diff options
Diffstat (limited to 'src/math/tanf.c')
| -rw-r--r-- | src/math/tanf.c | 32 |
1 files changed, 17 insertions, 15 deletions
diff --git a/src/math/tanf.c b/src/math/tanf.c index 8b0dfb20..aba19777 100644 --- a/src/math/tanf.c +++ b/src/math/tanf.c @@ -26,37 +26,39 @@ t4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */ float tanf(float x) { double y; - int32_t n, hx, ix; + uint32_t ix; + unsigned n, sign; - GET_FLOAT_WORD(hx, x); - ix = hx & 0x7fffffff; + GET_FLOAT_WORD(ix, x); + sign = ix >> 31; + ix &= 0x7fffffff; if (ix <= 0x3f490fda) { /* |x| ~<= pi/4 */ - if (ix < 0x39800000) /* |x| < 2**-12 */ - /* return x and raise inexact if x != 0 */ - if ((int)x == 0) - return x; - return __tandf(x, 1); + if (ix < 0x39800000) { /* |x| < 2**-12 */ + /* raise inexact if x!=0 and underflow if subnormal */ + FORCE_EVAL(ix < 0x00800000 ? x/0x1p120f : x+0x1p120f); + return x; + } + return __tandf(x, 0); } if (ix <= 0x407b53d1) { /* |x| ~<= 5*pi/4 */ if (ix <= 0x4016cbe3) /* |x| ~<= 3pi/4 */ - return __tandf((hx > 0 ? x-t1pio2 : x+t1pio2), -1); + return __tandf((sign ? x+t1pio2 : x-t1pio2), 1); else - return __tandf((hx > 0 ? x-t2pio2 : x+t2pio2), 1); + return __tandf((sign ? x+t2pio2 : x-t2pio2), 0); } if (ix <= 0x40e231d5) { /* |x| ~<= 9*pi/4 */ if (ix <= 0x40afeddf) /* |x| ~<= 7*pi/4 */ - return __tandf((hx > 0 ? x-t3pio2 : x+t3pio2), -1); + return __tandf((sign ? x+t3pio2 : x-t3pio2), 1); else - return __tandf((hx > 0 ? x-t4pio2 : x+t4pio2), 1); + return __tandf((sign ? x+t4pio2 : x-t4pio2), 0); } /* tan(Inf or NaN) is NaN */ if (ix >= 0x7f800000) return x - x; - /* general argument reduction needed */ + /* argument reduction */ n = __rem_pio2f(x, &y); - /* integer parameter: n even: 1; n odd: -1 */ - return __tandf(y, 1-((n&1)<<1)); + return __tandf(y, n&1); } |