1 /*
2 * Double-precision SVE sinpi(x) function.
3 *
4 * Copyright (c) 2023-2024, Arm Limited.
5 * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
6 */
7
8 #include "sv_math.h"
9 #include "mathlib.h"
10 #include "test_sig.h"
11 #include "test_defs.h"
12 #include "sv_poly_f64.h"
13
14 static const struct data
15 {
16 double poly[10], range_val;
17 } data = {
18 /* Polynomial coefficients generated using Remez algorithm,
19 see sinpi.sollya for details. */
20 .poly = { 0x1.921fb54442d184p1, -0x1.4abbce625be53p2, 0x1.466bc6775ab16p1,
21 -0x1.32d2cce62dc33p-1, 0x1.507834891188ep-4, -0x1.e30750a28c88ep-8,
22 0x1.e8f48308acda4p-12, -0x1.6fc0032b3c29fp-16,
23 0x1.af86ae521260bp-21, -0x1.012a9870eeb7dp-25 },
24 .range_val = 0x1p63,
25 };
26
27 /* A fast SVE implementation of sinpi.
28 Maximum error 3.10 ULP:
29 _ZGVsMxv_sinpi(0x1.df1a14f1b235p-2) got 0x1.fd64f541606cp-1
30 want 0x1.fd64f541606c3p-1. */
SV_NAME_D1(sinpi)31 svfloat64_t SV_NAME_D1 (sinpi) (svfloat64_t x, const svbool_t pg)
32 {
33 const struct data *d = ptr_barrier (&data);
34
35 /* range reduction into -1/2 .. 1/2)
36 with n = rint(x) and r = r - n. */
37 svfloat64_t n = svrinta_x (pg, x);
38 svfloat64_t r = svsub_x (pg, x, n);
39
40 /* Result should be negated based on if n is odd or not. */
41 svbool_t cmp = svaclt (pg, x, d->range_val);
42 svuint64_t intn = svreinterpret_u64 (svcvt_s64_z (pg, n));
43 svuint64_t sign = svlsl_z (cmp, intn, 63);
44
45 /* y = sin(r). */
46 svfloat64_t r2 = svmul_x (pg, r, r);
47 svfloat64_t r4 = svmul_x (pg, r2, r2);
48 svfloat64_t y = sv_pw_horner_9_f64_x (pg, r2, r4, d->poly);
49 y = svmul_x (pg, y, r);
50
51 return svreinterpret_f64 (sveor_x (pg, svreinterpret_u64 (y), sign));
52 }
53
54 #if WANT_TRIGPI_TESTS
55 TEST_ULP (SV_NAME_D1 (sinpi), 2.61)
56 TEST_DISABLE_FENV (SV_NAME_D1 (sinpi))
57 TEST_SYM_INTERVAL (SV_NAME_D1 (sinpi), 0, 0x1p-63, 5000)
58 TEST_SYM_INTERVAL (SV_NAME_D1 (sinpi), 0x1p-63, 0.5, 10000)
59 TEST_SYM_INTERVAL (SV_NAME_D1 (sinpi), 0.5, 0x1p51, 10000)
60 TEST_SYM_INTERVAL (SV_NAME_D1 (sinpi), 0x1p51, inf, 10000)
61 #endif
62 CLOSE_SVE_ATTR
63