1 /*
2 * Single-precision SVE acosh(x) function.
3 * Copyright (c) 2023, Arm Limited.
4 * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
5 */
6
7 #include "sv_math.h"
8 #include "pl_sig.h"
9 #include "pl_test.h"
10
11 #define One 0x3f800000
12 #define Thres 0x20000000 /* asuint(0x1p64) - One. */
13
14 #include "sv_log1pf_inline.h"
15
16 static svfloat32_t NOINLINE
special_case(svfloat32_t x,svfloat32_t y,svbool_t special)17 special_case (svfloat32_t x, svfloat32_t y, svbool_t special)
18 {
19 return sv_call_f32 (acoshf, x, y, special);
20 }
21
22 /* Single-precision SVE acosh(x) routine. Implements the same algorithm as
23 vector acoshf and log1p.
24
25 Maximum error is 2.78 ULPs:
26 SV_NAME_F1 (acosh) (0x1.01e996p+0) got 0x1.f45b42p-4
27 want 0x1.f45b3cp-4. */
SV_NAME_F1(acosh)28 svfloat32_t SV_NAME_F1 (acosh) (svfloat32_t x, const svbool_t pg)
29 {
30 svuint32_t ix = svreinterpret_u32 (x);
31 svbool_t special = svcmpge (pg, svsub_x (pg, ix, One), Thres);
32
33 svfloat32_t xm1 = svsub_x (pg, x, 1.0f);
34 svfloat32_t u = svmul_x (pg, xm1, svadd_x (pg, x, 1.0f));
35 svfloat32_t y = sv_log1pf_inline (svadd_x (pg, xm1, svsqrt_x (pg, u)), pg);
36
37 if (unlikely (svptest_any (pg, special)))
38 return special_case (x, y, special);
39 return y;
40 }
41
42 PL_SIG (SV, F, 1, acosh, 1.0, 10.0)
43 PL_TEST_ULP (SV_NAME_F1 (acosh), 2.29)
44 PL_TEST_INTERVAL (SV_NAME_F1 (acosh), 0, 1, 500)
45 PL_TEST_INTERVAL (SV_NAME_F1 (acosh), 1, 0x1p64, 100000)
46 PL_TEST_INTERVAL (SV_NAME_F1 (acosh), 0x1p64, inf, 1000)
47 PL_TEST_INTERVAL (SV_NAME_F1 (acosh), -0, -inf, 1000)
48