce6102b94p-112, 0x1.4669fa3c58463p-189
+ };
+ static const double cn[] =
+ {
+ -0x1.3bd3cc9be45cfp-74, 0x1.03c1f08088742p-150, -0x1.55d1e5eff55a5p-228
+ };
+ /* S[i] approximates sin(i*pi/2^6) */
+ static const double S[] =
+ {
+ 0x0p+0, 0x1.91f65f10dd814p-5, 0x1.917a6bc29b42cp-4,
+ 0x1.2c8106e8e613ap-3, 0x1.8f8b83c69a60bp-3, 0x1.f19f97b215f1bp-3,
+ 0x1.294062ed59f06p-2, 0x1.58f9a75ab1fddp-2, 0x1.87de2a6aea963p-2,
+ 0x1.b5d1009e15ccp-2, 0x1.e2b5d3806f63bp-2, 0x1.073879922ffeep-1,
+ 0x1.1c73b39ae68c8p-1, 0x1.30ff7fce17035p-1, 0x1.44cf325091dd6p-1,
+ 0x1.57d69348cecap-1, 0x1.6a09e667f3bcdp-1, 0x1.7b5df226aafafp-1,
+ 0x1.8bc806b151741p-1, 0x1.9b3e047f38741p-1, 0x1.a9b66290ea1a3p-1,
+ 0x1.b728345196e3ep-1, 0x1.c38b2f180bdb1p-1, 0x1.ced7af43cc773p-1,
+ 0x1.d906bcf328d46p-1, 0x1.e212104f686e5p-1, 0x1.e9f4156c62ddap-1,
+ 0x1.f0a7efb9230d7p-1, 0x1.f6297cff75cbp-1, 0x1.fa7557f08a517p-1,
+ 0x1.fd88da3d12526p-1, 0x1.ff621e3796d7ep-1, 0x1p+0,
+ 0x1.ff621e3796d7ep-1, 0x1.fd88da3d12526p-1, 0x1.fa7557f08a517p-1,
+ 0x1.f6297cff75cbp-1, 0x1.f0a7efb9230d7p-1, 0x1.e9f4156c62ddap-1,
+ 0x1.e212104f686e5p-1, 0x1.d906bcf328d46p-1, 0x1.ced7af43cc773p-1,
+ 0x1.c38b2f180bdb1p-1, 0x1.b728345196e3ep-1, 0x1.a9b66290ea1a3p-1,
+ 0x1.9b3e047f38741p-1, 0x1.8bc806b151741p-1, 0x1.7b5df226aafafp-1,
+ 0x1.6a09e667f3bcdp-1, 0x1.57d69348cecap-1, 0x1.44cf325091dd6p-1,
+ 0x1.30ff7fce17035p-1, 0x1.1c73b39ae68c8p-1, 0x1.073879922ffeep-1,
+ 0x1.e2b5d3806f63bp-2, 0x1.b5d1009e15ccp-2, 0x1.87de2a6aea963p-2,
+ 0x1.58f9a75ab1fddp-2, 0x1.294062ed59f06p-2, 0x1.f19f97b215f1bp-3,
+ 0x1.8f8b83c69a60bp-3, 0x1.2c8106e8e613ap-3, 0x1.917a6bc29b42cp-4,
+ 0x1.91f65f10dd814p-5, 0x0p+0, -0x1.91f65f10dd814p-5,
+ -0x1.917a6bc29b42cp-4, -0x1.2c8106e8e613ap-3, -0x1.8f8b83c69a60bp-3,
+ -0x1.f19f97b215f1bp-3, -0x1.294062ed59f06p-2, -0x1.58f9a75ab1fddp-2,
+ -0x1.87de2a6aea963p-2, -0x1.b5d1009e15ccp-2, -0x1.e2b5d3806f63bp-2,
+ -0x1.073879922ffeep-1, -0x1.1c73b39ae68c8p-1, -0x1.30ff7fce17035p-1,
+ -0x1.44cf325091dd6p-1, -0x1.57d69348cecap-1, -0x1.6a09e667f3bcdp-1,
+ -0x1.7b5df226aafafp-1, -0x1.8bc806b151741p-1, -0x1.9b3e047f38741p-1,
+ -0x1.a9b66290ea1a3p-1, -0x1.b728345196e3ep-1, -0x1.c38b2f180bdb1p-1,
+ -0x1.ced7af43cc773p-1, -0x1.d906bcf328d46p-1, -0x1.e212104f686e5p-1,
+ -0x1.e9f4156c62ddap-1, -0x1.f0a7efb9230d7p-1, -0x1.f6297cff75cbp-1,
+ -0x1.fa7557f08a517p-1, -0x1.fd88da3d12526p-1, -0x1.ff621e3796d7ep-1,
+ -0x1p+0, -0x1.ff621e3796d7ep-1, -0x1.fd88da3d12526p-1,
+ -0x1.fa7557f08a517p-1, -0x1.f6297cff75cbp-1, -0x1.f0a7efb9230d7p-1,
+ -0x1.e9f4156c62ddap-1, -0x1.e212104f686e5p-1, -0x1.d906bcf328d46p-1,
+ -0x1.ced7af43cc773p-1, -0x1.c38b2f180bdb1p-1, -0x1.b728345196e3ep-1,
+ -0x1.a9b66290ea1a3p-1, -0x1.9b3e047f38741p-1, -0x1.8bc806b151741p-1,
+ -0x1.7b5df226aafafp-1, -0x1.6a09e667f3bcdp-1, -0x1.57d69348cecap-1,
+ -0x1.44cf325091dd6p-1, -0x1.30ff7fce17035p-1, -0x1.1c73b39ae68c8p-1,
+ -0x1.073879922ffeep-1, -0x1.e2b5d3806f63bp-2, -0x1.b5d1009e15ccp-2,
+ -0x1.87de2a6aea963p-2, -0x1.58f9a75ab1fddp-2, -0x1.294062ed59f06p-2,
+ -0x1.f19f97b215f1bp-3, -0x1.8f8b83c69a60bp-3, -0x1.2c8106e8e613ap-3,
+ -0x1.917a6bc29b42cp-4, -0x1.91f65f10dd814p-5
+ };
+
+ uint32_t ix = asuint (x);
+ int32_t e = (ix >> 23) & 0xff;
+ if (__glibc_unlikely (e == 0xff))
+ {
+ if (!(ix << 9))
+ return __math_invalidf (x);
+ return x + x; /* nan */
+ }
+ int32_t m = (ix & ~0u >> 9) | 1 << 23;
+ int32_t s = 143 - e;
+ int32_t p = e - 112;
+ if (__glibc_unlikely (p < 0)) /* |x| < 2^-15 */
+ {
+ uint32_t ax = ix & (~0u>>1);
+ /* Warning: -0x1.3bd3ccp+2f * x underflows for |x| < 0x1.9f03p-129 */
+ if (ax >= 0x19f030u)
+ return fmaf (-0x1.3bd3ccp+2f * x, x, 1.0f);
+ else /* |x| < 0x1.9f03p-129 */
+ return fmaf (-x, x, 1.0f);
+ }
+ if (__glibc_unlikely (p > 31))
+ {
+ if (__glibc_unlikely (p > 63))
+ return 1.0f;
+ int32_t iq = m << (p - 32);
+ return S[(iq + 32) & 127];
+ }
+ int32_t k = m << p;
+ if (__glibc_unlikely (k == 0))
+ {
+ int32_t iq = m >> (32 - p);
+ return S[(iq + 32) & 127];
+ }
+ double z = k;
+ double z2 = z * z;
+ double fs = sn[0] + z2 * (sn[1] + z2 * sn[2]);
+ double fc = cn[0] + z2 * (cn[1] + z2 * cn[2]);
+ uint32_t iq = m >> s;
+ iq = (iq + 1) >> 1;
+ uint32_t is = iq & 127, ic = (iq + 32) & 127;
+ double ts = S[ic], tc = S[is];
+ double r = ts + (ts * z2) * fc - (tc * z) * fs;
+ return r;
+}
+libm_alias_float (__cospi, cospi)
projects / thirdparty / glibc.git / commitdiff
