1*412f47f9SXin Li /*
2*412f47f9SXin Li * Single-precision SVE cosh(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 "sv_math.h"
9*412f47f9SXin Li #include "pl_sig.h"
10*412f47f9SXin Li #include "pl_test.h"
11*412f47f9SXin Li
12*412f47f9SXin Li #include "sv_expf_inline.h"
13*412f47f9SXin Li
14*412f47f9SXin Li static const struct data
15*412f47f9SXin Li {
16*412f47f9SXin Li struct sv_expf_data expf_consts;
17*412f47f9SXin Li uint32_t special_bound;
18*412f47f9SXin Li } data = {
19*412f47f9SXin Li .expf_consts = SV_EXPF_DATA,
20*412f47f9SXin Li /* 0x1.5a92d8p+6: expf overflows above this, so have to use special case. */
21*412f47f9SXin Li .special_bound = 0x42ad496c,
22*412f47f9SXin Li };
23*412f47f9SXin Li
24*412f47f9SXin Li static svfloat32_t NOINLINE
special_case(svfloat32_t x,svfloat32_t y,svbool_t pg)25*412f47f9SXin Li special_case (svfloat32_t x, svfloat32_t y, svbool_t pg)
26*412f47f9SXin Li {
27*412f47f9SXin Li return sv_call_f32 (coshf, x, y, pg);
28*412f47f9SXin Li }
29*412f47f9SXin Li
30*412f47f9SXin Li /* Single-precision vector cosh, using vector expf.
31*412f47f9SXin Li Maximum error is 1.89 ULP:
32*412f47f9SXin Li _ZGVsMxv_coshf (-0x1.65898cp+6) got 0x1.f00aep+127
33*412f47f9SXin Li want 0x1.f00adcp+127. */
SV_NAME_F1(cosh)34*412f47f9SXin Li svfloat32_t SV_NAME_F1 (cosh) (svfloat32_t x, svbool_t pg)
35*412f47f9SXin Li {
36*412f47f9SXin Li const struct data *d = ptr_barrier (&data);
37*412f47f9SXin Li
38*412f47f9SXin Li svfloat32_t ax = svabs_x (pg, x);
39*412f47f9SXin Li svbool_t special = svcmpge (pg, svreinterpret_u32 (ax), d->special_bound);
40*412f47f9SXin Li
41*412f47f9SXin Li /* Calculate cosh by exp(x) / 2 + exp(-x) / 2. */
42*412f47f9SXin Li svfloat32_t t = expf_inline (ax, pg, &d->expf_consts);
43*412f47f9SXin Li svfloat32_t half_t = svmul_x (pg, t, 0.5);
44*412f47f9SXin Li svfloat32_t half_over_t = svdivr_x (pg, t, 0.5);
45*412f47f9SXin Li
46*412f47f9SXin Li if (unlikely (svptest_any (pg, special)))
47*412f47f9SXin Li return special_case (x, svadd_x (pg, half_t, half_over_t), special);
48*412f47f9SXin Li
49*412f47f9SXin Li return svadd_x (pg, half_t, half_over_t);
50*412f47f9SXin Li }
51*412f47f9SXin Li
52*412f47f9SXin Li PL_SIG (SV, F, 1, cosh, -10.0, 10.0)
53*412f47f9SXin Li PL_TEST_ULP (SV_NAME_F1 (cosh), 1.39)
54*412f47f9SXin Li PL_TEST_SYM_INTERVAL (SV_NAME_F1 (cosh), 0, 0x1p-63, 100)
55*412f47f9SXin Li PL_TEST_SYM_INTERVAL (SV_NAME_F1 (cosh), 0, 0x1.5a92d8p+6, 80000)
56*412f47f9SXin Li PL_TEST_SYM_INTERVAL (SV_NAME_F1 (cosh), 0x1.5a92d8p+6, inf, 2000)
57