summaryrefslogtreecommitdiff
path: root/src/math/ilogbl.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/math/ilogbl.c')
-rw-r--r--src/math/ilogbl.c31
1 files changed, 27 insertions, 4 deletions
diff --git a/src/math/ilogbl.c b/src/math/ilogbl.c
index 7df6eb6c..7b1a9cf8 100644
--- a/src/math/ilogbl.c
+++ b/src/math/ilogbl.c
@@ -9,23 +9,46 @@ int ilogbl(long double x)
#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
int ilogbl(long double x)
{
+ #pragma STDC FENV_ACCESS ON
union ldshape u = {x};
uint64_t m = u.i.m;
int e = u.i.se & 0x7fff;
if (!e) {
if (m == 0) {
- FORCE_EVAL(x/x);
+ FORCE_EVAL(0/0.0f);
return FP_ILOGB0;
}
/* subnormal x */
- for (e = -0x3fff+1; m < (uint64_t)1<<63; e--, m<<=1);
+ for (e = -0x3fff+1; m>>63 == 0; e--, m<<=1);
return e;
}
if (e == 0x7fff) {
FORCE_EVAL(0/0.0f);
- /* in ld80 msb is set in inf */
- return m << 1 ? FP_ILOGBNAN : INT_MAX;
+ return m<<1 ? FP_ILOGBNAN : INT_MAX;
+ }
+ return e - 0x3fff;
+}
+#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
+int ilogbl(long double x)
+{
+ #pragma STDC FENV_ACCESS ON
+ union ldshape u = {x};
+ int e = u.i.se & 0x7fff;
+
+ if (!e) {
+ if (x == 0) {
+ FORCE_EVAL(0/0.0f);
+ return FP_ILOGB0;
+ }
+ /* subnormal x */
+ x *= 0x1p120;
+ return ilogbl(x) - 120;
+ }
+ if (e == 0x7fff) {
+ FORCE_EVAL(0/0.0f);
+ u.i.se = 0;
+ return u.f ? FP_ILOGBNAN : INT_MAX;
}
return e - 0x3fff;
}