| #include "libm.h" |
| |
| #if FLT_EVAL_METHOD==0 || FLT_EVAL_METHOD==1 |
| #define EPS DBL_EPSILON |
| #elif FLT_EVAL_METHOD==2 |
| #define EPS LDBL_EPSILON |
| #endif |
| static const double_t toint = 1/EPS; |
| |
| double floor(double x) |
| { |
| union {double f; uint64_t i;} u = {x}; |
| int e = u.i >> 52 & 0x7ff; |
| double_t y; |
| |
| if (e >= 0x3ff+52 || x == 0) |
| return x; |
| /* y = int(x) - x, where int(x) is an integer neighbor of x */ |
| if (u.i >> 63) |
| y = x - toint + toint - x; |
| else |
| y = x + toint - toint - x; |
| /* special case because of non-nearest rounding modes */ |
| if (e <= 0x3ff-1) { |
| FORCE_EVAL(y); |
| return u.i >> 63 ? -1 : 0; |
| } |
| if (y > 0) |
| return x + y - 1; |
| return x + y; |
| } |
