URL https://opencores.org/ocsvn/c0or1k/c0or1k/trunk

Subversion Repositories c0or1k

[/] [c0or1k/] [trunk/] [conts/] [posix/] [mm0/] [tests/] [idpool_test/] [bit.c] - Blame information for rev 2

Details | Compare with Previous | View Log


/*
 * Bit manipulation functions.
 *
 * Copyright (C) 2007 Bahadir Balban
 */
#include "bit.h"
#include <stdio.h>
 
/* Emulation of ARM's CLZ (count leading zeroes) instruction */
unsigned int __clz(unsigned int bitvector)
{
        unsigned int x = 0;
        while((!(bitvector & ((unsigned)1 << 31))) && (x < 32)) {
                bitvector <<= 1;
                x++;
        }
        return x;
}
 
int find_and_set_first_free_bit(u32 *word, unsigned int limit)
{
        int success = 0;
        int i;
 
        for(i = 0; i < limit; i++) {
                /* Find first unset bit */
                if (!(word[BITWISE_GETWORD(i)] & BITWISE_GETBIT(i))) {
                        /* Set it */
                        word[BITWISE_GETWORD(i)] |= BITWISE_GETBIT(i);
                        success = 1;
                        break;
                }
        }
 
        /* Return bit just set */
        if (success)
                return i;
        else
                return -1;
}
 
int find_and_set_first_free_contig_bits(u32 *word, unsigned int limit,
                                        int nbits)
{
        int i = 0, first = 0, last = 0, found = 0;
 
        /* Can't allocate more than the limit */
        if (nbits > limit)
                return -1;
 
        /* This is a state machine that checks n contiguous free bits. */
        while (i < limit) {
                first = i;
                last  = i;
                while (!(word[BITWISE_GETWORD(last)] & BITWISE_GETBIT(last))) {
                        last++;
                        i++;
                        if (last == first + nbits) {
                                found = 1;
                                break;
                        }
                        if (i == limit)
                                break;
                }
                if (found)
                        break;
                i++;
        }
 
        /* If found, set the bits */
        if (found) {
                for (int x = first; x < first + nbits; x++)
                        word[BITWISE_GETWORD(x)] |= BITWISE_GETBIT(x);
                return first;
        } else
                return -1;
}
 
int check_and_clear_bit(u32 *word, int bit)
{
        /* Check that bit was set */
        if (word[BITWISE_GETWORD(bit)] & BITWISE_GETBIT(bit)) {
                word[BITWISE_GETWORD(bit)] &= ~BITWISE_GETBIT(bit);
                return 0;
        } else {
                printf("Trying to clear already clear bit\n");
                return -1;
        }
}
 
int check_and_clear_contig_bits(u32 *word, int first, int nbits)
{
        for (int i = first; i < first + nbits; i++)
                if (check_and_clear_bit(word, i) < 0)
                        return -1;
        return 0;
}
 

Line No.	Rev	Author	Line
1	2	drasko	`/*`
2			`* Bit manipulation functions.`
3			`*`
4			`* Copyright (C) 2007 Bahadir Balban`
5			`*/`
6			`#include "bit.h"`
7			`#include <stdio.h>`
8
9			`/* Emulation of ARM's CLZ (count leading zeroes) instruction */`
10			`unsigned int __clz(unsigned int bitvector)`
11			`{`
12			`unsigned int x = 0;`
13			`while((!(bitvector & ((unsigned)1 << 31))) && (x < 32)) {`
14			`bitvector <<= 1;`
15			`x++;`
16			`}`
17			`return x;`
18			`}`
19
20			`int find_and_set_first_free_bit(u32 *word, unsigned int limit)`
21			`{`
22			`int success = 0;`
23			`int i;`
24
25			`for(i = 0; i < limit; i++) {`
26			`/* Find first unset bit */`
27			`if (!(word[BITWISE_GETWORD(i)] & BITWISE_GETBIT(i))) {`
28			`/* Set it */`
29			`word[BITWISE_GETWORD(i)] \|= BITWISE_GETBIT(i);`
30			`success = 1;`
31			`break;`
32			`}`
33			`}`
34
35			`/* Return bit just set */`
36			`if (success)`
37			`return i;`
38			`else`
39			`return -1;`
40			`}`
41
42			`int find_and_set_first_free_contig_bits(u32 *word, unsigned int limit,`
43			`int nbits)`
44			`{`
45			`int i = 0, first = 0, last = 0, found = 0;`
46
47			`/* Can't allocate more than the limit */`
48			`if (nbits > limit)`
49			`return -1;`
50
51			`/* This is a state machine that checks n contiguous free bits. */`
52			`while (i < limit) {`
53			`first = i;`
54			`last = i;`
55			`while (!(word[BITWISE_GETWORD(last)] & BITWISE_GETBIT(last))) {`
56			`last++;`
57			`i++;`
58			`if (last == first + nbits) {`
59			`found = 1;`
60			`break;`
61			`}`
62			`if (i == limit)`
63			`break;`
64			`}`
65			`if (found)`
66			`break;`
67			`i++;`
68			`}`
69
70			`/* If found, set the bits */`
71			`if (found) {`
72			`for (int x = first; x < first + nbits; x++)`
73			`word[BITWISE_GETWORD(x)] \|= BITWISE_GETBIT(x);`
74			`return first;`
75			`} else`
76			`return -1;`
77			`}`
78
79			`int check_and_clear_bit(u32 *word, int bit)`
80			`{`
81			`/* Check that bit was set */`
82			`if (word[BITWISE_GETWORD(bit)] & BITWISE_GETBIT(bit)) {`
83			`word[BITWISE_GETWORD(bit)] &= ~BITWISE_GETBIT(bit);`
84			`return 0;`
85			`} else {`
86			`printf("Trying to clear already clear bit\n");`
87			`return -1;`
88			`}`
89			`}`
90
91			`int check_and_clear_contig_bits(u32 *word, int first, int nbits)`
92			`{`
93			`for (int i = first; i < first + nbits; i++)`
94			`if (check_and_clear_bit(word, i) < 0)`
95			`return -1;`
96			`return 0;`
97			`}`
98

Browse

Tools

Subversion Repositories c0or1k

[/] [c0or1k/] [trunk/] [conts/] [posix/] [mm0/] [tests/] [idpool_test/] [bit.c] - Blame information for rev 2