34 lines
502 B
C
34 lines
502 B
C
#include "libc/math/libm.h"
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float coshf(float x)
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{
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union {float f; uint32_t i;} u = {.f = x};
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uint32_t w;
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float t;
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/* |x| */
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u.i &= 0x7fffffff;
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x = u.f;
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w = u.i;
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/* |x| < log(2) */
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if (w < 0x3f317217) {
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if (w < 0x3f800000 - (12<<23)) {
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FORCE_EVAL(x + 0x1p120f);
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return 1;
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}
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t = expm1f(x);
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return 1 + t*t/(2*(1+t));
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}
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/* |x| < log(FLT_MAX) */
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if (w < 0x42b17217) {
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t = expf(x);
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return 0.5f*(t + 1/t);
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}
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/* |x| > log(FLT_MAX) or nan */
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t = __expo2f(x);
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return t;
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}
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