1 /* origin: FreeBSD /usr/src/lib/msun/src/s_cosf.c */
3 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
4 * Optimized by Bruce D. Evans.
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
10 * Developed at SunPro, a Sun Microsystems, Inc. business.
11 * Permission to use, copy, modify, and distribute this
12 * software is freely granted, provided that this notice
14 * ====================================================
17 use super::{k_cosf, k_sinf, rem_pio2f}
;
19 use core
::f64::consts
::FRAC_PI_2
;
21 /* Small multiples of pi/2 rounded to double precision. */
22 const C1_PIO2
: f64 = 1. * FRAC_PI_2
; /* 0x3FF921FB, 0x54442D18 */
23 const C2_PIO2
: f64 = 2. * FRAC_PI_2
; /* 0x400921FB, 0x54442D18 */
24 const C3_PIO2
: f64 = 3. * FRAC_PI_2
; /* 0x4012D97C, 0x7F3321D2 */
25 const C4_PIO2
: f64 = 4. * FRAC_PI_2
; /* 0x401921FB, 0x54442D18 */
27 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
28 pub fn cosf(x
: f32) -> f32 {
31 let x1p120
= f32::from_bits(0x7b800000); // 0x1p120f === 2 ^ 120
33 let mut ix
= x
.to_bits();
34 let sign
= (ix
>> 31) != 0;
41 /* raise inexact if x != 0 */
42 force_eval
!(x
+ x1p120
);
51 return -k_cosf(if sign { x64 + C2_PIO2 }
else { x64 - C2_PIO2 }
);
53 return k_sinf(x64
+ C1_PIO2
);
55 return k_sinf(C1_PIO2
- x64
);
62 return k_cosf(if sign { x64 + C4_PIO2 }
else { x64 - C4_PIO2 }
);
64 return k_sinf(-x64
- C3_PIO2
);
66 return k_sinf(x64
- C3_PIO2
);
70 /* cos(Inf or NaN) is NaN */
75 /* general argument reduction needed */
76 let (n
, y
) = rem_pio2f(x
);