1*412f47f9SXin Li /*
2*412f47f9SXin Li * Single-precision SVE sinpi(x) function.
3*412f47f9SXin Li *
4*412f47f9SXin Li * Copyright (c) 2023, Arm Limited.
5*412f47f9SXin Li * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
6*412f47f9SXin Li */
7*412f47f9SXin Li
8*412f47f9SXin Li #include "mathlib.h"
9*412f47f9SXin Li #include "sv_math.h"
10*412f47f9SXin Li #include "pl_sig.h"
11*412f47f9SXin Li #include "pl_test.h"
12*412f47f9SXin Li #include "poly_sve_f32.h"
13*412f47f9SXin Li
14*412f47f9SXin Li static const struct data
15*412f47f9SXin Li {
16*412f47f9SXin Li float poly[6];
17*412f47f9SXin Li } data = {
18*412f47f9SXin Li /* Taylor series coefficents for sin(pi * x). */
19*412f47f9SXin Li .poly = { 0x1.921fb6p1f, -0x1.4abbcep2f, 0x1.466bc6p1f, -0x1.32d2ccp-1f,
20*412f47f9SXin Li 0x1.50783p-4f, -0x1.e30750p-8f },
21*412f47f9SXin Li };
22*412f47f9SXin Li
23*412f47f9SXin Li /* A fast SVE implementation of sinpif.
24*412f47f9SXin Li Maximum error 2.48 ULP:
25*412f47f9SXin Li _ZGVsMxv_sinpif(0x1.d062b6p-2) got 0x1.fa8c06p-1
26*412f47f9SXin Li want 0x1.fa8c02p-1. */
SV_NAME_F1(sinpi)27*412f47f9SXin Li svfloat32_t SV_NAME_F1 (sinpi) (svfloat32_t x, const svbool_t pg)
28*412f47f9SXin Li {
29*412f47f9SXin Li const struct data *d = ptr_barrier (&data);
30*412f47f9SXin Li
31*412f47f9SXin Li /* range reduction into -1/2 .. 1/2
32*412f47f9SXin Li with n = rint(x) and r = r - n. */
33*412f47f9SXin Li svfloat32_t n = svrinta_x (pg, x);
34*412f47f9SXin Li svfloat32_t r = svsub_x (pg, x, n);
35*412f47f9SXin Li
36*412f47f9SXin Li /* Result should be negated based on if n is odd or not. */
37*412f47f9SXin Li svuint32_t intn = svreinterpret_u32 (svcvt_s32_x (pg, n));
38*412f47f9SXin Li svuint32_t sign = svlsl_z (pg, intn, 31);
39*412f47f9SXin Li
40*412f47f9SXin Li /* y = sin(r). */
41*412f47f9SXin Li svfloat32_t r2 = svmul_x (pg, r, r);
42*412f47f9SXin Li svfloat32_t y = sv_horner_5_f32_x (pg, r2, d->poly);
43*412f47f9SXin Li y = svmul_x (pg, y, r);
44*412f47f9SXin Li
45*412f47f9SXin Li return svreinterpret_f32 (sveor_x (pg, svreinterpret_u32 (y), sign));
46*412f47f9SXin Li }
47*412f47f9SXin Li
48*412f47f9SXin Li PL_SIG (SV, F, 1, sinpi, -0.9, 0.9)
49*412f47f9SXin Li PL_TEST_ULP (SV_NAME_F1 (sinpi), 1.99)
50*412f47f9SXin Li PL_TEST_SYM_INTERVAL (SV_NAME_F1 (sinpi), 0, 0x1p-31, 5000)
51*412f47f9SXin Li PL_TEST_SYM_INTERVAL (SV_NAME_F1 (sinpi), 0x1p-31, 0.5, 10000)
52*412f47f9SXin Li PL_TEST_SYM_INTERVAL (SV_NAME_F1 (sinpi), 0.5, 0x1p22f, 10000)
53*412f47f9SXin Li PL_TEST_SYM_INTERVAL (SV_NAME_F1 (sinpi), 0x1p22f, inf, 10000)
54