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. */ |
8 | double _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 |
23 | unsigned short _Py_get_387controlword(void) { |
24 | unsigned short cw; |
25 | __asm__ __volatile__ ("fnstcw %0" : "=m" (cw)); |
26 | return cw; |
27 | } |
28 | |
29 | void _Py_set_387controlword(unsigned short cw) { |
30 | __asm__ __volatile__ ("fldcw %0" : : "m" (cw)); |
31 | } |
32 | |
33 | #endif |
34 | |
35 | |
36 | #ifndef HAVE_HYPOT |
37 | double 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 |
59 | copysign(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 |
72 | round(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 | |