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| author | Szabolcs Nagy <nsz@port70.net> | 2013-09-02 23:33:20 +0000 |
|---|---|---|
| committer | Szabolcs Nagy <nsz@port70.net> | 2013-09-05 11:30:07 +0000 |
| commit | 4cec31fc23b28271a2ed0b290e65699dffac3fee (patch) | |
| tree | 82d7775f198079ec26ecc35eba4aa7e7d32b6c36 /src/math/ilogb.c | |
| parent | af5f6d9556441487e5c66a7a4cfeddf4ed354aa7 (diff) | |
| download | musl-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/ilogb.c')
| -rw-r--r-- | src/math/ilogb.c | 14 |
1 files changed, 8 insertions, 6 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; } |