src/kernel/lib/memory.c


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#include <stddef.h>
#include <stdint.h>

void *memcpy(void *dest, const void *src, size_t count)
{
	const char *sp = (const char *)src;
	char *dp = (char *)dest;
	for (; count != 0; count--)
		*dp++ = *sp++;
	return dest;
}

void *memset(void *dest, char val, size_t count)
{
	char *temp = (char *)dest;
	for (; count != 0; count--)
		*temp++ = val;
	return dest;
}

int memcmp(const void *a_ptr, const void *b_ptr, size_t size)
{
	const unsigned char *a = (const unsigned char *)a_ptr;
	const unsigned char *b = (const unsigned char *)b_ptr;
	for (size_t i = 0; i < size; i++) {
		if (a[i] < b[i])
			return -1;
		else if (b[i] < a[i])
			return 1;
	}
	return 0;
}

uint32_t total_memory;

struct memory_entry {
	uint64_t base;
	uint64_t length;
	uint32_t type;
} __attribute__((packed));

struct memory_entry *memory_get_entries()
{
	return (struct memory_entry *)0xA000;
}

void memory_init()
{
	uint64_t max_base = 0;
	uint64_t max_length = 0;
	for (struct memory_entry *i = memory_get_entries(); i->type; i++) {
		if (i->type == 1 && i->base > max_base) {
			max_base = i->base;
			max_length = i->length;
		}
	}
	total_memory = (uint32_t)(max_base + max_length);
	total_memory /= 1024;
}

uint32_t memory_get_free()
{
	return total_memory; // - paging_get_used_pages() * 4;
}

uint32_t memory_get_all()
{
	return total_memory;
}