1 files changed, 198 insertions, 0 deletions
diff --git a/masm/parse.c b/masm/parse.c
new file mode 100644
index 0000000..9876311
--- /dev/null
+++ b/masm/parse.c
@@ -0,0 +1,198 @@
+#include <mlimits.h>
+#include <merror.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "parse.h"
+#include "lex.h"
+
+int next_token(struct parser *parser, struct token *tok)
+{
+	if (parser->peek.type != TOK_EOF) {
+		if (tok != NULL)
+			*tok = parser->peek;
+		parser->peek.type = TOK_EOF;
+		return M_SUCCESS;
+	}
+	struct token token;
+	if (lexer_next(parser->lexer, &token))
+		return M_ERROR;
+	if (tok != NULL)
+		*tok = token;
+	return M_SUCCESS;
+}
+
+
+int peek_token(struct parser *parser, struct token *tok)
+{
+	if (parser->peek.type == TOK_EOF) {
+		if (next_token(parser, &parser->peek))
+			return M_ERROR;
+	}
+	if (tok != NULL)
+		*tok = parser->peek;
+	return M_SUCCESS;
+}
+
+
+int assert_token(struct parser *parser, enum token_type type,
+		 struct token *tok)
+{
+	struct token token;
+	if (next_token(parser, &token))
+		return M_ERROR;
+	if (token.type != type) {
+		ERROR_POS(token, "expected a token of type '%s', got '%s'",
+			token_str(type), token_str(token.type));
+		return M_ERROR;
+	}
+	if (tok != NULL)
+		*tok = token;
+	return M_SUCCESS;
+}
+
+int assert_eol(struct parser *parser)
+{
+	struct token token;
+	if (next_token(parser, &token))
+		return M_ERROR;
+	if (token.type != TOK_NL && token.type != TOK_EOF) {
+		ERROR_POS(token, "expected a new line or end of file");
+		return M_ERROR;
+	}
+	return M_SUCCESS;
+}
+
+static int parse_constant(struct parser *parser, struct const_expr *expr,
+			  struct token ident)
+{
+	struct token number;
+
+	if (assert_token(parser, TOK_EQUAL, NULL))
+		return M_ERROR;
+
+	if (assert_token(parser, TOK_NUMBER, &number))
+		return M_ERROR;
+
+	strcpy(expr->name,ident.text);
+	expr->value = number.number;
+
+	return M_SUCCESS;
+}
+
+static int parser_handle_ident(struct parser *parser, struct expr *expr)
+{
+	struct token ident;
+	struct token peek;
+
+	if (assert_token(parser, TOK_IDENT, &ident))
+		return M_ERROR;
+
+	if (peek_token(parser, &peek))
+		return M_ERROR;
+
+	if (peek.type == TOK_EQUAL) {
+		expr->type = EXPR_CONSTANT;
+		return parse_constant(parser, &expr->constant, ident);
+	} else {
+		expr->type = EXPR_INS;
+		return parser->parse_instruction(parser, &expr->ins, ident);
+	}
+}
+
+
+static int parse_label(struct parser *parser,
+		       struct expr *expr)
+{
+	struct token token;
+	struct symbol symbol;
+	uint32_t index;
+
+	if (assert_token(parser, TOK_LABEL, &token))
+		return M_ERROR;
+	strcpy(expr->text, token.text);
+
+	if (symtbl_find(&parser->sym_tbl, NULL, token.text) == M_SUCCESS) {
+		ERROR_POS(token, "redefined symbol '%s'", token.text);
+		return M_ERROR;
+	}
+
+	index = parser->sec_tbl.current->start +
+		parser->sec_tbl.current->count;
+	symbol = (struct symbol) {
+		.name = "",
+		.position = index,
+		.flag = SYM_LOCAL,
+	};
+	strcpy(symbol.name, token.text);
+
+	if (symtbl_push(&parser->sym_tbl, symbol))
+		return M_ERROR;
+
+	return M_SUCCESS;
+}
+
+
+int parser_next(struct parser *parser, struct expr *expr)
+{
+	struct token token;
+	int res = M_SUCCESS;
+
+again:
+	if (peek_token(parser, &token))
+		return M_ERROR;
+
+	switch (token.type) {
+		case TOK_NL:
+			next_token(parser, NULL);
+			goto again;
+
+		case TOK_EOF:
+			res = M_EOF;
+			break;
+
+		case TOK_LABEL:
+			expr->type = EXPR_LABEL;
+			res = parse_label(parser, expr);
+			break;
+
+		case TOK_DIRECTIVE:
+			expr->type = EXPR_DIRECTIVE;
+			res = parser->parse_directive(parser,
+				 &expr->directive);
+			break;
+
+		case TOK_IDENT:
+			res = parser_handle_ident(parser, expr);
+			break;
+
+		default:
+			ERROR_POS(token, "unexpected token '%s'",
+				token_str(token.type));
+			return M_ERROR;
+
+	}
+
+	return res;
+}
+
+int parser_init(struct lexer *lexer, struct parser *parser)
+{
+        parser->lexer = lexer;
+        parser->peek.type = TOK_EOF;
+	if (symtbl_init(&parser->sym_tbl))
+		return M_ERROR;
+	if (sectbl_init(&parser->sec_tbl))
+		return M_ERROR;
+	if (reftbl_init(&parser->ref_tbl))
+		return M_ERROR;
+	return M_SUCCESS;
+}
+
+
+void parser_free(struct parser *parser)
+{
+	symtbl_free(&parser->sym_tbl);
+	sectbl_free(&parser->sec_tbl);
+	reftbl_free(&parser->ref_tbl);
+}