mirror of
https://github.com/isometimes/rpi4-osdev
synced 2024-09-19 21:32:58 +00:00
49 lines
1 KiB
C
49 lines
1 KiB
C
// Define the heap
|
|
|
|
extern unsigned char _end[];
|
|
// unsigned char *HEAP_START = &_end[0]; // End of kernel
|
|
|
|
unsigned char *HEAP_START = (unsigned char *)0x400000; // Top of stack
|
|
unsigned int HEAP_SIZE = 0x30000000; // Max heap size is 768Mb
|
|
unsigned char *HEAP_END;
|
|
|
|
// Set up some static globals
|
|
|
|
static unsigned char *freeptr;
|
|
static unsigned int bytes_allocated = 0;
|
|
|
|
void mem_init()
|
|
{
|
|
// Align the start of heap to an 8-byte boundary
|
|
|
|
if ((long)HEAP_START % 8 != 0) {
|
|
HEAP_START += 8 - ((long)HEAP_START % 8);
|
|
}
|
|
HEAP_END = (unsigned char *)(HEAP_START + HEAP_SIZE);
|
|
|
|
freeptr = HEAP_START;
|
|
}
|
|
|
|
void *malloc(unsigned int size)
|
|
{
|
|
if (size > 0) {
|
|
void *allocated = freeptr;
|
|
if ((long)allocated % 8 != 0) {
|
|
allocated += 8 - ((long)allocated % 8);
|
|
}
|
|
|
|
if ((unsigned char *)(allocated + size) > HEAP_END) {
|
|
return 0;
|
|
} else {
|
|
freeptr += size;
|
|
bytes_allocated += size;
|
|
|
|
return allocated;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
void free(void *ptr) {
|
|
// TODO
|
|
}
|