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/sinl.c | 29 ++++++++++++++--------------- 1 file changed, 14 insertions(+), 15 deletions(-) (limited to 'src/math/sinl.c') diff --git a/src/math/sinl.c b/src/math/sinl.c index 7e0b44f4..6ca99986 100644 --- a/src/math/sinl.c +++ b/src/math/sinl.c @@ -37,33 +37,32 @@ long double sinl(long double x) long double sinl(long double x) { union IEEEl2bits z; - int e0, s; + unsigned n; long double y[2]; long double hi, lo; z.e = x; - s = z.bits.sign; z.bits.sign = 0; - /* If x = +-0 or x is a subnormal number, then sin(x) = x */ - if (z.bits.exp == 0) - return x; - /* If x = NaN or Inf, then sin(x) = NaN. */ - if (z.bits.exp == 32767) + if (z.bits.exp == 0x7fff) return (x - x) / (x - x); - /* Optimize the case where x is already within range. */ + /* |x| < (double)pi/4 */ if (z.e < M_PI_4) { - hi = __sinl(z.e, 0, 0); - return s ? -hi : hi; + /* |x| < 0x1p-64 */ + if (z.bits.exp < 0x3fff - 64) { + /* raise inexact if x!=0 and underflow if subnormal */ + FORCE_EVAL(z.bits.exp == 0 ? x/0x1p120f : x+0x1p120f); + return x; + } + return __sinl(x, 0.0, 0); } - e0 = __rem_pio2l(x, y); + n = __rem_pio2l(x, y); hi = y[0]; lo = y[1]; - - switch (e0 & 3) { + switch (n & 3) { case 0: hi = __sinl(hi, lo, 1); break; @@ -71,10 +70,10 @@ long double sinl(long double x) hi = __cosl(hi, lo); break; case 2: - hi = - __sinl(hi, lo, 1); + hi = -__sinl(hi, lo, 1); break; case 3: - hi = - __cosl(hi, lo); + hi = -__cosl(hi, lo); break; } return hi; -- cgit v1.2.1