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| author | Szabolcs Nagy <nsz@port70.net> | 2013-05-18 14:40:22 +0000 |
|---|---|---|
| committer | Szabolcs Nagy <nsz@port70.net> | 2013-05-18 14:40:22 +0000 |
| commit | bfda37935867f9bf271d6074db0accf05c63ad10 (patch) | |
| tree | 92d7fffcc6fb7fd9caad6f3bde14dcd768d32b66 /src/math/sin.c | |
| parent | 1d5ba3bb5a3f55e10db05219638cfcd967d65417 (diff) | |
| download | musl-bfda37935867f9bf271d6074db0accf05c63ad10.tar.gz | |
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
Diffstat (limited to 'src/math/sin.c')
| -rw-r--r-- | src/math/sin.c | 15 |
1 files changed, 8 insertions, 7 deletions
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 */ |