marCsweep/vm.c

76 lines
1.7 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include "gc.h"
#include "vm.h"
struct virtualMachine *initVM() {
struct virtualMachine *vm = malloc(sizeof(struct virtualMachine));
vm->stackSize = 0;
vm->refCount = 0;
vm->refMax = GC_THRESHOLD;
vm->head = NULL;
return vm;
}
void push(struct virtualMachine *vm, struct garbageObject *value) {
if (vm->stackSize >= STACK_MAX) {
fprintf(stderr, "ERROR: push(): refusing to overflow the stack!\n");
return;
}
vm->stack[vm->stackSize++] = value;
}
struct garbageObject *pop(struct virtualMachine *vm) {
if (vm->stackSize < 0) {
fprintf(stderr, "ERROR: pop(): Stack size cannot be negative!");
return NULL;
}
return vm->stack[--vm->stackSize];
}
struct garbageObject *initGarbage(struct virtualMachine *vm,
enum garbageData type) {
if (vm->refCount >= vm->refMax) {
collect(vm);
}
struct garbageObject *obj = malloc(sizeof(struct garbageObject));
if (obj == NULL) {
fprintf(stderr, "initGarbage(): Allocation failure!");
return obj;
}
obj->type = type;
obj->mark = 0;
obj->next = vm->head;
vm->head = obj;
vm->refCount++;
return obj;
}
void pushInt(struct virtualMachine *vm, int value) {
struct garbageObject *obj = initGarbage(vm, GARBAGE_INT);
if (obj == NULL) {
fprintf(stderr, "pushInt(): Unable to create GARBAGE_INT - out of memory?");
}
obj->value = value;
push(vm, obj);
}
struct garbageObject *pushPair(struct virtualMachine *vm) {
struct garbageObject *obj = initGarbage(vm, GARBAGE_PAIR);
if (obj == NULL) {
fprintf(stderr,
"pushPair(): Unable to create GARBAGE_PAIR - out of memory?");
}
obj->tail = pop(vm);
obj->head = pop(vm);
push(vm, obj);
return obj;
}