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Added 'math.c' for optimized math and bit operations

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This commit is contained in:
ngiddings
2022-08-23 08:41:53 -05:00
parent c36f65ce97
commit 21509be9bc
3 changed files with 77 additions and 19 deletions
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22
src/heap.c
View File

@@ -1,6 +1,7 @@
#include <stdbool.h>
#include "heap.h"
#include "mmgr.h"
#include "math.h"
#include "types/status.h"
#define AVAIL 0
@@ -23,23 +24,6 @@ struct heap_node_t
size_t state : 2;
} __attribute__ ((packed));
size_t ilog2(size_t n)
{
size_t m = n;
size_t count = 0;
bool isPowerOfTwo = true;
while(m)
{
if((m & 1) == 1 && m > 1)
{
isPowerOfTwo = false;
}
count++;
m >>= 1;
}
return count - (isPowerOfTwo ? 1 : 0);
}
size_t find_free_block(struct heap_t *heap, size_t height)
{
if(height > heap->tree_height)
@@ -95,7 +79,7 @@ int heap_contruct(struct heap_t *heap, void *base, void *start, size_t heap_size
heap->header = (struct heap_node_t*) start;
heap->heap_size = heap_size;
heap->block_size = block_size;
heap->tree_height = ilog2(heap_size / block_size);
heap->tree_height = llog2(heap_size / block_size);
size_t header_size = (heap_size / block_size) << 1;
for(size_t i = 1; i <= (heap_size / block_size) * 2; i++)
{
@@ -136,7 +120,7 @@ void *heap_allocate(struct heap_t *heap, size_t size)
{
size += heap->block_size - 1;
size -= size % heap->block_size;
size_t height = ilog2(size / heap->block_size);
size_t height = llog2(size / heap->block_size);
size_t index = find_free_block(heap, height);
if(index)
{

66
src/math.c Normal file
View File

@@ -0,0 +1,66 @@
#include "math.h"
int ilog2(unsigned int x)
{
#if defined __GNUC__
if(x <= 1)
return 0;
return 32 - __builtin_clzl(x - 1);
#else
static const int table[32] = {
0, 9, 1, 10, 13, 21, 2, 29,
11, 14, 16, 18, 22, 25, 3, 30,
8, 12, 20, 28, 15, 17, 24, 7,
19, 27, 23, 6, 26, 5, 4, 31};
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
return table[(x * 0x07C4ACDD) >> 27];
#endif
}
int llog2(unsigned long x)
{
#if (defined __GNUC__) && (__SIZEOF_LONG__ == 4)
if(x <= 1)
return 0;
return 32 - __builtin_clzl(x - 1);
#elif (defined __GNUC__) && (__SIZEOF_LONG__ == 8)
if(x <= 1)
return 0;
return 64 - __buildin_clzl(x - 1);
#elif __SIZEOF_LONG__ == 8
static const int table[64] = {
0, 58, 1, 59, 47, 53, 2, 60, 39, 48, 27, 54, 33, 42, 3, 61,
51, 37, 40, 49, 18, 28, 20, 55, 30, 34, 11, 43, 14, 22, 4, 62,
57, 46, 52, 38, 26, 32, 41, 50, 36, 17, 19, 29, 10, 13, 21, 56,
45, 25, 31, 35, 16, 9, 12, 44, 24, 15, 8, 23, 7, 6, 5, 63};
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
x |= x >> 32;
return table[(x * 0x03f6eaf2cd271461) >> 58];
#else
static const int table[32] = {
0, 9, 1, 10, 13, 21, 2, 29,
11, 14, 16, 18, 22, 25, 3, 30,
8, 12, 20, 28, 15, 17, 24, 7,
19, 27, 23, 6, 26, 5, 4, 31};
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
return table[(x * 0x07C4ACDD) >> 27];
#endif
}