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#include <stdarg.h>
#include <stdio.h>
#include "common.h"
#include "compiler.h"
#include "debug.h"
#include "vm.h"
VM vm;
static void resetStack() { vm.stackTop = vm.stack; }
static void runtimeError(const char *format, ...) {
va_list args;
va_start(args, format);
vfprintf(stderr, format, args);
va_end(args);
fputs("\n", stderr);
size_t instruction = vm.ip - vm.chunk->code - 1;
int line = vm.chunk->lines[instruction];
fprintf(stderr, "[line %d] in script\n", line);
resetStack();
}
void initVM() { resetStack(); }
void freeVM() {}
void push(Value value) {
*vm.stackTop = value;
vm.stackTop++;
}
Value pop() {
vm.stackTop--;
return *vm.stackTop;
}
static Value peek(int distance) { return vm.stackTop[-1 - distance]; }
static InterpretResult run() {
#define READ_BYTE() (*vm.ip++)
#define READ_CONSTANT() (vm.chunk->constants.values[READ_BYTE()])
#define BINARY_OP(valueType, op) \
do { \
if (!IS_NUMBER(peek(0)) || !IS_NUMBER(peek(1))) { \
runtimeError("Operands must be numbers."); \
} \
double b = AS_NUMBER(pop()); \
double a = AS_NUMBER(pop()); \
push(valueType(a op b)); \
} while (false)
for (;;) {
#ifdef DEBUG_TRACE_EXECUTION
printf(" ");
for (Value *slot = vm.stack; slot < vm.stackTop; slot++) {
printf("[ ");
printValue(*slot);
printf(" ]");
}
printf("\n");
disassembleInstruction(vm.chunk, (int)(vm.ip - vm.chunk->code));
#endif
uint8_t instruction;
switch (instruction = READ_BYTE()) {
case OP_CONSTANT: {
Value constant = READ_CONSTANT();
push(constant);
break;
}
case OP_ADD:
BINARY_OP(NUMBER_VAL, +);
break;
case OP_SUBTRACT:
BINARY_OP(NUMBER_VAL, -);
break;
case OP_MULTIPLY:
BINARY_OP(NUMBER_VAL, *);
break;
case OP_DIVIDE:
BINARY_OP(NUMBER_VAL, /);
break;
case OP_NEGATE:
if (!IS_NUMBER(peek(0))) {
runtimeError("Operand must be a number.");
return INTERPRET_RUNTIME_ERROR;
}
push(NUMBER_VAL(-AS_NUMBER(pop())));
break;
case OP_RETURN: {
printValue(pop());
printf("\n");
return INTERPRET_OK;
}
}
}
#undef READ_BYTE
#undef READ_CONSTANT
#undef BINARY_OP
}
InterpretResult interpret(const char *source) {
Chunk chunk;
initChunk(&chunk);
if (!compile(source, &chunk)) {
freeChunk(&chunk);
return INTERPRET_COMPILE_ERROR;
}
vm.chunk = &chunk;
vm.ip = vm.chunk->code;
InterpretResult result = run();
freeChunk(&chunk);
return result;
}
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