1//===-- Implementation header for sinpif16 -------------------------* C++*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_LIBC_SRC___SUPPORT_MATH_SINPIF16_H
10#define LLVM_LIBC_SRC___SUPPORT_MATH_SINPIF16_H
11
12#include "include/llvm-libc-macros/float16-macros.h"
13
14#ifdef LIBC_TYPES_HAS_FLOAT16
15
16#include "sincosf16_utils.h"
17#include "src/__support/FPUtil/FEnvImpl.h"
18#include "src/__support/FPUtil/FPBits.h"
19#include "src/__support/FPUtil/cast.h"
20#include "src/__support/FPUtil/multiply_add.h"
21#include "src/__support/common.h"
22#include "src/__support/macros/config.h"
23#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
24
25namespace LIBC_NAMESPACE_DECL {
26namespace math {
27
28LIBC_INLINE float16 sinpif16(float16 x) {
29 using namespace sincosf16_internal;
30 using FPBits = typename fputil::FPBits<float16>;
31 FPBits xbits(x);
32
33 uint16_t x_u = xbits.uintval();
34 uint16_t x_abs = x_u & 0x7fff;
35 float xf = x;
36
37 // Range reduction:
38 // For |x| > 1/32, we perform range reduction as follows:
39 // Find k and y such that:
40 // x = (k + y) * 1/32
41 // k is an integer
42 // |y| < 0.5
43 //
44 // This is done by performing:
45 // k = round(x * 32)
46 // y = x * 32 - k
47 //
48 // Once k and y are computed, we then deduce the answer by the sine of sum
49 // formula:
50 // sin(x * pi) = sin((k + y) * pi/32)
51 // = sin(k * pi/32) * cos(y * pi/32) +
52 // sin(y * pi/32) * cos(k * pi/32)
53
54 // For signed zeros
55 if (LIBC_UNLIKELY(x_abs == 0U))
56 return x;
57
58 // Numbers greater or equal to 2^10 are integers, or infinity, or NaN
59 if (LIBC_UNLIKELY(x_abs >= 0x6400)) {
60 // Check for NaN or infinity values
61 if (LIBC_UNLIKELY(x_abs >= 0x7c00)) {
62 if (xbits.is_signaling_nan()) {
63 fputil::raise_except_if_required(FE_INVALID);
64 return FPBits::quiet_nan().get_val();
65 }
66 // If value is equal to infinity
67 if (x_abs == 0x7c00) {
68 fputil::set_errno_if_required(EDOM);
69 fputil::raise_except_if_required(FE_INVALID);
70 }
71
72 return x + FPBits::quiet_nan().get_val();
73 }
74 return FPBits::zero(sign: xbits.sign()).get_val();
75 }
76
77 float sin_k = 0, cos_k = 0, sin_y = 0, cosm1_y = 0;
78 sincospif16_eval(xf, sin_k, cos_k, sin_y, cosm1_y);
79
80 if (LIBC_UNLIKELY(sin_y == 0 && sin_k == 0))
81 return FPBits::zero(sign: xbits.sign()).get_val();
82
83 // Since, cosm1_y = cos_y - 1, therefore:
84 // sin(x * pi) = cos_k * sin_y + sin_k + (cosm1_y * sin_k)
85 return fputil::cast<float16>(x: fputil::multiply_add(
86 x: sin_y, y: cos_k, z: fputil::multiply_add(x: cosm1_y, y: sin_k, z: sin_k)));
87}
88
89} // namespace math
90} // namespace LIBC_NAMESPACE_DECL
91
92#endif // LIBC_TYPES_HAS_FLOAT16
93
94#endif // LLVM_LIBC_SRC___SUPPORT_MATH_SINPIF16_H
95