diff options
Diffstat (limited to 'src/math/tan.c')
| -rw-r--r-- | src/math/tan.c | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/src/math/tan.c b/src/math/tan.c index 2e1f3c83..9c724a45 100644 --- a/src/math/tan.c +++ b/src/math/tan.c @@ -43,27 +43,28 @@ double tan(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 < 0x3e400000) /* x < 2**-27 */ - /* raise inexact if x != 0 */ - if ((int)x == 0) - return x; - return __tan(x, z, 1); + if (ix < 0x3e400000) { /* |x| < 2**-27 */ + /* raise inexact if x!=0 and underflow if subnormal */ + FORCE_EVAL(ix < 0x00100000 ? x/0x1p120f : x+0x1p120f); + return x; + } + return __tan(x, 0.0, 0); } /* tan(Inf or NaN) is NaN */ if (ix >= 0x7ff00000) return x - x; - /* argument reduction needed */ + /* argument reduction */ n = __rem_pio2(x, y); - return __tan(y[0], y[1], 1 - ((n&1)<<1)); /* n even: 1, n odd: -1 */ + return __tan(y[0], y[1], n&1); } |