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