1 /*
2 * Double-precision SVE sinpi(x) function.
3 *
4 * Copyright (c) 2023, Arm Limited.
5 * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
6 */
7
8 #include "mathlib.h"
9 #include "sv_math.h"
10 #include "pl_sig.h"
11 #include "pl_test.h"
12 #include "poly_sve_f64.h"
13
14 static const struct data
15 {
16 double poly[10];
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 };
25
26 /* A fast SVE implementation of sinpi.
27 Maximum error 3.10 ULP:
28 _ZGVsMxv_sinpi(0x1.df1a14f1b235p-2) got 0x1.fd64f541606cp-1
29 want 0x1.fd64f541606c3p-1. */
SV_NAME_D1(sinpi)30 svfloat64_t SV_NAME_D1 (sinpi) (svfloat64_t x, const svbool_t pg)
31 {
32 const struct data *d = ptr_barrier (&data);
33
34 /* range reduction into -1/2 .. 1/2)
35 with n = rint(x) and r = r - n. */
36 svfloat64_t n = svrinta_x (pg, x);
37 svfloat64_t r = svsub_x (pg, x, n);
38
39 /* Result should be negated based on if n is odd or not. */
40 svuint64_t intn = svreinterpret_u64 (svcvt_s64_x (pg, n));
41 svuint64_t sign = svlsl_z (pg, intn, 63);
42
43 /* y = sin(r). */
44 svfloat64_t r2 = svmul_x (pg, r, r);
45 svfloat64_t r4 = svmul_x (pg, r2, r2);
46 svfloat64_t y = sv_pw_horner_9_f64_x (pg, r2, r4, d->poly);
47 y = svmul_x (pg, y, r);
48
49 return svreinterpret_f64 (sveor_x (pg, svreinterpret_u64 (y), sign));
50 }
51
52 PL_SIG (SV, D, 1, sinpi, -0.9, 0.9)
53 PL_TEST_ULP (SV_NAME_D1 (sinpi), 2.61)
54 PL_TEST_SYM_INTERVAL (SV_NAME_D1 (sinpi), 0, 0x1p-63, 5000)
55 PL_TEST_SYM_INTERVAL (SV_NAME_D1 (sinpi), 0x1p-63, 0.5, 10000)
56 PL_TEST_SYM_INTERVAL (SV_NAME_D1 (sinpi), 0.5, 0x1p51, 10000)
57 PL_TEST_SYM_INTERVAL (SV_NAME_D1 (sinpi), 0x1p51, inf, 10000)
58