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#include "vm.h"
#include <math.h>
#include <string.h>
#include "dyn_arr.h"
#include "us_debug.h"
#include "uscript.h"
struct vm vm;
void init_vm(void)
{
vm.objs = da_create(struct us_val, 128);
vm.cf = vm.cf_stack;
vm.stacktop = vm.stack;
}
void deinit_vm(void)
{
for (int i = 0; i < da_len(vm.objs); i++) {
free_val(vm.objs[i]);
}
da_clear(vm.objs); // not needed, but makes me feel better :)
da_free(vm.objs);
}
static
bool as_bool(struct us_val v)
{
if (v.type == VAL_ZILCH)
return false;
if (v.type == VAL_BOOL)
return get_bool(v);
return true;
}
static
struct us_str *concat(struct us_val a, struct us_val b)
{
int a_len;
char *a_str = val_to_str(a, &a_len);
int b_len;
char *b_str = val_to_str(b, &b_len);
int len = a_len + b_len;
char *chars = mem_alloc(sizeof(char) * (len + 1));
memcpy(chars, a_str, a_len);
memcpy(chars + a_len, b_str, b_len);
chars[len] = '\0';
mem_free(a_str);
mem_free(b_str);
return take_str(chars, len);
}
static
u16 read_short(struct us_proto *proto, int *i)
{
return (u16)(proto->bytecode[++*i] << 8) | proto->bytecode[++*i];
}
static
void close_upvals(struct us_val *to)
{
struct us_upval *upval = vm.open_upvals;
while (upval && upval->loc > to) {
upval->closed = *upval->loc;
upval->loc = &upval->closed;
upval = upval->next;
}
vm.open_upvals = upval;
}
void us_exec(struct us_func *func)
{
#define read_byte() (func->proto->bytecode[++i])
#define read_const() (func->proto->constants[read_byte()])
vm.cf++;
vm.cf->func = func;
vm.cf->stackbot = vm.stacktop - func->proto->argc;
for (int i = 0; i < da_len(func->proto->bytecode); i++) {
enum bytecode instruction = func->proto->bytecode[i];
// putc('>', stderr);
// for (struct us_val *val = vm.stack; val < vm.stacktop; val++) {
// char *val_str = val_to_str(*val, NULL);
// if (val == vm.cf->stackbot - 1)
// fprintf(stderr, " %s >", val_str);
// else
// fprintf(stderr, " %s |", val_str);
// mem_free(val_str);
// }
// putc('\n', stderr);
// putc('>', stderr);
// print_instruction(func->proto, i);
switch (instruction) {
case BC_LOAD:
vm_push(read_const());
break;
case BC_LOAD_FUNC: {
struct us_proto *proto = get_proto(read_const());
struct us_func *new_func = create_func(proto);
for (int j = 0; j < proto->upvalc; j++) {
u8 is_local = read_byte();
u8 index = read_byte();
if (is_local) {
struct us_upval *upval = create_upval(
vm.cf->stackbot + index
);
upval->next = vm.open_upvals;
vm.open_upvals = upval;
new_func->upvals[j] = upval;
} else {
new_func->upvals[j] =
func->upvals[index];
}
}
vm_push(wrap_func(new_func));
break;
}
case BC_SMALL_INT:
vm_push(create_num(read_byte()));
break;
case BC_FALSE: vm_push(create_bool(false)); break;
case BC_TRUE: vm_push(create_bool(true)); break;
case BC_ZILCH: vm_push(create_zilch()); break;
case BC_ARR: {
struct us_arr *arr = create_arr();
u8 arr_len = read_byte();
// elements are in reverse order, so we add them in the
// correct order, and pop them all off at the end
for (u8 i = 0; i < arr_len; i++) {
da_append(
struct us_val,
&arr->e,
*(vm.stacktop - arr_len + i)
);
}
vm.stacktop -= arr_len;
vm_push(wrap_arr(arr));
break;
}
case BC_SET_LOCAL:
vm.cf->stackbot[read_byte()] = vm_peek();
break;
case BC_GET_LOCAL:
vm_push(vm.cf->stackbot[read_byte()]);
break;
case BC_GET_UPVAL:
vm_push(*func->upvals[read_byte()]->loc);
break;
case BC_SET_UPVAL:
*func->upvals[read_byte()]->loc = vm_peek();
break;
case BC_SET_INDEX: {
struct us_val set_val = vm_pop();
struct us_val idx_val = vm_pop();
struct us_val arr_val = vm_pop();
if (idx_val.type != VAL_NUM)
log_fatal(1, "index type must be number");
if (arr_val.type != VAL_ARR)
log_fatal(1, "only arrays can be indexed");
int idx = (int)get_num(idx_val);
struct us_arr *arr = get_arr(arr_val);
if (idx < 0)
idx += da_len(arr->e);
if (idx < 0 || idx >= da_len(arr->e)) {
log_fatal(
1,
"index out of range (%d/%d)",
idx,
da_len(arr->e) - 1
);
}
arr->e[idx] = set_val;
vm_push(set_val);
break;
}
case BC_GET_INDEX: {
struct us_val idx_val = vm_pop();
struct us_val arr_val = vm_pop();
if (idx_val.type != VAL_NUM)
log_fatal(1, "index type must be number");
if (arr_val.type != VAL_ARR)
log_fatal(1, "only arrays can be indexed");
int idx = (int)get_num(idx_val);
struct us_arr *arr = get_arr(arr_val);
if (idx < 0)
idx += da_len(arr->e);
if (idx < 0 || idx >= da_len(arr->e)) {
log_fatal(
1,
"index out of range (%d/%d)",
idx,
da_len(arr->e) - 1
);
}
vm_push(arr->e[idx]);
break;
}
case BC_POP_UPVAL:
close_upvals(vm.stacktop - 1);
vm_pop();
break;
case BC_POP: vm_pop(); break;
case BC_ADD: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
if (b.type != VAL_NUM || a.type != VAL_NUM)
log_fatal(1, "Invalid operands");
vm_push(create_num(get_num(a) + get_num(b)));
break;
}
case BC_SUB: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
if (b.type != VAL_NUM || a.type != VAL_NUM)
log_fatal(1, "Invalid operands");
vm_push(create_num(get_num(a) - get_num(b)));
break;
}
case BC_MULT: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
if (b.type != VAL_NUM || a.type != VAL_NUM)
log_fatal(1, "Invalid operands");
vm_push(create_num(get_num(a) * get_num(b)));
break;
}
case BC_DIV: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
if (b.type != VAL_NUM || a.type != VAL_NUM)
log_fatal(1, "Invalid operands");
vm_push(create_num(get_num(a) / get_num(b)));
break;
}
case BC_MOD: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
if (b.type != VAL_NUM || a.type != VAL_NUM)
log_fatal(1, "Invalid operands");
vm_push(create_num(fmod(get_num(a), get_num(b))));
break;
}
case BC_GT: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
if (b.type != VAL_NUM || a.type != VAL_NUM)
log_fatal(1, "Invalid operands");
vm_push(create_bool(get_num(a) > get_num(b)));
break;
}
case BC_LT: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
if (b.type != VAL_NUM || a.type != VAL_NUM)
log_fatal(1, "Invalid operands");
vm_push(create_bool(get_num(a) < get_num(b)));
break;
}
case BC_GTE: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
if (b.type != VAL_NUM || a.type != VAL_NUM)
log_fatal(1, "Invalid operands");
vm_push(create_bool(get_num(a) >= get_num(b)));
break;
}
case BC_LTE: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
if (b.type != VAL_NUM || a.type != VAL_NUM)
log_fatal(1, "Invalid operands");
vm_push(create_bool(get_num(a) <= get_num(b)));
break;
}
case BC_NEG: {
struct us_val a = vm_pop();
if (a.type != VAL_NUM)
log_fatal(1, "Invalid operand");
vm_push(create_num(-get_num(a)));
break;
}
case BC_NOT: {
bool negated = !as_bool(vm_pop());
vm_push(create_bool(negated));
break;
}
case BC_CONCAT: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
vm_push(wrap_str(concat(a, b)));
break;
}
case BC_EQL: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
vm_push(create_bool(vals_eql(a, b)));
break;
}
case BC_NEQL: {
struct us_val b = vm_pop();
struct us_val a = vm_pop();
vm_push(create_bool(!vals_eql(a, b)));
break;
}
case BC_FALSEY_JMP: {
u16 jmp = read_short(func->proto, &i);
if (as_bool(vm_pop()))
break;
i += jmp;
break;
}
case BC_JMP:
i += read_short(func->proto, &i);
break;
case BC_LOOP:
i -= read_short(func->proto, &i);
break;
case BC_PRINT: {
char *str = val_to_str(vm_pop(), NULL);
olog(str);
mem_free(str);
break;
}
case BC_CALL: {
int argc = read_byte();
struct us_val callee = vm.stacktop[-argc - 1];
if (callee.type != VAL_FUNC)
log_fatal(1, "can only call functions");
struct us_func *func = get_func(callee);
if (argc != func->proto->argc) {
log_fatal(
1,
"wrong number of arguments to '%s()' (%d/%d)",
func->proto->name->chars,
argc,
func->proto->argc
);
}
us_exec(func);
break;
}
case BC_RET: {
struct us_val ret_val = vm_pop();
close_upvals(vm.cf->stackbot - 1);
vm.stacktop = vm.cf->stackbot - 1;
vm.cf--;
vm_push(ret_val);
return;
}
default:
log_fatal(1, "unhandled instruction %d", instruction);
break;
}
}
}
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