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vm/mm.c: remove base_addr variable, we can do the stuff with macros and pointer casts :)

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Henrik Hautakoski 2019-04-25 14:29:44 +02:00
parent 67a272b715
commit e92b7ee551
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GPG key ID: 839F3A7EAFAEAFAA
1 changed files with 11 additions and 10 deletions
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21
vm/mm.c
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@ -26,29 +26,30 @@
#define MEM_SIZE 65536 #define MEM_SIZE 65536
#endif #endif
// Get a WORD aligned (16-bit) address.
// Casts the 8-bit pointer (memory) to 16-bit (WORD) and add offset.
#define addr_align_word(offset) \
(((uint16_t*) memory) + (offset))
#define EXCEPTION_STRING "Runtime exception: Memory address '%u' is out of bounds.\n" #define EXCEPTION_STRING "Runtime exception: Memory address '%u' is out of bounds.\n"
int16_t* base_addr = NULL;
uint8_t *memory = NULL; uint8_t *memory = NULL;
#define __check_bounds(addr) \ #define __check_bounds(addr) \
if ((addr) > MEM_SIZE) { \ if ((addr) + 1 > MEM_SIZE) { \
fprintf(stderr, EXCEPTION_STRING, addr);\ fprintf(stderr, EXCEPTION_STRING, addr);\
exit(1); \ exit(1); \
} }
void mm_init() { void mm_init() {
base_addr = malloc(MEM_SIZE); memory = (uint8_t*) malloc(MEM_SIZE);
memory = (uint8_t*) base_addr;
} }
void mm_exit() { void mm_exit() {
if (base_addr) { if (memory) {
free(base_addr); free(memory);
base_addr = NULL;
memory = NULL; memory = NULL;
} }
} }
@ -57,12 +58,12 @@ void mm_sw(uint16_t addr, int16_t value) {
__check_bounds(addr); __check_bounds(addr);
base_addr[addr] = value; *addr_align_word(addr) = value;
} }
int16_t mm_lw(uint16_t addr) { int16_t mm_lw(uint16_t addr) {
__check_bounds(addr); __check_bounds(addr);
return base_addr[addr]; return *addr_align_word(addr);
} }