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authorSzabolcs Nagy <nsz@port70.net>2013-09-02 23:33:20 +0000
committerSzabolcs Nagy <nsz@port70.net>2013-09-05 11:30:07 +0000
commit4cec31fc23b28271a2ed0b290e65699dffac3fee (patch)
tree82d7775f198079ec26ecc35eba4aa7e7d32b6c36 /src/math
parentaf5f6d9556441487e5c66a7a4cfeddf4ed354aa7 (diff)
downloadmusl-4cec31fc23b28271a2ed0b290e65699dffac3fee.tar.gz
math: ilogb cleanup
* consistent code style * explicit union instead of typedef for double and float bit access * turn FENV_ACCESS ON to make 0/0.0f raise invalid flag * (untested) ld128 version of ilogbl (used by logbl which has ld128 support)
Diffstat (limited to 'src/math')
-rw-r--r--src/math/ilogb.c14
-rw-r--r--src/math/ilogbf.c14
-rw-r--r--src/math/ilogbl.c31
3 files changed, 43 insertions, 16 deletions
diff --git a/src/math/ilogb.c b/src/math/ilogb.c
index 5a1819d8..64d40154 100644
--- a/src/math/ilogb.c
+++ b/src/math/ilogb.c
@@ -3,22 +3,24 @@
int ilogb(double x)
{
- union dshape u = {x};
- int e = u.bits>>52 & 0x7ff;
+ #pragma STDC FENV_ACCESS ON
+ union {double f; uint64_t i;} u = {x};
+ uint64_t i = u.i;
+ int e = i>>52 & 0x7ff;
if (!e) {
- u.bits <<= 12;
- if (u.bits == 0) {
+ i <<= 12;
+ if (i == 0) {
FORCE_EVAL(0/0.0f);
return FP_ILOGB0;
}
/* subnormal x */
- for (e = -0x3ff; u.bits < (uint64_t)1<<63; e--, u.bits<<=1);
+ for (e = -0x3ff; i>>63 == 0; e--, i<<=1);
return e;
}
if (e == 0x7ff) {
FORCE_EVAL(0/0.0f);
- return u.bits<<12 ? FP_ILOGBNAN : INT_MAX;
+ return i<<12 ? FP_ILOGBNAN : INT_MAX;
}
return e - 0x3ff;
}
diff --git a/src/math/ilogbf.c b/src/math/ilogbf.c
index 42cd62e2..e23ba209 100644
--- a/src/math/ilogbf.c
+++ b/src/math/ilogbf.c
@@ -3,22 +3,24 @@
int ilogbf(float x)
{
- union fshape u = {x};
- int e = u.bits>>23 & 0xff;
+ #pragma STDC FENV_ACCESS ON
+ union {float f; uint32_t i;} u = {x};
+ uint32_t i = u.i;
+ int e = i>>23 & 0xff;
if (!e) {
- u.bits <<= 9;
- if (u.bits == 0) {
+ i <<= 9;
+ if (i == 0) {
FORCE_EVAL(0/0.0f);
return FP_ILOGB0;
}
/* subnormal x */
- for (e = -0x7f; u.bits < (uint32_t)1<<31; e--, u.bits<<=1);
+ for (e = -0x7f; i>>31 == 0; e--, i<<=1);
return e;
}
if (e == 0xff) {
FORCE_EVAL(0/0.0f);
- return u.bits<<9 ? FP_ILOGBNAN : INT_MAX;
+ return i<<9 ? FP_ILOGBNAN : INT_MAX;
}
return e - 0x7f;
}
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;
}