diff options
| author | ppatience0 <ppatience0@gmail.com> | 2013-05-06 19:37:51 -0400 |
|---|---|---|
| committer | ppatience0 <ppatience0@gmail.com> | 2013-05-06 19:37:51 -0400 |
| commit | a1bc7c76ba7392960086e53132bbc5f358bd6b03 (patch) | |
| tree | 64a3822652f2ff9eed722990175b7c036628242c /sys/src/ape/lib/ap/plan9/frexp.c | |
| parent | 5ac6088b96c67e9799bc8009d46b72819521da87 (diff) | |
| parent | cd66b11f67654edfa54cab05422310d5c923784a (diff) | |
merge
Diffstat (limited to 'sys/src/ape/lib/ap/plan9/frexp.c')
| -rw-r--r-- | sys/src/ape/lib/ap/plan9/frexp.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/sys/src/ape/lib/ap/plan9/frexp.c b/sys/src/ape/lib/ap/plan9/frexp.c index 588f90cee..0d81f52c7 100644 --- a/sys/src/ape/lib/ap/plan9/frexp.c +++ b/sys/src/ape/lib/ap/plan9/frexp.c @@ -6,6 +6,7 @@ #define MASK 0x7ffL #define SHIFT 20 #define BIAS 1022L +#define SIG 52 typedef union { @@ -25,13 +26,18 @@ typedef union double frexp(double d, int *ep) { - Cheat x; + Cheat x, a; - if(d == 0) { - *ep = 0; - return 0; - } + *ep = 0; + /* order matters: only isNaN can operate on NaN */ + if(isNaN(d) || isInf(d, 0) || d == 0) + return d; x.d = d; + a.d = fabs(d); + if((a.ms >> SHIFT) == 0){ /* normalize subnormal numbers */ + x.d = (double)(1ULL<<SIG) * d; + *ep = -SIG; + } *ep = ((x.ms >> SHIFT) & MASK) - BIAS; x.ms &= ~(MASK << SHIFT); x.ms |= BIAS << SHIFT; |