77 lines
1.9 KiB
C
77 lines
1.9 KiB
C
/* origin: FreeBSD /usr/src/lib/msun/src/s_sinf.c */
|
|
/*
|
|
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
|
|
* Optimized by Bruce D. Evans.
|
|
*/
|
|
/*
|
|
* ====================================================
|
|
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
|
*
|
|
* Developed at SunPro, a Sun Microsystems, Inc. business.
|
|
* Permission to use, copy, modify, and distribute this
|
|
* software is freely granted, provided that this notice
|
|
* is preserved.
|
|
* ====================================================
|
|
*/
|
|
|
|
#include "libc/math/libm.h"
|
|
|
|
/* Small multiples of pi/2 rounded to double precision. */
|
|
static const double
|
|
s1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
|
|
s2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
|
|
s3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
|
|
s4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
|
|
|
|
float sinf(float x)
|
|
{
|
|
double y;
|
|
uint32_t ix;
|
|
int n, sign;
|
|
|
|
GET_FLOAT_WORD(ix, x);
|
|
sign = ix >> 31;
|
|
ix &= 0x7fffffff;
|
|
|
|
if (ix <= 0x3f490fda) { /* |x| ~<= pi/4 */
|
|
if (ix < 0x39800000) { /* |x| < 2**-12 */
|
|
/* raise inexact if x!=0 and underflow if subnormal */
|
|
FORCE_EVAL(ix < 0x00800000 ? x/0x1p120f : x+0x1p120f);
|
|
return x;
|
|
}
|
|
return __sindf(x);
|
|
}
|
|
if (ix <= 0x407b53d1) { /* |x| ~<= 5*pi/4 */
|
|
if (ix <= 0x4016cbe3) { /* |x| ~<= 3pi/4 */
|
|
if (sign)
|
|
return -__cosdf(x + s1pio2);
|
|
else
|
|
return __cosdf(x - s1pio2);
|
|
}
|
|
return __sindf(sign ? -(x + s2pio2) : -(x - s2pio2));
|
|
}
|
|
if (ix <= 0x40e231d5) { /* |x| ~<= 9*pi/4 */
|
|
if (ix <= 0x40afeddf) { /* |x| ~<= 7*pi/4 */
|
|
if (sign)
|
|
return __cosdf(x + s3pio2);
|
|
else
|
|
return -__cosdf(x - s3pio2);
|
|
}
|
|
return __sindf(sign ? x + s4pio2 : x - s4pio2);
|
|
}
|
|
|
|
/* sin(Inf or NaN) is NaN */
|
|
if (ix >= 0x7f800000)
|
|
return x - x;
|
|
|
|
/* general argument reduction needed */
|
|
n = __rem_pio2f(x, &y);
|
|
switch (n&3) {
|
|
case 0: return __sindf(y);
|
|
case 1: return __cosdf(y);
|
|
case 2: return __sindf(-y);
|
|
default:
|
|
return -__cosdf(y);
|
|
}
|
|
}
|