diff options
| -rw-r--r-- | lib/msun/src/s_expm1f.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/lib/msun/src/s_expm1f.c b/lib/msun/src/s_expm1f.c index b6ab5b3..6c5d3e7 100644 --- a/lib/msun/src/s_expm1f.c +++ b/lib/msun/src/s_expm1f.c @@ -27,12 +27,13 @@ o_threshold = 8.8721679688e+01,/* 0x42b17180 */ ln2_hi = 6.9313812256e-01,/* 0x3f317180 */ ln2_lo = 9.0580006145e-06,/* 0x3717f7d1 */ invln2 = 1.4426950216e+00,/* 0x3fb8aa3b */ - /* scaled coefficients related to expm1 */ -Q1 = -3.3333335072e-02, /* 0xbd088889 */ -Q2 = 1.5873016091e-03, /* 0x3ad00d01 */ -Q3 = -7.9365076090e-05, /* 0xb8a670cd */ -Q4 = 4.0082177293e-06, /* 0x36867e54 */ -Q5 = -2.0109921195e-07; /* 0xb457edbb */ +/* + * Domain [-0.34568, 0.34568], range ~[-6.694e-10, 6.696e-10]: + * |6 / x * (1 + 2 * (1 / (exp(x) - 1) - 1 / x)) - q(x)| < 2**-30.04 + * Scaled coefficients: Qn_here = 2**n * Qn_for_q (see s_expm1.c): + */ +Q1 = -3.3333212137e-2, /* -0x888868.0p-28 */ +Q2 = 1.5807170421e-3; /* 0xcf3010.0p-33 */ float expm1f(float x) @@ -86,7 +87,7 @@ expm1f(float x) /* x is now in primary range */ hfx = (float)0.5*x; hxs = x*hfx; - r1 = one+hxs*(Q1+hxs*(Q2+hxs*(Q3+hxs*(Q4+hxs*Q5)))); + r1 = one+hxs*(Q1+hxs*Q2); t = (float)3.0-r1*hfx; e = hxs*((r1-t)/((float)6.0 - x*t)); if(k==0) return x - (x*e-hxs); /* c is 0 */ |
