1 | // -*- Mode: C -*- |
---|
2 | // |
---|
3 | // Cforall Version 1.0.0 Copyright (C) 2020 University of Waterloo |
---|
4 | // |
---|
5 | // The contents of this file are covered under the licence agreement in the |
---|
6 | // file "LICENCE" distributed with Cforall. |
---|
7 | // |
---|
8 | // bitmanip.hfa -- |
---|
9 | // |
---|
10 | // Author : Peter A. Buhr |
---|
11 | // Created On : Sat Mar 14 18:12:27 2020 |
---|
12 | // Last Modified By : Peter A. Buhr |
---|
13 | // Last Modified On : Mon Apr 6 22:17:19 2020 |
---|
14 | // Update Count : 78 |
---|
15 | // |
---|
16 | |
---|
17 | #pragma once |
---|
18 | |
---|
19 | // Reference: Bit Twiddling Hacks: http://graphics.stanford.edu/%7Eseander/bithacks.html#CountBitsSetNaive |
---|
20 | |
---|
21 | // Bits are numbered 1-N. |
---|
22 | |
---|
23 | #include <assert.h> |
---|
24 | |
---|
25 | #define __bitsizeof( n ) (sizeof(n) * __CHAR_BIT__) |
---|
26 | |
---|
27 | static inline { |
---|
28 | // Count leading 0 bits. |
---|
29 | unsigned int leading0s( unsigned char n ) { return n != 0 ? __builtin_clz( n ) - (__bitsizeof(unsigned int) - __bitsizeof(n)) : __bitsizeof(n); } |
---|
30 | unsigned int leading0s( unsigned short int n ) { return n != 0 ? __builtin_clz( n ) - (__bitsizeof(unsigned int) - __bitsizeof(n)) : __bitsizeof(n); } |
---|
31 | unsigned int leading0s( unsigned int n ) { return n != 0 ? __builtin_clz( n ) : __bitsizeof(n); } |
---|
32 | unsigned int leading0s( unsigned long int n ) { return n != 0 ? __builtin_clzl( n ) : __bitsizeof(n); } |
---|
33 | unsigned int leading0s( unsigned long long int n ) { return n != 0 ? __builtin_clzll( n ) : __bitsizeof(n); } |
---|
34 | |
---|
35 | // Count trailing 0 bits. |
---|
36 | unsigned int trailing0s( unsigned char n ) { return n != 0 ? __builtin_ctz( n ) : __bitsizeof(n); } |
---|
37 | unsigned int trailing0s( unsigned short int n ) { return n != 0 ? __builtin_ctz( n ) : __bitsizeof(n); } |
---|
38 | unsigned int trailing0s( unsigned int n ) { return n != 0 ? __builtin_ctz( n ) : __bitsizeof(n); } |
---|
39 | unsigned int trailing0s( unsigned long int n ) { return n != 0 ? __builtin_ctzl( n ) : __bitsizeof(n); } |
---|
40 | unsigned int trailing0s( unsigned long long int n ) { return n != 0 ? __builtin_ctzll( n ) : __bitsizeof(n); } |
---|
41 | |
---|
42 | // Count all 1 bits. |
---|
43 | unsigned int all1s( unsigned char n ) { return __builtin_popcount( n ); } |
---|
44 | unsigned int all1s( unsigned short int n ) { return __builtin_popcount( n ); } |
---|
45 | unsigned int all1s( unsigned int n ) { return __builtin_popcount( n ); } |
---|
46 | unsigned int all1s( unsigned long int n ) { return __builtin_popcountl( n ); } |
---|
47 | unsigned int all1s( unsigned long long int n ) { return __builtin_popcountll( n ); } |
---|
48 | |
---|
49 | // Count all 0 bits. |
---|
50 | unsigned int all0s( unsigned char n ) { return __bitsizeof(n) - __builtin_popcount( n ); } |
---|
51 | unsigned int all0s( unsigned short int n ) { return __bitsizeof(n) - __builtin_popcount( n ); } |
---|
52 | unsigned int all0s( unsigned int n ) { return __bitsizeof(n) - __builtin_popcount( n ); } |
---|
53 | unsigned int all0s( unsigned long int n ) { return __bitsizeof(n) - __builtin_popcountl( n ); } |
---|
54 | unsigned int all0s( unsigned long long int n ) { return __bitsizeof(n) - __builtin_popcountll( n ); } |
---|
55 | |
---|
56 | // Find least significiant zero bit. (ffs) |
---|
57 | unsigned int low0( unsigned char n ) { return __builtin_ffs( (typeof(n))~n ); } |
---|
58 | unsigned int low0( unsigned short int n ) { return __builtin_ffs( (typeof(n))~n ); } |
---|
59 | unsigned int low0( unsigned int n ) { return __builtin_ffs( ~n ); } |
---|
60 | unsigned int low0( unsigned long int n ) { return __builtin_ffsl( ~n ); } |
---|
61 | unsigned int low0( unsigned long long int n ) { return __builtin_ffsll( ~n ); } |
---|
62 | |
---|
63 | // Find least significiant one bit. |
---|
64 | unsigned int low1( unsigned int n ) { return __builtin_ffs( n ); } |
---|
65 | unsigned int low1( unsigned long int n ) { return __builtin_ffsl( n ); } |
---|
66 | unsigned int low1( unsigned long long int n ) { return __builtin_ffsll( n ); } |
---|
67 | |
---|
68 | // Find most significiant zero bit. |
---|
69 | unsigned int high0( unsigned char n ) { return n != (typeof(n))-1 ? __bitsizeof(unsigned int) - __builtin_clz( (typeof(n))~n ) : 0; } |
---|
70 | unsigned int high0( unsigned short int n ) { return n != (typeof(n))-1 ? __bitsizeof(unsigned int) - __builtin_clz( (typeof(n))~n ) : 0; } |
---|
71 | unsigned int high0( unsigned int n ) { return n != -1 ? __bitsizeof(n) - __builtin_clz( ~n ) : 0; } |
---|
72 | unsigned int high0( unsigned long int n ) { return n != -1 ? __bitsizeof(n) - __builtin_clzl( ~n ) : 0; } |
---|
73 | unsigned int high0( unsigned long long int n ) { return n != -1 ? __bitsizeof(n) - __builtin_clzll( ~n ) : 0; } |
---|
74 | |
---|
75 | // Find most significiant one bit. |
---|
76 | unsigned int high1( unsigned char n ) { return n != 0 ? __bitsizeof(unsigned int) - __builtin_clz( n ) : 0; } |
---|
77 | unsigned int high1( unsigned short int n ) { return n != 0 ? __bitsizeof(unsigned int) - __builtin_clz( n ) : 0; } |
---|
78 | unsigned int high1( unsigned int n ) { return n != 0 ? __bitsizeof(n) - __builtin_clz( n ) : 0; } |
---|
79 | unsigned int high1( unsigned long int n ) { return n != 0 ? __bitsizeof(n) - __builtin_clzl( n ) : 0; } |
---|
80 | unsigned int high1( unsigned long long int n ) { return n != 0 ? __bitsizeof(n) - __builtin_clzll( n ) : 0; } |
---|
81 | |
---|
82 | // Check for power of 2, clears bits below value, rounding down to the next lower multiple of value. |
---|
83 | bool is_pow2( int value ) { return (value & (value - 1)) == 0; } |
---|
84 | bool is_pow2( unsigned long long int value ) { return (value & (value - 1)) == 0; } |
---|
85 | |
---|
86 | // Returns value aligned at the floor of align, clear bits above or equal to align, giving value % align. |
---|
87 | unsigned int floor2( unsigned int value, unsigned int align ) { assert( is_pow2( align ) ); return value & -align; } |
---|
88 | unsigned long long int floor2( unsigned long long int value, unsigned long long int align ) { assert( is_pow2( align ) ); return value & -align; } |
---|
89 | |
---|
90 | unsigned int floor( unsigned int value, unsigned int align ) { return value / align * align; } |
---|
91 | unsigned long long int floor( unsigned long long int value, unsigned long long int align ) { return value / align * align; } |
---|
92 | |
---|
93 | // Returns value aligned at the ceiling of align, negate, round down, negate is the same as round up. |
---|
94 | unsigned int ceiling2( unsigned int value, unsigned int align ) { assert( is_pow2( align ) ); return -floor2( -value, align ); } |
---|
95 | unsigned long long int ceiling2( unsigned long long int value, unsigned long long int align ) { assert( is_pow2( align ) ); return -floor2( -value, align ); } |
---|
96 | |
---|
97 | unsigned int ceiling( unsigned int value, unsigned int align ) { return (value + (align - 1)) / align; } |
---|
98 | unsigned long long int ceiling( unsigned long long int value, unsigned long long int align ) { return (value + (align - 1)) / align; } |
---|
99 | } // distribution |
---|
100 | |
---|
101 | // Local Variables: // |
---|
102 | // tab-width: 4 // |
---|
103 | // End: // |
---|