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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/ilogbl.c | |
| parent | af5f6d9556441487e5c66a7a4cfeddf4ed354aa7 (diff) | |
| download | musl-4cec31fc23b28271a2ed0b290e65699dffac3fee.tar.gz musl-4cec31fc23b28271a2ed0b290e65699dffac3fee.tar.bz2 musl-4cec31fc23b28271a2ed0b290e65699dffac3fee.tar.xz musl-4cec31fc23b28271a2ed0b290e65699dffac3fee.zip | |
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/ilogbl.c')
| -rw-r--r-- | src/math/ilogbl.c | 31 |
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; } |