diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/e_logl.c')
| -rw-r--r-- | sysdeps/ieee754/ldbl-128ibm/e_logl.c | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/e_logl.c b/sysdeps/ieee754/ldbl-128ibm/e_logl.c index 15b5edfab3..b7db2b9784 100644 --- a/sysdeps/ieee754/ldbl-128ibm/e_logl.c +++ b/sysdeps/ieee754/ldbl-128ibm/e_logl.c @@ -188,18 +188,20 @@ static const long double long double __ieee754_logl(long double x) { - long double z, y, w; - ieee854_long_double_shape_type u, t; + long double z, y, w, t; unsigned int m; int k, e; + double xhi; + uint32_t hx, lx; - u.value = x; - m = u.parts32.w0; + xhi = ldbl_high (x); + EXTRACT_WORDS (hx, lx, xhi); + m = hx; /* Check for IEEE special cases. */ k = m & 0x7fffffff; /* log(0) = -infinity. */ - if ((k | u.parts32.w1 | (u.parts32.w2 & 0x7fffffff) | u.parts32.w3) == 0) + if ((k | lx) == 0) { return -0.5L / ZERO; } @@ -219,7 +221,7 @@ __ieee754_logl(long double x) { z = x - 1.0L; k = 64; - t.value = 1.0L; + t = 1.0L; e = 0; } else @@ -236,10 +238,8 @@ __ieee754_logl(long double x) k = (m - 0xff000) >> 13; /* t is the argument 0.5 + (k+26)/128 of the nearest item to u in the lookup table. */ - t.parts32.w0 = 0x3ff00000 + (k << 13); - t.parts32.w1 = 0; - t.parts32.w2 = 0; - t.parts32.w3 = 0; + INSERT_WORDS (xhi, 0x3ff00000 + (k << 13), 0); + t = xhi; w0 += 0x100000; e -= 1; k += 64; @@ -247,17 +247,15 @@ __ieee754_logl(long double x) else { k = (m - 0xfe000) >> 14; - t.parts32.w0 = 0x3fe00000 + (k << 14); - t.parts32.w1 = 0; - t.parts32.w2 = 0; - t.parts32.w3 = 0; + INSERT_WORDS (xhi, 0x3fe00000 + (k << 14), 0); + t = xhi; } - u.value = __scalbnl (u.value, ((int) ((w0 - u.parts32.w0) * 2)) >> 21); + x = __scalbnl (x, ((int) ((w0 - hx) * 2)) >> 21); /* log(u) = log( t u/t ) = log(t) + log(u/t) log(t) is tabulated in the lookup table. Express log(u/t) = log(1+z), where z = u/t - 1 = (u-t)/t. cf. Cody & Waite. */ - z = (u.value - t.value) / t.value; + z = (x - t) / t; } /* Series expansion of log(1+z). */ w = z * z; @@ -284,7 +282,7 @@ __ieee754_logl(long double x) y += e * ln2b; /* Base 2 exponent offset times ln(2). */ y += z; y += logtbl[k-26]; /* log(t) - (t-1) */ - y += (t.value - 1.0L); + y += (t - 1.0L); y += e * ln2a; return y; } |