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/sin.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) (limited to 'src/math/sin.c') diff --git a/src/math/sin.c b/src/math/sin.c index 8e430f85..055e215b 100644 --- a/src/math/sin.c +++ b/src/math/sin.c @@ -44,21 +44,22 @@ double sin(double x) { - double y[2], z=0.0; - int32_t n, ix; + double y[2]; + uint32_t ix; + unsigned n; /* High word of x. */ GET_HIGH_WORD(ix, x); + ix &= 0x7fffffff; /* |x| ~< pi/4 */ - ix &= 0x7fffffff; if (ix <= 0x3fe921fb) { if (ix < 0x3e500000) { /* |x| < 2**-26 */ - /* raise inexact if x != 0 */ - if ((int)x == 0) - return x; + /* raise inexact if x != 0 and underflow if subnormal*/ + FORCE_EVAL(ix < 0x00100000 ? x/0x1p120f : x+0x1p120f); + return x; } - return __sin(x, z, 0); + return __sin(x, 0.0, 0); } /* sin(Inf or NaN) is NaN */ -- cgit v1.2.1