1 #include "Python.h" 2 3 #ifdef X87_DOUBLE_ROUNDING 4 /* On x86 platforms using an x87 FPU, this function is called from the 5 Py_FORCE_DOUBLE macro (defined in pymath.h) to force a floating-point 6 number out of an 80-bit x87 FPU register and into a 64-bit memory location, 7 thus rounding from extended precision to double precision. */ _Py_force_double(double x)8double _Py_force_double(double x) 9 { 10 volatile double y; 11 y = x; 12 return y; 13 } 14 #endif 15 16 #ifdef HAVE_GCC_ASM_FOR_X87 17 18 /* inline assembly for getting and setting the 387 FPU control word on 19 gcc/x86 */ 20 _Py_get_387controlword(void)21unsigned short _Py_get_387controlword(void) { 22 unsigned short cw; 23 __asm__ __volatile__ ("fnstcw %0" : "=m" (cw)); 24 return cw; 25 } 26 _Py_set_387controlword(unsigned short cw)27void _Py_set_387controlword(unsigned short cw) { 28 __asm__ __volatile__ ("fldcw %0" : : "m" (cw)); 29 } 30 31 #endif 32 33 34 #ifndef HAVE_HYPOT hypot(double x,double y)35double hypot(double x, double y) 36 { 37 double yx; 38 39 x = fabs(x); 40 y = fabs(y); 41 if (x < y) { 42 double temp = x; 43 x = y; 44 y = temp; 45 } 46 if (x == 0.) 47 return 0.; 48 else { 49 yx = y/x; 50 return x*sqrt(1.+yx*yx); 51 } 52 } 53 #endif /* HAVE_HYPOT */ 54 55 #ifndef HAVE_COPYSIGN 56 double copysign(double x,double y)57copysign(double x, double y) 58 { 59 /* use atan2 to distinguish -0. from 0. */ 60 if (y > 0. || (y == 0. && atan2(y, -1.) > 0.)) { 61 return fabs(x); 62 } else { 63 return -fabs(x); 64 } 65 } 66 #endif /* HAVE_COPYSIGN */ 67 68 #ifndef HAVE_ROUND 69 double round(double x)70round(double x) 71 { 72 double absx, y; 73 absx = fabs(x); 74 y = floor(absx); 75 if (absx - y >= 0.5) 76 y += 1.0; 77 return copysign(y, x); 78 } 79 #endif /* HAVE_ROUND */ 80