| 1 | /* origin: FreeBSD /usr/src/lib/msun/src/k_cosf.c */ |
| 2 | /* |
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| 3 | * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
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| 4 | * Debugged and optimized by Bruce D. Evans. |
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| 5 | */ |
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| 6 | /* |
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| 7 | * ==================================================== |
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| 8 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 9 | * |
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| 10 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 11 | * Permission to use, copy, modify, and distribute this |
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| 12 | * software is freely granted, provided that this notice |
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| 13 | * is preserved. |
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| 14 | * ==================================================== |
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| 15 | */ |
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| 16 | |
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| 17 | /* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */ |
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| 18 | const C0: f64 = -0.499999997251031003120; /* -0x1ffffffd0c5e81.0p-54 */ |
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| 19 | const C1: f64 = 0.0416666233237390631894; /* 0x155553e1053a42.0p-57 */ |
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| 20 | const C2: f64 = -0.00138867637746099294692; /* -0x16c087e80f1e27.0p-62 */ |
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| 21 | const C3: f64 = 0.0000243904487962774090654; /* 0x199342e0ee5069.0p-68 */ |
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| 22 | |
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| 23 | #[cfg_attr (all(test, assert_no_panic), no_panic::no_panic)] |
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| 24 | pub(crate) fn k_cosf(x: f64) -> f32 { |
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| 25 | let z: f64 = x * x; |
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| 26 | let w: f64 = z * z; |
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| 27 | let r: f64 = C2 + z * C3; |
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| 28 | (((1.0 + z * C0) + w * C1) + (w * z) * r) as f32 |
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| 29 | } |
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| 30 | |
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