/src/Python-3.8.3/Python/pymath.c
Line | Count | Source |
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 | 2 | unsigned short _Py_get_387controlword(void) { |
24 | 2 | unsigned short cw; |
25 | 2 | __asm__ __volatile__ ("fnstcw %0" : "=m" (cw)); |
26 | 2 | return cw; |
27 | 2 | } |
28 | | |
29 | 4 | void _Py_set_387controlword(unsigned short cw) { |
30 | 4 | __asm__ __volatile__ ("fldcw %0" : : "m" (cw)); |
31 | 4 | } |
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 */ |