From bfda37935867f9bf271d6074db0accf05c63ad10 Mon Sep 17 00:00:00 2001 From: Szabolcs Nagy Date: Sat, 18 May 2013 14:40:22 +0000 Subject: math: sin cos cleanup * use unsigned arithmetics * use unsigned to store arg reduction quotient (so n&3 is understood) * remove z=0.0 variables, use literal 0 * raise underflow and inexact exceptions properly when x is small * fix spurious underflow in tanl --- src/math/cos.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) (limited to 'src/math/cos.c') diff --git a/src/math/cos.c b/src/math/cos.c index 76990e7f..ee97f68b 100644 --- a/src/math/cos.c +++ b/src/math/cos.c @@ -44,26 +44,28 @@ double cos(double x) { - double y[2],z=0.0; - int32_t n, ix; + double y[2]; + uint32_t ix; + unsigned n; GET_HIGH_WORD(ix, x); + ix &= 0x7fffffff; /* |x| ~< pi/4 */ - ix &= 0x7fffffff; if (ix <= 0x3fe921fb) { - if (ix < 0x3e46a09e) /* if x < 2**-27 * sqrt(2) */ - /* raise inexact if x != 0 */ - if ((int)x == 0) - return 1.0; - return __cos(x, z); + if (ix < 0x3e46a09e) { /* |x| < 2**-27 * sqrt(2) */ + /* raise inexact if x!=0 */ + FORCE_EVAL(x + 0x1p120f); + return 1.0; + } + return __cos(x, 0); } /* cos(Inf or NaN) is NaN */ if (ix >= 0x7ff00000) return x-x; - /* argument reduction needed */ + /* argument reduction */ n = __rem_pio2(x, y); switch (n&3) { case 0: return __cos(y[0], y[1]); -- cgit v1.2.1