+2015-02-26 Joseph Myers <joseph@codesourcery.com>
+
+ [BZ #18029]
+ * sysdeps/ieee754/ldbl-128ibm/e_ilogbl.c (__ieee754_ilogbl):
+ Adjust exponent of power of 2 down when low part has opposite
+ sign.
+ * math/libm-test.inc (ilogb_test_data): Add more tests.
+
2015-02-26 Alexandre Oliva <aoliva@redhat.com>
[BZ #15969]
4719, 14841, 13064, 14094, 15319, 15467, 15790, 15969, 16560, 16783,
17269, 17523, 17569, 17588, 17792, 17836, 17912, 17916, 17932, 17944,
17949, 17964, 17965, 17967, 17969, 17978, 17987, 17991, 17996, 17998,
- 17999, 18019, 18020.
+ 17999, 18019, 18020, 18029.
* Character encoding and ctype tables were updated to Unicode 7.0.0, using
new generator scripts contributed by Pravin Satpute and Mike FABIAN (Red
TEST_f_i (ilogb, 1024, 10, NO_INEXACT_EXCEPTION),
TEST_f_i (ilogb, -2000, 10, NO_INEXACT_EXCEPTION),
+#if defined TEST_LDOUBLE && LDBL_MANT_DIG >= 57
+ TEST_f_i (ilogb, 0x1.ffffffffffffffp1L, 1, NO_INEXACT_EXCEPTION),
+ TEST_f_i (ilogb, -0x1.ffffffffffffffp1L, 1, NO_INEXACT_EXCEPTION),
+#endif
+
/* ilogb (0.0) == FP_ILOGB0 plus invalid exception */
TEST_f_i (ilogb, 0.0, FP_ILOGB0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
/* ilogb (qNaN) == FP_ILOGBNAN plus invalid exception */
int __ieee754_ilogbl(long double x)
{
- int64_t hx;
+ int64_t hx, hxs;
int ix;
- double xhi;
+ double xhi, xlo;
- xhi = ldbl_high (x);
+ ldbl_unpack (x, &xhi, &xlo);
EXTRACT_WORDS64 (hx, xhi);
+ hxs = hx;
hx &= 0x7fffffffffffffffLL;
if(hx <= 0x0010000000000000LL) {
if(hx==0)
for (ix = -1022, hx<<=11; hx>0; hx<<=1) ix -=1;
return ix;
}
- else if (hx<0x7ff0000000000000LL) return (hx>>52)-0x3ff;
+ else if (hx < 0x7ff0000000000000LL)
+ {
+ int hexp = (hx >> 52) - 0x3ff;
+ /* If the high part is a power of 2, and the low part is
+ nonzero with the opposite sign, the low part affects
+ the exponent. */
+ if ((hx & 0x000fffffffffffffLL) == 0)
+ {
+ int64_t lx;
+ EXTRACT_WORDS64 (lx, xlo);
+ if ((hxs ^ lx) < 0 && (lx & 0x7fffffffffffffffLL) != 0)
+ hexp--;
+ }
+ return hexp;
+ }
else if (FP_ILOGBNAN != INT_MAX) {
/* ISO C99 requires ilogbl(+-Inf) == INT_MAX. */
if (hx==0x7ff0000000000000LL)