pxfm/sin_cosf/
argument_reduction_pi.rs

1/*
2 * // Copyright (c) Radzivon Bartoshyk 8/2025. All rights reserved.
3 * //
4 * // Redistribution and use in source and binary forms, with or without modification,
5 * // are permitted provided that the following conditions are met:
6 * //
7 * // 1.  Redistributions of source code must retain the above copyright notice, this
8 * // list of conditions and the following disclaimer.
9 * //
10 * // 2.  Redistributions in binary form must reproduce the above copyright notice,
11 * // this list of conditions and the following disclaimer in the documentation
12 * // and/or other materials provided with the distribution.
13 * //
14 * // 3.  Neither the name of the copyright holder nor the names of its
15 * // contributors may be used to endorse or promote products derived from
16 * // this software without specific prior written permission.
17 * //
18 * // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19 * // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21 * // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
22 * // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
24 * // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
25 * // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
26 * // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29use crate::common::f_fmla;
30use crate::rounding::CpuRound;
31
32#[derive(Debug, Copy, Clone)]
33pub(crate) struct ArgumentReducerPi {
34    pub(crate) x: f64,
35}
36
37impl ArgumentReducerPi {
38    // Return k and y, where
39    // k = round(x * 32 / pi) and y = (x * 32 / pi) - k.
40    #[inline(always)]
41    pub(crate) fn reduce(self) -> (f64, i64) {
42        let kd = (self.x * 32.).cpu_round();
43        let y = f_fmla(self.x, 32.0, -kd);
44        (y, unsafe {
45            kd.to_int_unchecked::<i64>() // indeterminate values is always filtered out before this call, as well only lowest bits are used
46        })
47    }
48
49    // Return k and y, where
50    // k = round(x * 32 / pi) and y = (x * 32 / pi) - k.
51    #[inline(always)]
52    #[allow(unused)]
53    pub(crate) fn reduce_fma(self) -> (f64, i64) {
54        let kd = (self.x * 32.).round();
55        let y = f64::mul_add(self.x, 32.0, -kd);
56        (y, unsafe {
57            kd.to_int_unchecked::<i64>() // indeterminate values is always filtered out before this call, as well only lowest bits are used
58        })
59    }
60
61    // Return k and y, where
62    // k = round(x * 2 / pi) and y = (x * 2 / pi) - k.
63    #[inline(always)]
64    pub(crate) fn reduce_0p25(self) -> (f64, i64) {
65        let kd = (self.x + self.x).cpu_round();
66        let y = f_fmla(kd, -0.5, self.x);
67        (y, unsafe {
68            kd.to_int_unchecked::<i64>() // indeterminate values is always filtered out before this call, as well only lowest bits are used
69        })
70    }
71
72    // Return k and y, where
73    // k = round(x * 2 / pi) and y = (x * 2 / pi) - k.
74    #[inline(always)]
75    #[allow(unused)]
76    pub(crate) fn reduce_0p25_fma(self) -> (f64, i64) {
77        let kd = (self.x + self.x).round();
78        let y = f64::mul_add(kd, -0.5, self.x);
79        (y, unsafe {
80            kd.to_int_unchecked::<i64>() // indeterminate values is always filtered out before this call, as well only lowest bits are used
81        })
82    }
83
84    //
85    // // Return k and y, where
86    // // k = round(x * 2 / pi) and y = (x * 2 / pi) - k.
87    // #[inline]
88    // pub(crate) fn reduce_0p10(self) -> (f64, i64) {
89    //     let kd = (self.x * 4.).round();
90    //     let y = f_fmla(kd, -0.25, self.x);
91    //     (y, kd as i64)
92    // }
93}
pxfm/sin_cosf/argument_reduction_pi.rs

pxfm/sin_cosf/
argument_reduction_pi.rs
