Began working on the value and stack systems

src/vm/value.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2022, Roland Marchand <roland.marchand@protonmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+enum value_type {
+	VALUE_NUMBER = 0,
+	VALUE_BOOL,
+	VALUE_NIL
+};
+
+struct value {
+	union {
+		double number;
+		uint8_t bool;
+	} as;
+	enum value_type type;
+};

src/vm/vm.c

@@ -40,6 +40,7 @@ enum interpret_result interpret(struct source *src) {
 
 	vm.lump = lmp;
 	vm.pc = lmp->array;
+	vm.stack_top = vm.stack;
 
 	enum interpret_result result = run();
 
@@ -72,6 +73,23 @@ static enum interpret_result run()
 			break;
 		}
 	}
-
 #undef READ_BYTE
 }
+
+void vm_push(struct value v)
+{
+	if (vm.stack_top >= vm.stack + VM_STACK_SIZE)
+		return;
+
+	*vm.stack_top = v;
+	vm.stack_top++;
+}
+
+struct value *vm_pop()
+{
+	if (vm.stack_top <= vm.stack)
+		return NULL;
+
+	vm.stack_top--;
+	return vm.stack_top + 1;
+}

src/vm/vm.h

@@ -25,12 +25,17 @@
 
 #include "opcode.h"
 #include "lump.h"
+#include "value.h"
 #include "src/scanner/scanner.h"
 
 #include <stdint.h>
 
+#define VM_STACK_SIZE 256
+
 struct vm {
 	struct lump *lump;
+	struct value stack[VM_STACK_SIZE];
+	struct value *stack_top;
 	uint8_t *pc;
 };
 
@@ -40,6 +45,6 @@ enum interpret_result {
 	INTERPRET_RUNTIME_ERROR
 };
 
-/* void vm_init(); */
-/* void vm_free(); */
 enum interpret_result interpret(struct source *src);
+void vm_push(struct value v);
+struct value *vm_pop();