diff options
Diffstat (limited to 'include/my_global.h')
| -rw-r--r-- | include/my_global.h | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/include/my_global.h b/include/my_global.h index 845ae042a42..f5a3016bb1e 100644 --- a/include/my_global.h +++ b/include/my_global.h @@ -324,6 +324,9 @@ C_MODE_END #ifdef HAVE_FLOAT_H #include <float.h> #endif +#ifdef HAVE_FENV_H +#include <fenv.h> /* For fesetround() */ +#endif #ifdef HAVE_SYS_TYPES_H #include <sys/types.h> @@ -484,8 +487,39 @@ typedef unsigned short ushort; #define set_bits(type, bit_count) (sizeof(type)*8 <= (bit_count) ? ~(type) 0 : ((((type) 1) << (bit_count)) - (type) 1)) #define array_elements(A) ((uint) (sizeof(A)/sizeof(A[0]))) #ifndef HAVE_RINT -#define rint(A) floor((A)+(((A) < 0)? -0.5 : 0.5)) -#endif +/** + All integers up to this number can be represented exactly as double precision + values (DBL_MANT_DIG == 53 for IEEE 754 hardware). +*/ +#define MAX_EXACT_INTEGER ((1LL << DBL_MANT_DIG) - 1) + +/** + rint(3) implementation for platforms that do not have it. + Always rounds to the nearest integer with ties being rounded to the nearest + even integer to mimic glibc's rint() behavior in the "round-to-nearest" + FPU mode. Hardware-specific optimizations are possible (frndint on x86). + Unlike this implementation, hardware will also honor the FPU rounding mode. +*/ + +static inline double rint(double x) +{ + double f, i; + f = modf(x, &i); + /* + All doubles with absolute values > MAX_EXACT_INTEGER are even anyway, + no need to check it. + */ + if (x > 0.0) + i += (double) ((f > 0.5) || (f == 0.5 && + i <= (double) MAX_EXACT_INTEGER && + (longlong) i % 2)); + else + i -= (double) ((f < -0.5) || (f == -0.5 && + i >= (double) -MAX_EXACT_INTEGER && + (longlong) i % 2)); + return i; +} +#endif /* HAVE_RINT */ /* Define some general constants */ #ifndef TRUE |