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60 lines
1.5 KiB
60 lines
1.5 KiB
#include "src/lib/memory.h"
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#include "src/lib/layout.h"
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#include "src/lib/util.h"
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#ifdef KERNEL
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#define HEAP_VIRTUAL_BASE KERNEL_VIRTUAL_HEAP
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#else
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#define HEAP_VIRTUAL_BASE USER_VIRTUAL_HEAP
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#endif
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typedef struct free_chunk {
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uint64_t size; // header + data
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struct free_chunk *next;
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} free_chunk_t;
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static free_chunk_t *free_list;
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void *memory_allocate(uint64_t size) {
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if (!free_list) {
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free_list = (free_chunk_t *)HEAP_VIRTUAL_BASE;
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free_list->size = HEAP_SIZE;
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free_list->next = NUL;
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}
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size = sizeof(free_chunk_t) + ((size + 7) & (uint64_t)~7);
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free_chunk_t *prev = NUL;
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free_chunk_t *curr = free_list;
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while (curr) {
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if (curr->size >= size + (sizeof(free_chunk_t) + 8)) {
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free_chunk_t *remainder = (free_chunk_t *)((uint8_t *)curr + size);
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remainder->size = curr->size - size;
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remainder->next = curr->next;
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curr->size = size;
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curr->next = remainder;
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}
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if (curr->size >= size) {
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if (prev) {
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prev->next = curr->next;
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} else {
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free_list = curr->next;
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}
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void *result = (void *)((uint8_t *)curr + sizeof(free_chunk_t));
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memory_set(0, size - sizeof(free_chunk_t), result);
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return result;
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}
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prev = curr;
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curr = curr->next;
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}
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return NUL;
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}
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void memory_free(void *pointer) {
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free_chunk_t *chunk = (free_chunk_t *)((uint8_t *)pointer - sizeof(free_chunk_t));
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chunk->next = free_list;
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free_list = chunk;
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// TODO Merge adjacent free chunks.
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}
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