1#include <limits.h> 2#include "libm.h" 3 4#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024 5int ilogbl(long double x) 6{ 7 return ilogb(x); 8} 9#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 10int ilogbl(long double x) 11{ 12 #pragma STDC FENV_ACCESS ON 13 union ldshape u = {x}; 14 uint64_t m = u.i.m; 15 int e = u.i.se & 0x7fff; 16 17 if (!e) { 18 if (m == 0) { 19 FORCE_EVAL(0/0.0f); 20 return FP_ILOGB0; 21 } 22 /* subnormal x */ 23 for (e = -0x3fff+1; m>>63 == 0; e--, m<<=1); 24 return e; 25 } 26 if (e == 0x7fff) { 27 FORCE_EVAL(0/0.0f); 28 return m<<1 ? FP_ILOGBNAN : INT_MAX; 29 } 30 return e - 0x3fff; 31} 32#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384 33int ilogbl(long double x) 34{ 35 #pragma STDC FENV_ACCESS ON 36 union ldshape u = {x}; 37 int e = u.i.se & 0x7fff; 38 39 if (!e) { 40 if (x == 0) { 41 FORCE_EVAL(0/0.0f); 42 return FP_ILOGB0; 43 } 44 /* subnormal x */ 45 x *= 0x1p120; 46 return ilogbl(x) - 120; 47 } 48 if (e == 0x7fff) { 49 FORCE_EVAL(0/0.0f); 50 u.i.se = 0; 51 return u.f ? FP_ILOGBNAN : INT_MAX; 52 } 53 return e - 0x3fff; 54} 55#endif 56