diff options
Diffstat (limited to 'lib/msun/src/s_cosf.c')
-rw-r--r-- | lib/msun/src/s_cosf.c | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/lib/msun/src/s_cosf.c b/lib/msun/src/s_cosf.c index 3a854b0..ec7f0cf 100644 --- a/lib/msun/src/s_cosf.c +++ b/lib/msun/src/s_cosf.c @@ -20,25 +20,56 @@ static char rcsid[] = "$FreeBSD$"; #include "math.h" #include "math_private.h" +/* Small multiples of pi/2 rounded to double precision. */ +static const double +c1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */ +c2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */ +c3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */ +c4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */ + +static inline float +__kernel_cosdf(double x) +{ + return __kernel_cosf((float)x, x - (float)x); +} + +static inline float +__kernel_sindf(double x) +{ + return __kernel_sinf((float)x, x - (float)x, 1); +} + float cosf(float x) { float y[2]; int32_t n,ix; + x = fabsf(x); GET_FLOAT_WORD(ix,x); - ix &= 0x7fffffff; if(ix <= 0x3f490fda) { /* |x| ~<= pi/4 */ if(ix<0x39800000) /* |x| < 2**-12 */ if(((int)x)==0) return 1.0; /* 1 with inexact if x != 0 */ return __kernel_cosf(x,0.0); } + if(ix<=0x407b53d1) { /* |x| <= ~5*pi/4 */ + if(ix<=0x4016cbe3) /* |x| <= ~3pi/4 */ + return -__kernel_sindf(x - c1pio2); + else + return -__kernel_cosdf(x - c2pio2); + } + if(ix<=0x40e231d5) { /* |x| <= ~9*pi/4 */ + if(ix<=0x40afeddf) /* |x| <= ~7*pi/4 */ + return __kernel_sindf(x - c3pio2); + else + return __kernel_cosdf(x - c4pio2); + } /* cos(Inf or NaN) is NaN */ else if (ix>=0x7f800000) return x-x; - /* argument reduction needed */ + /* general argument reduction needed */ else { n = __ieee754_rem_pio2f(x,y); switch(n&3) { |