refactor: split code gen into arch seam

1 files changed, 98 insertions, 3 deletions

diff --git a/src/parser.c b/src/parser.c
index ae7c1b3..5379114 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -586,6 +586,59 @@ static bool parse_while(struct Parser* parser, struct Statement* out)
 	return true;
 }
 
+static bool token_starts_operand(enum TokenType type)
+{
+	return type == TOKEN_IDENTIFIER || type == TOKEN_INTEGER || type == TOKEN_FLOAT
+		|| type == TOKEN_CHAR || type == TOKEN_CARET || type == TOKEN_MINUS;
+}
+
+static bool parse_instruction(struct Parser* parser, struct Token mnemonic, struct Statement* out)
+{
+	struct Expr** operands = NULL;
+	size_t count = 0;
+	size_t capacity = 0;
+
+	// assembly is line-oriented: operands share the mnemonic's line, and a bare
+	// mnemonic like `hlt` is just followed by the next statement
+	if (parser->current.line == mnemonic.line && token_starts_operand(parser->current.type))
+	{
+		do
+		{
+			struct Expr* operand = parse_expression(parser);
+			if (operand == NULL)
+				goto error;
+
+			if (count == capacity)
+			{
+				capacity = capacity < 4 ? 4 : capacity * 2;
+				struct Expr** grown = realloc(operands, capacity * sizeof(struct Expr*));
+				if (grown == NULL)
+				{
+					free_expr(operand);
+					goto error;
+				}
+				operands = grown;
+			}
+			operands[count] = operand;
+			count += 1;
+		}
+		while (match_token(parser, TOKEN_COMMA));
+	}
+
+	out->kind = STATEMENT_INSTRUCTION;
+	out->instruction.mnemonic = mnemonic;
+	out->instruction.operands = operands;
+	out->instruction.operand_count = count;
+	out->instruction.operand_capacity = capacity;
+	return true;
+
+error:
+	for (size_t i = 0; i < count; i += 1)
+		free_expr(operands[i]);
+	free(operands);
+	return false;
+}
+
 static bool parse_statement(struct Parser* parser, struct Statement* out)
 {
 	if (match_token(parser, TOKEN_IF))
@@ -652,6 +705,9 @@ static bool parse_statement(struct Parser* parser, struct Statement* out)
 		return true;
 	}
 
+	if (!deref && !is_assign_op(parser->current.type))
+		return parse_instruction(parser, name, out);
+
 	if (!is_assign_op(parser->current.type))
 	{
 		error_at(parser, parser->current, "expected an assignment operator");
@@ -729,6 +785,18 @@ static bool parse_directive(struct Parser* parser, struct Program* program)
 		return false;
 	struct Token key = parser->previous;
 
+	// bare directive with no value, e.g. [boot]
+	if (match_token(parser, TOKEN_RIGHT_BRACKET))
+	{
+		if (token_text_is(key, "boot"))
+		{
+			program->config.boot = true;
+			return true;
+		}
+		error_at(parser, key, "unknown directive");
+		return false;
+	}
+
 	if (!consume(parser, TOKEN_COLON, "expected ':' after directive name"))
 		return false;
 
@@ -745,12 +813,39 @@ static bool parse_directive(struct Parser* parser, struct Program* program)
 
 	if (token_text_is(key, "bits"))
 	{
-		if (value.type != TOKEN_INTEGER || (!token_text_is(value, "64") && !token_text_is(value, "32")))
+		if (value.type != TOKEN_INTEGER
+			|| (!token_text_is(value, "64") && !token_text_is(value, "32") && !token_text_is(value, "16")))
+		{
+			error_at(parser, value, "bits must be 16, 32 or 64");
+			return false;
+		}
+		program->config.bits = token_text_is(value, "64") ? 64 : token_text_is(value, "32") ? 32 : 16;
+		return true;
+	}
+
+	if (token_text_is(key, "format"))
+	{
+		if (value.type == TOKEN_IDENTIFIER && (token_text_is(value, "elf") || token_text_is(value, "elf64")))
+			program->config.format = OUTPUT_ELF;
+		else if (value.type == TOKEN_IDENTIFIER && (token_text_is(value, "bin") || token_text_is(value, "binary")))
+			program->config.format = OUTPUT_BIN;
+		else
+		{
+			error_at(parser, value, "format must be elf or bin");
+			return false;
+		}
+		return true;
+	}
+
+	if (token_text_is(key, "org"))
+	{
+		if (value.type != TOKEN_INTEGER)
 		{
-			error_at(parser, value, "bits must be 32 or 64");
+			error_at(parser, value, "org must be an integer address");
 			return false;
 		}
-		program->config.bits = token_text_is(value, "64") ? 64 : 32;
+		program->config.has_org = true;
+		program->config.org = value;
 		return true;
 	}