diff options
Diffstat (limited to 'src/pkg/runtime/float.c')
-rw-r--r-- | src/pkg/runtime/float.c | 171 |
1 files changed, 4 insertions, 167 deletions
diff --git a/src/pkg/runtime/float.c b/src/pkg/runtime/float.c index f481519f6..42082e434 100644 --- a/src/pkg/runtime/float.c +++ b/src/pkg/runtime/float.c @@ -4,170 +4,7 @@ #include "runtime.h" -static uint64 uvnan = 0x7FF0000000000001ULL; -static uint64 uvinf = 0x7FF0000000000000ULL; -static uint64 uvneginf = 0xFFF0000000000000ULL; - -uint32 -runtime·float32tobits(float32 f) -{ - // The obvious cast-and-pointer code is technically - // not valid, and gcc miscompiles it. Use a union instead. - union { - float32 f; - uint32 i; - } u; - u.f = f; - return u.i; -} - -uint64 -runtime·float64tobits(float64 f) -{ - // The obvious cast-and-pointer code is technically - // not valid, and gcc miscompiles it. Use a union instead. - union { - float64 f; - uint64 i; - } u; - u.f = f; - return u.i; -} - -float64 -runtime·float64frombits(uint64 i) -{ - // The obvious cast-and-pointer code is technically - // not valid, and gcc miscompiles it. Use a union instead. - union { - float64 f; - uint64 i; - } u; - u.i = i; - return u.f; -} - -float32 -runtime·float32frombits(uint32 i) -{ - // The obvious cast-and-pointer code is technically - // not valid, and gcc miscompiles it. Use a union instead. - union { - float32 f; - uint32 i; - } u; - u.i = i; - return u.f; -} - -bool -runtime·isInf(float64 f, int32 sign) -{ - uint64 x; - - x = runtime·float64tobits(f); - if(sign == 0) - return x == uvinf || x == uvneginf; - if(sign > 0) - return x == uvinf; - return x == uvneginf; -} - -float64 -runtime·NaN(void) -{ - return runtime·float64frombits(uvnan); -} - -bool -runtime·isNaN(float64 f) -{ - uint64 x; - - x = runtime·float64tobits(f); - return ((uint32)(x>>52) & 0x7FF) == 0x7FF && !runtime·isInf(f, 0); -} - -float64 -runtime·Inf(int32 sign) -{ - if(sign >= 0) - return runtime·float64frombits(uvinf); - else - return runtime·float64frombits(uvneginf); -} - -enum -{ - MASK = 0x7ffL, - SHIFT = 64-11-1, - BIAS = 1022L, -}; - -float64 -runtime·frexp(float64 d, int32 *ep) -{ - uint64 x; - - if(d == 0) { - *ep = 0; - return 0; - } - x = runtime·float64tobits(d); - *ep = (int32)((x >> SHIFT) & MASK) - BIAS; - x &= ~((uint64)MASK << SHIFT); - x |= (uint64)BIAS << SHIFT; - return runtime·float64frombits(x); -} - -float64 -runtime·ldexp(float64 d, int32 e) -{ - uint64 x; - - if(d == 0) - return 0; - x = runtime·float64tobits(d); - e += (int32)(x >> SHIFT) & MASK; - if(e <= 0) - return 0; /* underflow */ - if(e >= MASK){ /* overflow */ - if(d < 0) - return runtime·Inf(-1); - return runtime·Inf(1); - } - x &= ~((uint64)MASK << SHIFT); - x |= (uint64)e << SHIFT; - return runtime·float64frombits(x); -} - -float64 -runtime·modf(float64 d, float64 *ip) -{ - float64 dd; - uint64 x; - int32 e; - - if(d < 1) { - if(d < 0) { - d = runtime·modf(-d, ip); - *ip = -*ip; - return -d; - } - *ip = 0; - return d; - } - - x = runtime·float64tobits(d); - e = (int32)((x >> SHIFT) & MASK) - BIAS; - - /* - * Keep the top 11+e bits; clear the rest. - */ - if(e <= 64-11) - x &= ~(((uint64)1 << (64LL-11LL-e))-1); - dd = runtime·float64frombits(x); - *ip = dd; - return d - dd; -} - +// used as float64 via runtime· names +uint64 ·nan = 0x7FF8000000000001ULL; +uint64 ·posinf = 0x7FF0000000000000ULL; +uint64 ·neginf = 0xFFF0000000000000ULL; |