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 #ifdef _Py_MEMORY_SANITIZER 21 __attribute__((no_sanitize_memory)) 22 #endif _Py_get_387controlword(void)23unsigned short _Py_get_387controlword(void) { 24 unsigned short cw; 25 __asm__ __volatile__ ("fnstcw %0" : "=m" (cw)); 26 return cw; 27 } 28 _Py_set_387controlword(unsigned short cw)29void _Py_set_387controlword(unsigned short cw) { 30 __asm__ __volatile__ ("fldcw %0" : : "m" (cw)); 31 } 32 33 #endif 34 35 36 #ifndef HAVE_HYPOT hypot(double x,double y)37double hypot(double x, double y) 38 { 39 double yx; 40 41 x = fabs(x); 42 y = fabs(y); 43 if (x < y) { 44 double temp = x; 45 x = y; 46 y = temp; 47 } 48 if (x == 0.) 49 return 0.; 50 else { 51 yx = y/x; 52 return x*sqrt(1.+yx*yx); 53 } 54 } 55 #endif /* HAVE_HYPOT */ 56 57 #ifndef HAVE_COPYSIGN 58 double copysign(double x,double y)59copysign(double x, double y) 60 { 61 /* use atan2 to distinguish -0. from 0. */ 62 if (y > 0. || (y == 0. && atan2(y, -1.) > 0.)) { 63 return fabs(x); 64 } else { 65 return -fabs(x); 66 } 67 } 68 #endif /* HAVE_COPYSIGN */ 69 70 #ifndef HAVE_ROUND 71 double round(double x)72round(double x) 73 { 74 double absx, y; 75 absx = fabs(x); 76 y = floor(absx); 77 if (absx - y >= 0.5) 78 y += 1.0; 79 return copysign(y, x); 80 } 81 #endif /* HAVE_ROUND */ 82