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#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include "array.h"
#include "stack.h"
#include "vm.h"
void
vm_init(vm_t *vm)
{
assert(vm);
vm->stack = (stack_t) {
.capacity = STACK_CAPACITY,
.size = 0,
.data = calloc(sizeof(int), STACK_CAPACITY)
};
vm->call_stack = (stack_t) {
.capacity = 3000,
.size = 0,
.data = calloc(sizeof(int), 3000)
};
vm->heap = calloc(sizeof(int), HEAP_CAPACITY);
vm->labels = array(label_t);
}
void
vm_run(vm_t *vm, inst_t *insts)
{
size_t program_size = array_length(insts);
// resolve lables
for (size_t ip = 0; ip < program_size; ++ip) {
if (insts[ip].type == INST_LABEL) {
int name = insts[ip].operand;
label_t label = { .name = name, .index = ip };
array_append(vm->labels, label);
}
}
// resolve jumps
for (size_t ip = 0; ip < program_size; ++ip) {
switch (insts[ip].type) {
case INST_CALL:
case INST_JMP:
case INST_JMPN:
case INST_JMPZ: {
int label_name = insts[ip].operand;
size_t i = 0;
size_t labels_size = array_length(vm->labels);
for (; i < labels_size; ++i) {
if (vm->labels[i].name == label_name) {
insts[ip].operand = vm->labels[i].index;
break;
}
}
assert(i < labels_size);
}
default: break;
}
}
// run
for (size_t ip = 0; ip < program_size; ++ip) {
switch (insts[ip].type) {
case INST_PUSH: {
stack_push(&vm->stack, insts[ip].operand);
break;
}
case INST_DUP: {
stack_push(&vm->stack, vm->stack.data[vm->stack.size - 1]);
break;
}
case INST_COPY: {
int operand = insts[ip].operand;
stack_push(&vm->stack, vm->stack.data[vm->stack.size - 1 - operand]);
break;
}
case INST_SWAP: {
int a = stack_pop(&vm->stack);
int b = stack_pop(&vm->stack);
stack_push(&vm->stack, a);
stack_push(&vm->stack, b);
break;
}
case INST_DROP: {
stack_pop(&vm->stack);
break;
}
case INST_SLIDE: {
int operand = insts[ip].operand;
int top = stack_pop(&vm->stack);
while (operand-- > 0) {
stack_pop(&vm->stack);
}
stack_push(&vm->stack, top);
break;
}
case INST_ADD: {
int lhs = stack_pop(&vm->stack);
int rhs = stack_pop(&vm->stack);
stack_push(&vm->stack, lhs + rhs);
break;
}
case INST_SUB: {
int rhs = stack_pop(&vm->stack);
int lhs = stack_pop(&vm->stack);
stack_push(&vm->stack, lhs - rhs);
break;
}
case INST_MUL: {
int rhs = stack_pop(&vm->stack);
int lhs = stack_pop(&vm->stack);
stack_push(&vm->stack, lhs * rhs);
break;
}
case INST_DIV: {
int rhs = stack_pop(&vm->stack);
int lhs = stack_pop(&vm->stack);
stack_push(&vm->stack, lhs / rhs);
break;
}
case INST_MOD: {
int rhs = stack_pop(&vm->stack);
int lhs = stack_pop(&vm->stack);
stack_push(&vm->stack, lhs % rhs);
break;
}
case INST_STORE: {
int value = stack_pop(&vm->stack);
int address = stack_pop(&vm->stack);
vm->heap[address] = value;
break;
}
case INST_LOAD: {
int address = stack_pop(&vm->stack);
stack_push(&vm->stack, vm->heap[address]);
break;
}
case INST_CALL: {
stack_push(&vm->call_stack, ip + 1);
ip = insts[ip].operand;
break;
}
case INST_RET: {
ip = stack_pop(&vm->call_stack);
break;
}
case INST_JMP: {
ip = insts[ip].operand;
break;
}
case INST_JMPZ: {
int value = stack_pop(&vm->stack);
if (value == 0) {
ip = insts[ip].operand;
}
break;
}
case INST_JMPN: {
int value = stack_pop(&vm->stack);
if (value < 0) {
ip = insts[ip].operand;
}
break;
}
case INST_PRINTI: {
int value = stack_pop(&vm->stack);
printf("%d", value);
break;
}
case INST_PRINTC: {
int value = stack_pop(&vm->stack);
printf("%c", value);
break;
}
case INST_READI: {
int address = stack_pop(&vm->stack);
scanf("%d", vm->heap + address);
break;
}
case INST_READC: {
int address = stack_pop(&vm->stack);
vm->heap[address] = getchar();
break;
}
case INST_END: {
return;
}
case INST_LABEL: {
break;
}
default: {
assert(0 && "Unsupported instruction");
break;
}
}
}
}
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