From aca8d7937e1ebb3655f5b85865f1f0bb602e605b Mon Sep 17 00:00:00 2001
From: Henrik Hautakoski <henrik.hautakoski@gmail.com>
Date: Sun, 9 Dec 2018 19:27:26 +0100
Subject: [PATCH] asm: adding AST

---
 src/as/ast.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/as/ast.h | 81 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 176 insertions(+)
 create mode 100644 src/as/ast.c
 create mode 100644 src/as/ast.h

diff --git a/src/as/ast.c b/src/as/ast.c
new file mode 100644
index 0000000..392517e
--- /dev/null
+++ b/src/as/ast.c
@@ -0,0 +1,95 @@
+
+#include <string.h>
+#include <stdlib.h>
+#include <vector.h>
+#include <stdio.h>
+#include "ast.h"
+
+void ast_init(struct ast* ast) {
+
+	vector_init(&ast->instr, 16 * sizeof(struct ast));
+	vector_init(&ast->labels, 16 * sizeof(char**));
+	ast->symbols = symtab_init();
+}
+
+void ast_free(struct ast* ast) {
+
+	int i;
+
+	// Free all label strings
+	for(int i = 0; i < ast->labels.size; i++) {
+		char *ptr = *((char**) ast->labels.base + i);
+		free(ptr);
+	}
+	vector_destory(&ast->labels);
+	vector_destory(&ast->instr);
+	symtab_free(ast->symbols);
+}
+
+void ast_instr(struct ast* ast, uint8_t opcode) {
+
+	struct ast_instr instr = { 0 };
+
+	instr.opcode = opcode;
+	vector_append(&ast->instr, &instr, sizeof(struct ast_instr));
+}
+
+void ast_instr_operand(struct ast* ast, enum ast_datatype type, void* value) {
+
+	struct ast_instr *instr;
+
+	if (ast->instr.size < 1)
+		return;
+
+	// Fetch latest instruction.
+	instr = ast->instr.base + (ast->instr.size - sizeof(struct ast_instr));
+
+	if (instr->n_operands < 3) {
+		struct ast_instr_operand *n = instr->operands + instr->n_operands;
+
+		n->type = type;
+		if (n->type == DATATYPE_STRING) {
+			n->s = strdup(value);
+			vector_append(&ast->labels, &n->s, sizeof(char**));
+		} else {
+			n->r = ((intptr_t) value) & 0xFF;
+		}
+
+		instr->n_operands++;
+	}
+}
+
+void ast_location(struct ast* ast, const char *label, uint16_t loc) {
+
+	symtab_set(ast->symbols, label, loc);
+}
+
+void ast_print(struct ast* ast) {
+
+	printf("{\n");
+
+	for(int i = 0; i < ast->instr.size; i += sizeof(struct ast_instr)) {
+		struct ast_instr *instr = ast->instr.base + i;
+
+		printf("\topcode: %u", instr->opcode);
+		for(int j = 0; j < instr->n_operands; j++) {
+			struct ast_instr_operand *op = instr->operands + j;
+			printf(", operand%i: ", j);
+			switch(op->type) {
+			case DATATYPE_REGISTER :
+				printf("%u (reg)", op->r);
+				break;
+			case DATATYPE_NUMBER :
+				printf("%i (num)", op->n);
+				break;
+			case DATATYPE_STRING :
+				printf("%s (string)", op->s);
+				break;
+			}
+		}
+		printf("\n");
+	}
+
+	printf("}\n");
+
+}
diff --git a/src/as/ast.h b/src/as/ast.h
new file mode 100644
index 0000000..6c23334
--- /dev/null
+++ b/src/as/ast.h
@@ -0,0 +1,81 @@
+/* ast.h
+ *
+ *   Copyright (C) 2018   Henrik Hautakoski <henrik.hautakoski@gmail.com>
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ *   MA 02110-1301, USA.
+ */
+#ifndef ASM_AST_H
+#define ASM_AST_H
+
+#include <vector.h>
+#include "symtab.h"
+
+// All datatypes in the language.
+enum ast_datatype {
+	DATATYPE_NONE = 0,   // Not an actual type.
+	DATATYPE_REGISTER,   // 4 bit unsigned.
+	DATATYPE_NUMBER,     // 8 bit signed.
+	DATATYPE_STRING
+};
+
+// Struct to represent a single operand to a instruction.
+struct ast_instr_operand {
+	enum ast_datatype type;
+	union {
+		uint8_t     r;
+		int8_t      n;
+		uint16_t    addr;
+		const char *s;
+	};
+};
+
+// Struct to represent a single instruction.
+struct ast_instr {
+	uint8_t opcode;
+	uint8_t n_operands;
+	struct ast_instr_operand operands[3];
+};
+
+// Structure to represent a program.
+struct ast {
+
+	// List of instructions.
+	struct vector instr;
+
+	// List for storing label pointers (so we can free)
+	struct vector labels;
+
+	// Symbol table with label - location mapping.
+	symtab_t *symbols;
+};
+
+void ast_init(struct ast* ast);
+
+void ast_free(struct ast* ast);
+
+// Add an instruction
+void ast_instr(struct ast* ast, uint8_t opcode);
+
+// Add an operand to the latest instruction.
+//void ast_instr_operand(struct ast* ast, const struct ast_instr_operand* op);
+void ast_instr_operand(struct ast* ast, enum ast_datatype type, void* value);
+
+void ast_location(struct ast* ast, const char *label, uint16_t loc);
+
+// For debugging :)
+void ast_print(struct ast* ast);
+
+#endif /* ASM_AST_H */