(*
s1 - Contains the current position in the source text.
s2 - Label counter.

- The compiler expects valid input, otherwise it will generate invalid
assembly or hang. There is no error checking, no semantic analysis, no
type checking.

- Imports with only a module name without package, e.g.
"import dummy", can be parsed, but are ignored.

- No loops. Only labels and goto.

- Only unsigned number literals are supported (in decimal or
hexadecimal format).

- Comments are accepted only at the end of a line.

- Return can be used only as the last statement of a procedure. It
doesn't actually return, but sets a0 to the appropriate value.

- The lvalue of an assignment can only be an identifier.
*)
program

import dummy

const
	SOURCE_BUFFER_SIZE := 81920

var
	source_code: [81920]Byte

(* Ignores the import. *)
proc _compile_import()
var loca0: Word
begin
	_advance(6);
	_skip_spaces();
	loca0 := _read_token();
	_advance(loca0) (* Skip the imported module name. *)
end

proc _build_binary_expression()
var
	loca0, loca4, loca8, loca16, loca20: Word
	loca12: ^Byte
	loca24: Bool
begin
	_build_expression(0);

	loca4 := 0x2c306120 (* _a0, *);
	loca8 := 0x0a316120 (* _a1\n *);

	_skip_spaces();
	loca20 := _read_token();
	loca12 := _current();

	loca16 := 0x26 (* & *);
	loca24 := _token_compare(loca12, loca20, @loca16);
	if loca24 = 0 then
		goto .L_build_binary_expression_and
	end;

	loca16 := 0x726f (* or *);
	loca24 := _token_compare(loca12, loca20, @loca16);
	if loca24 = 0 then
		goto .L_build_binary_expression_or
	end;

	loca16 := 0x3d (* = *);
	loca24 := _token_compare(loca12, loca20, @loca16);
	if loca24 = 0 then
		goto .L_build_binary_expression_equal
	end;

	loca16 := 0x2b (* + *);
	loca24 := _token_compare(loca12, loca20, @loca16);
	if loca24 = 0 then
		goto .L_build_binary_expression_plus
	end;

	loca16 := 0x2d (* - *);
	loca24 := _token_compare(loca12, loca20, @loca16);
	if loca24 = 0 then
		goto .L_build_binary_expression_minus
	end

	loca16 := 0x2a (* * *);
	loca24 := _token_compare(loca12, loca20, @loca16);
	if loca24 = 0 then
		goto .L_build_binary_expression_product
	end;

	goto .Lbuild_binary_expression_end;

	.L_build_binary_expression_equal;
	_advance(1) (* Skip =. *);
	_build_expression(1);

	loca0 := 0x627573(* sub *);
	_write_out(@loca0, 3);
	_write_out(@loca4, 4);
	_write_out(@loca4, 4);
	_write_out(@loca8, 4);

	loca0 := 0x7a716573 (* seqz *);
	_write_out(@loca0, 4);
	_write_out(@loca4, 4);
	_write_out(@loca4, 3);
	_put_char(0x0a) (* \n *);

	goto .Lbuild_binary_expression_end;

	.L_build_binary_expression_and;
	_advance(1) (* Skip &. *);
	_build_expression(1);
	loca0 := 0x646e61 (* and *);
	_write_out(@loca0, 3);
	_write_out(@loca4, 4);
	_write_out(@loca4, 4);
	_write_out(@loca8, 4);

	goto .Lbuild_binary_expression_end;

	.L_build_binary_expression_or;
	_advance(2) (* Skip or. *);
	_build_expression(1);
	loca0 := 0x726f (* or *);
	_write_out(@loca0, 2);
	_write_out(@loca4, 4);
	_write_out(@loca4, 4);
	_write_out(@loca8, 4);

	goto .Lbuild_binary_expression_end;

	.L_build_binary_expression_plus;
	_advance(1) (* Skip +. *);
	_build_expression(1);
	loca0 := 0x646461 (* add *);
	_write_out(@loca0, 3);
	_write_out(@loca4, 4);
	_write_out(@loca4, 4);
	_write_out(@loca8, 4);

	goto .Lbuild_binary_expression_end;

	.L_build_binary_expression_minus;
	_advance(1) (* Skip -. *);
	_build_expression(1);
	loca0 := 0x627573 (* sub *);
	_write_out(@loca0, 3);
	_write_out(@loca4, 4);
	_write_out(@loca4, 4);
	_write_out(@loca8, 4);

	goto .Lbuild_binary_expression_end;

	.L_build_binary_expression_product;
	_advance(1) (* Skip *. *);
	_build_expression(1);
	loca0 := 0x6c756d (* mul *);
	_write_out(@loca0, 3);
	_write_out(@loca4, 4);
	_write_out(@loca4, 4);
	_write_out(@loca8, 4);

	goto .Lbuild_binary_expression_end;

	.Lbuild_binary_expression_end
end

(*
Parameters:
a0 - Identifier length.
a1 - Register number as character.
*)
proc _compile_identifier_expression(loca84: Word, loca80: Byte)
begin
	loca24 := _current();
	loca0 := 0x61636f6c (* loca *);
	loca0 := _memcmp(@loca0, loca24, 4);

	if loca0 = 0 then
		loca8 := 0x6120776c (* lw a *);
		_write_out(@loca8, 4);
		loca8 := 0x00202c00 or loca80 (* \0,_ *);
		_write_out(@loca8, 3);

		loca4 := loca24 + 4;
		loca0 := loca84 - 4;
		_write_out(loca4, loca0) (* Skip the "loca" variable prefix. *);

		loca8 := 0x29707328 (* (sp) *);
		_write_out(@loca8, 4);
		_put_char(0x0a) (* \n *);

		goto .Lcompile_identifier_expression_end
	end;
	loca0 := _front(loca24);
	loca8 := loca84 = 2;
	loca12 := loca0 = 0x73;
	if loca8 & loca12 then
		loca8 := 0x6120766d (* mv a *);
		_write_out(@loca8, 4);
		loca8 := 0x00202c00 or loca80 (* \0,_ *);
		_write_out(@loca8, 3);
		_write_out(loca24, loca84);
		_put_char(0x0a) (* \n *);

		goto .Lcompile_identifier_expression_end
	end

	(* Global identifier. *);
	loca8 := 0x6120616c (* la a *);
	_write_out(@loca8, 4);
	loca8 := 0x00202c00 or loca80;
	_write_out(@loca8, 3);

	_write_out(loca24, loca84);
	_put_char(0x0a);

	if _is_upper(loca0) then
		loca8 := 0x6120776c (* lw a *);
		_write_out(@loca8, 4);
		loca8 := 0x28202c00 or loca28 (* \0, ( *);
		_write_out(@loca8, 4);
		_put_char(0x61) (* a *);
		_put_char(loca28);
		_put_char(0x29) (* ) *);
		_put_char(0x0a) (* \n *);

		goto .Lcompile_identifier_expression_end
	end;

	.Lcompile_identifier_expression_end
end

(*
Evalutes an expression and saves the result in a0.

a0 - X in aX, the register number to save the result.
*)
proc _build_expression()
var
	loca0, loca20, loca28, loca8: Word
	loca24, loca4: ^Byte
begin
	(* Make the register number to a character and save it. *)
	loca28 := loca84 + 0x30 (* 0 *);

	_skip_spaces();
	loca20 := _read_token();
	loca24 := _current();
	loca0 := _front(loca24);

	(* - *)
	if loca0 = 0x2d then
		goto .Lbuild_expression_negate
	end;

	(* @ *)
	if loca0 = 0x40 then
		goto .Lbuild_expression_address
	end;

	if _is_digit(loca0) then
		goto .Lbuild_expression_literal
	end;

	(* _ *)
	if loca0 = 0x5f then
		goto .Lbuild_expression_call
	end;

	_compile_identifier_expression(loca20, loca28);
	goto .Lbuild_expression_advance;

	.Lbuild_expression_negate;
	_advance(1) (* Skip the -. *);
	_build_expression(0);

	loca8 := 0x2067656e (* neg_ *);
	_write_out(@loca8, 4);
	loca8 := 0x202c3061 (* a0,_ *);
	_write_out(@loca8, 4);
	loca8 := 0x0a3061 (* a0,_ *);
	_write_out(@loca8, 3);

	goto .Lbuild_expression_advance;

	.Lbuild_expression_address;
	loca8 := 0x69646461 (* addi *);
	_write_out(@loca8, 4);
	loca8 := 0x6120 (* _a *);
	_write_out(@loca8, 2);
	_put_char(loca28);
	loca8 := 0x7073202c (* , sp *);
	_write_out(@loca8, 4);
	loca8 := 0x202c (* ,_ *);
	_write_out(@loca8, 2);

	_advance(1) (* Skip @. *);
	_skip_spaces();
	loca24 := _current();
	loca20 := _read_token();

	(* Skip the "loca" variable prefix. *)
	loca4 := loca24 + 4;
	loca0 := loca20 - 4;
	_write_out(loca4, loca0);

	_put_char(0xa);

	goto .Lbuild_expression_advance;

	.Lbuild_expression_call;
	_advance(loca20);
	_advance(1);
	_compile_call(loca24, loca20);

	goto .Lbuild_expression_end;

	.Lbuild_expression_literal;
	loca8 := 0x6120696c (* li a *);
	_write_out(@loca8, 4);
	loca8 := 0x00202c00 or loca28 (* \0,_ *);
	_write_out(@loca8, 3);

	_write_out(loca24, loca20);
	_put_char(0x0a) (* \n *);

	goto .Lbuild_expression_advance;

	.Lbuild_expression_advance;
	_advance(loca20);

	.Lbuild_expression_end
end

(*
Compiles an lvalue.

Parameters:
a0 - Pointer to the identifier.
a1 - Identifier length.
*)
proc _compile_designator_expression(loca84: ^Byte, loca80: Word)
var
	loca0: Word
begin
	loca0 := 0x61636f6c (* loca *);
	loca4 := _memcmp(@loca0, loca84, 4);

	if loca4 = 0 then
		loca0 := 0x61207773 (* sw a *);
		_write_out(@loca0, 4);
		loca0 := 0x202c30 (* 0,_ *);
		_write_out(@loca0, 3);

		loca84 := loca84 + 4;
		loca80 := loca80 - 4;
		_write_out(loca84, loca80);

		loca0 := 0x29707328 (* (sp) *);
		_write_out(@loca0, 4);
		_put_char(0x0a) (* \n *);

		goto .Lcompile_designator_expression_end
	end;
	loca8 := _front(loca84);
	loca12 := loca8 = 0x73 (* s *);
	loca16 := loca80 = 2;
	if loca12 & loca16 then
		loca0 := 0x20766d (* mv_ *);
		_write_out(@loca0, 3);
		_write_out(loca84, loca80);
		loca0 := 0x3061202c (* , a0 *);
		_write_out(@loca0, 4);
		_put_char(0x0a) (* \n *);

		goto .Lcompile_designator_expression_end
	end;

	.Lcompile_designator_expression_end
end

(*
Compiles a statement beginning with an identifier.

Left values should be variables named "loca n", where n is the offset
of the variable on the stack, like loca8 or loca4.
*)
proc _compile_identifier()
var
	loca0, loca16, loca8: Word
	loca20, loca12: ^Byte
	loca4: Bool
begin
	(* Save the pointer to the identifier and its length on the stack. *)
	loca20 := _current();
	loca16 := _read_token();

	_advance(loca16);
	_skip_spaces();

	(* Save the pointer and the length of the token following the identifier. *)
	loca12 := _current();
	loca8 := _read_token();

	_advance(loca8) (* Skip that token. *);
	_skip_spaces();

	loca0 := 0x3d3a (* := *);
	loca4 := _token_compare(loca12, loca8, @loca0);
	if loca4 = 0 then
		_build_binary_expression();
		_compile_designator_expression(loca20, loca16);

		goto .Lcompile_identifier_end
	end;
	if _front(loca12) = 0x28 then
		_compile_call(loca20, loca16);

		goto .Lcompile_identifier_end
	end;

	.Lcompile_identifier_end
end

(*
Compiles a procedure call. Expects s1 to point to the first argument.
a0 - Pointer to the procedure name.
a1 - Length of the procedure name.

Returns the procedure result in a0.
*)
proc _compile_call(loca84: ^Byte, loca80: Word)
var
	loca0, loca4, loca12: Word
	loca8: ^Byte
begin
	loca12 := 0 (* Argument count for a procedure call. *);

	.Lcompile_call_paren;
	_skip_spaces();
	loca8 := _current();
	if _front(loca8) = 0x29 then
		goto .Lcompile_call_complete
	end;

	.Lcompile_call_argument;
	_build_expression(0);

	loca0 := 0x61207773 (* sw a *);
	_write_out(@loca0, 4);
	loca0 := 0x202c30 (* 0,_ *);
	_write_out(@loca0, 3);

	(*
	Only 6 arguments are supported with a0-a5.
	Save all arguments on the stack so they aren't overriden afterwards.
	*)
	loca0 := -4 * loca12;
	loca0 := loca0 + 60;
	_printi(loca0);

	loca0 := 0x29707328 (* (sp) *);
	_write_out(@loca0, 4);
	_put_char(0x0a) (* \n *);

	_skip_spaces();
	loca8 := _current();
	loca0 := _front(loca8) = 0x2c;
	if loca0 = 0 then
		goto .Lcompile_call_paren
	end

	loca12 := loca12 + 1 (* Argument count for a procedure call. *);

	_advance(1) (* Skip the comma between the arguments. *);
	goto .Lcompile_call_argument;

	.Lcompile_call_complete;
	loca12 := 0;

	.Lcompile_call_restore;
	(*
	Just go through all a0-a5 registers and read them from stack.
	If this stack value contains garbage, the procedure just shouldn't use it.
	*)
	loca0 := 0x6120776c (* lw a *);
	(* lw a0, 60(sp) *)
	_write_out(@loca0, 4);
	loca4 := 0x36202c30 (* 0, 6 *);
	_write_out(@loca4, 4);
	loca4 := 0x70732830 (* 0(sp *);
	_write_out(@loca4, 4);
	loca4 := 0x0a29 (* )\n *);
	_write_out(@loca4, 2);

	(* lw a1, 56(sp) *)
	_write_out(@loca0, 4);
	loca4 := 0x35202c31 (* 1, 5 *);
	_write_out(@loca4, 4);
	loca4 := 0x70732836 (* 6(sp *);
	_write_out(@loca4, 4);
	loca4 := 0x0a29 (* )\n *);
	_write_out(@loca4, 2);

	(* lw a2, 52(sp) *)
	_write_out(@loca0, 4);
	loca4 := 0x35202c32 (* 2, 5 *);
	_write_out(@loca4, 4);
	loca4 := 0x70732832 (* 2(sp *);
	_write_out(@loca4, 4);
	loca4 := 0x0a29 (* )\n *);
	_write_out(@loca4, 2);

	(* lw a3, 48(sp) *)
	_write_out(@loca0, 4);
	loca4 := 0x34202c33 (* 3, 4 *);
	_write_out(@loca4, 4);
	loca4 := 0x70732838 (* 8(sp *);
	_write_out(@loca4, 4);
	loca4 := 0x0a29 (* )\n *);
	_write_out(@loca4, 2);

	(* lw a4, 44(sp) *)
	_write_out(@loca0, 4);
	loca4 := 0x34202c34 (* 4, 4 *);
	_write_out(@loca4, 4);
	loca4 := 0x70732834 (* 4(sp *);
	_write_out(@loca4, 4);
	loca4 := 0x0a29 (* )\n *);
	_write_out(@loca4, 2);

	(* lw a5, 40(sp) *)
	_write_out(@loca0, 4);
	loca4 := 0x34202c35 (* 5, 4 *);
	_write_out(@loca4, 4);
	loca4 := 0x70732830 (* 0(sp *);
	_write_out(@loca4, 4);
	loca4 := 0x0a29 (* )\n *);
	_write_out(@loca4, 2);

	loca0 := 0x6c6c6163 (* call *);
	_write_out(@loca0, 4);
	_put_char(0x20) (* _ *);

	_write_out(loca84, loca80);
	_put_char(0x0a) (* \n *);

	_skip_spaces();
	_advance(1) (* Skip the close paren. *)
end

(*
Reads a token and returns its length in a0.
_read_token doesn't change s1, it finds the length of the token s1 is pointing to.
*)
proc _read_token()
var
	loca0, loca4: Word
	loca8: ^Byte
begin
	loca8 := _current();
	loca0 := _front(loca8) (* t0 = Current character. *);
	loca4 := 0;

	(* . *)
	if loca0 = 0x2e then
		goto .Ltoken_character_single
	end;

	(* , *)
	if loca0 = 0x2c then
		goto .Ltoken_character_single
	end;

	(* : *)
	if loca0 = 0x3a then
		goto .Ltoken_character_colon
	end;

	(* ; *)
	if loca0 = 0x3b then
		goto .Ltoken_character_single
	end;

	(* ( *)
	if loca0 = 0x28 then
		goto .Ltoken_character_single
	end;

	(* ) *)
	if loca0 = 0x29 then
		goto .Ltoken_character_single
	end;

	(* [ *)
	if loca0 = 0x5b then
		goto .Ltoken_character_single
	end;

	(* ] *)
	if loca0 = 0x5d then
		goto .Ltoken_character_single
	end;

	(* ^ *)
	if loca0 = 0x5e then
		goto .Ltoken_character_single
	end;

	(* & *)
	if loca0 = 0x26 then
		goto .Ltoken_character_single
	end;

	(* = *)
	if loca0 = 0x3d then
		goto .Ltoken_character_single
	end;

	(* + *)
	if loca0 = 0x2b then
		goto .Ltoken_character_single
	end;

	(* - *)
	if loca0 = 0x2d then
		goto .Ltoken_character_single
	end;

	(* * *)
	if loca0 = 0x2a then
		goto .Ltoken_character_single
	end;

	(* @ *)
	if loca0 = 0x40 then
		goto .Ltoken_character_single
	end;

	(* Expect an identifier or a number. *)
	.Ltoken_character_loop_do;
	loca0 := loca8 + loca4;
	loca0 := _front(loca0);

	if _is_alnum(loca0) then
		loca4 := loca4 + 1;
		goto .Ltoken_character_loop_do;

		.Ltoken_character_single;
		loca4 := loca4 + 1;
		goto .Ltoken_character_end;

		.Ltoken_character_colon;
		loca0 := loca8 + 1;
		loca0 := _front(loca0) (* t0 = The character after the colon. *);
		loca4 := loca4 + 1;

		(* = *)
		if loca0 = 0x3d then
			goto  .Ltoken_character_single
		end
	end;
	.Ltoken_character_end;
	return loca4
end

(* Skips the spaces till the next non space character. *)
proc _skip_spaces()
var
	loca0: Byte
	loca4: ^Byte
begin
	.Lspace_loop_do;
	loca4 := _current();
	loca0 := _front(loca4) (* t0 = Current character. *);

	(* _ *)
	if loca0 = 0x20 then
		goto .Lspace_loop_repeat
	end;
	(* \t *)
	if loca0 = 0x09 then
		goto .Lspace_loop_repeat
	end;
	(* \n *)
	if loca0 = 0x0a then
		goto .Lspace_loop_repeat
	end;
	(* \r *)
	if loca0 = 0x0d then
		goto .Lspace_loop_repeat
	end;

	goto .Lspace_loop_end;
	.Lspace_loop_repeat;
	_advance(1);
	goto .Lspace_loop_do;

	.Lspace_loop_end
end

(*
Parameters:
	a0 - Line length.
*)
proc _skip_comment(loca84: Word)
var
	loca0: ^Byte
	loca4: Word
	loca8: Int
begin
	loca0 := _current();

	(* Check whether this is a comment. *)
	loca4 := 0x2a28 (* ( and * *);
	loca8 := _memcmp(loca0, @loca4, 2);
	if loca8 = 0 then
		goto .Lskip_comment_continue
	end;
	goto .Lskip_comment_end;

	.Lskip_comment_continue;
	_advance(2) (* Skip (*. *);

	loca4 := 0x292a (* ( and * *);

	.Lskip_comment_loop;
	loca0 := _current();
	loca8 := _memcmp(loca0, @loca4, 2);
	if loca8 = 0 then
		goto .Lskip_comment_close
	end;

	_advance(1);

	goto .Lskip_comment_loop;

	.Lskip_comment_close;
	_advance(2) (* Skip "*" and ")". *);

	.Lskip_comment_end
end

(*
Parameters:
	a0 - Line length.
*)
proc _compile_assembly(loca84: Word)
var loca0: ^Byte
begin
	(* Write the source to the standard output. *)
	loca0 := _current();

	_write_out(loca0, loca84);
	_advance(loca84);

	_put_char(0xa) (* \n *);

	_advance(1) (* Skip the new line. *)
end

proc _compile_program()
var loca0: Word
begin
	(* .global _start *)
	loca0 := 0x6f6c672e (* .glo *);
	_write_out(@loca0, 4);
	loca0 := 0x206c6162 (* bal_ *);
	_write_out(@loca0, 4);
	loca0 := 0x6174735f (* _sta *);
	_write_out(@loca0, 4);
	loca0 := 0x0a7472 (* rt\n *);
	_write_out(@loca0, 3);

	_advance(8) (* program\n. *)
end

proc _compile_constant_section()
var
	loca0: Word
	loca4: ^Byte
begin
	(* .section .rodata *)
	loca0 := 0x6365732e (* .sec *);
	_write_out(@loca0, 4);
	loca0 := 0x6e6f6974 (* tion *);
	_write_out(@loca0, 4);
	loca0 := 0x6f722e20 (* _.ro *);
	_write_out(@loca0, 4);
	loca0 := 0x61746164 (* data *);
	_write_out(@loca0, 4);
	loca0 := 0x0a (* \n *);
	_write_out(@loca0, 1);

	_advance(6) (* const\n. *);

	.Lcompile_constant_section_item;
	_skip_spaces();
	loca4 := _current();
	loca0 := _front(loca4);
	if _is_upper(loca0) then
		_compile_constant();
		goto .Lcompile_constant_section_item
	end;

	.Lcompile_constant_section_end
end

proc _compile_constant()
var
	loca0, loca4: Word
	loca8: ^Byte
begin
	loca4 := _read_token();
	loca8 := _current() (* Save the identifier pointer before advancing it. *);

	_write_out(loca8, loca4);
	_advance(loca4);

	_skip_spaces();
	_advance(2) (* Skip the assignment sign. *);

	(* : .long *)
	loca0 := 0x6c2e203a (* : .l *);
	_write_out(@loca0, 4);
	loca0 := 0x20676e6f (* ong_ *);
	_write_out(@loca0, 4);

	_skip_spaces();
	loca4 := _read_token();
	loca8 := _current() (* Save the literal pointer before advancing it. *);

	_write_out(loca8, loca4);
	_advance(loca4);

	_put_char(0x0a) (* \n *)
end

proc _compile_variable_section()
var
	loca0: Word
	loca4: ^Byte
begin
	(* .section .bss *)
	loca0 := 0x6365732e (* .sec *);
	_write_out(@loca0, 4);
	loca0 := 0x6e6f6974 (* tion *);
	_write_out(@loca0, 4);
	loca0 := 0x73622e20 (* _.bs *);
	_write_out(@loca0, 4);
	loca0 := 0x0a73 (* s\n *);
	_write_out(@loca0, 2);

	_advance(4) (* var\n. *);

	.Lcompile_variable_section_item;
	_skip_spaces();
	loca4 := _current();
	loca0 := _front(loca4);

	if _is_lower(loca0) = 0 then
		goto .Lcompile_variable_section_end
	end;
	_compile_variable();
	goto .Lcompile_variable_section_item;

	.Lcompile_variable_section_end
end

proc _compile_variable()
var
	loca28, loca16: ^Byte
	loca0, loca24, loca20: Word
begin
	(* Save the identifier on the stack since it should emitted multiple times. *)
	loca24 := _read_token();
	loca28 := _current();

	_advance(loca24);

	_skip_spaces();
	_advance(1) (* Skip the colon in front of the type. *);

	_skip_spaces();
	_advance(1) (* Skip the opening bracket. *);

	(* Save the array size on the stack since it has to be emitted multiple times. *)
	loca16 := _read_token();
	loca20 := _current();
	_advance(loca16);

	_skip_spaces();
	_advance(1) (* Skip the closing bracket. *);

	_skip_spaces();
	loca0 := _read_token();
	_advance(loca0) (* Skip the type. *);

	(* .type identifier, @object *)
	loca0 := 0x7079742e (* .typ *);
	_write_out(@loca0, 4);
	loca0 := 0x2065 (* e_ *);
	_write_out(@loca0, 2);

	_write_out(loca28, loca24);

	loca0 := 0x6f40202c (* , @o *);
	_write_out(@loca0, 4);
	loca0 := 0x63656a62 (* bjec *);
	_write_out(@loca0, 4);
	loca0 := 0x0a74 (* t\n *);
	_write_out(@loca0, 2);

	(* .size identifier, size *);
	loca0 := 0x7a69732e (* .siz *);
	_write_out(@loca0, 4);
	loca0 := 0x2065 (* e_ *);
	_write_out(@loca0, 2);

	_write_out(loca28, loca24);

	loca0 := 0x202c (* ,_ *);
	_write_out(@loca0, 2);

	_write_out(loca20, loca16);
	_put_char(0x0a) (* \n *);

	(* identifier: .zero size *)
	_write_out(loca28, loca24);

	loca0 := 0x7a2e203a (* : .z *);
	_write_out(@loca0, 4);
	loca0 := 0x206f7265 (* ero_ *);
	_write_out(@loca0, 4);

	_write_out(loca20, loca16);

	_put_char(0x0a) (* \n *)
end

proc _compile_procedure()
var
	loca0, loca4, loca8, loca12, loca16: Word
	loca20, loca24: ^Byte
begin
	_advance(5) (* Skip proc_ *);
	loca16 := _read_token();
	loca20 := _current();
	_advance(loca16);

	(* .type identifier, @function *);
	loca0 := 0x7079742e (* .typ *);
	_write_out(@loca0, 4);
	loca0 := 0x2065 (* e_ *);
	_write_out(@loca0, 2);

	_write_out(loca20, loca16);

	loca0 := 0x6640202c (* , @f *);
	_write_out(@loca0, 4);
	loca0 := 0x74636e75 (* unct *);
	_write_out(@loca0, 4);
	loca0 := 0x0a6e6f69 (* ion\n *);
	_write_out(@loca0, 4);

	_write_out(loca20, loca16);

	loca0 := 0x0a3a (* :\n *);
	_write_out(@loca0, 2);

	_skip_spaces();
	_advance(1) (* Skip opening argument paren. *);
	_skip_spaces();
	_advance(1) (* Skip closing argument paren. *);

	loca12 := 0x6e (* n *);
	loca8 := 0x69676562 (* begi *);

	(*
	Skip all declarations until we find the "begin" keyword, denoting the
	beginning of the procedure body.
	*)
	.Lcompile_procedure_begin;
	_skip_spaces();
	loca0 := _read_token();

	loca24 := _current();
	_advance(loca0);
	loca0 := _token_compare(loca24, loca0, @loca8);

	if loca0 = 1 then
		goto .Lcompile_procedure_begin
	end;

	(* Generate the procedure prologue with a predefined stack size. *)
	loca0 := 0x69646461 (* addi *);
	_write_out(@loca0, 4);

	loca0 := 0x2c707320 (* _sp, *);
	_write_out(@loca0, 4);
	_write_out(@loca0, 4);

	loca0 := 0x0a36392d (* -96\n *);
	_write_out(@loca0, 4);

	loca0 := 0x72207773 (* sw r *);
	_write_out(@loca0, 4);
	loca0 := 0x39202c61 (* a, 9 *);
	_write_out(@loca0, 4);
	loca0 := 0x70732832 (* 2(sp *);
	_write_out(@loca0, 4);
	loca0 := 0x0a29 (* )\n *);
	_write_out(@loca0, 2);

	loca0 := 0x73207773 (* sw s *);
	_write_out(@loca0, 4);
	loca0 := 0x38202c30 (* 0, 8 *);
	_write_out(@loca0, 4);
	loca0 := 0x70732838 (* 8(sp *);
	_write_out(@loca0, 4);
	loca0 := 0x0a29 (* )\n *);
	_write_out(@loca0, 2);

	loca0 := 0x69646461 (* addi *);
	_write_out(@loca0, 4);
	loca0 := 0x2c307320 (* _s0, *);
	_write_out(@loca0, 4);
	loca0 := 0x2c707320 (* _sp, *);
	_write_out(@loca0, 4);
	loca0 := 0x0a363920 (* _96\n *);
	_write_out(@loca0, 4);

	(* Save passed arguments on the stack. *)
	loca0 := 0x61207773 (* sw a *);
	_write_out(@loca0, 4);
	loca4 := 0x38202c30 (* 0, 8 *);
	_write_out(@loca4, 4);
	loca8 := 0x70732834 (* 4(sp *);
	_write_out(@loca8, 4);
	loca12 := 0x0a29 (* )\n *);
	_write_out(@loca12, 2);

	_write_out(@loca0, 4);
	loca4 := 0x38202c31 (* 1, 8 *);
	_write_out(@loca4, 4);
	loca8 := 0x70732830 (* 0(sp *);
	_write_out(@loca8, 4);
	_write_out(@loca12, 2);

	_write_out(@loca0, 4);
	loca4 := 0x37202c32 (* 2, 7 *);
	_write_out(@loca4, 4);
	loca8 := 0x70732836 (* 6(sp *);
	_write_out(@loca8, 4);
	_write_out(@loca12, 2);

	_write_out(@loca0, 4);
	loca4 := 0x37202c33 (* 3, 7 *);
	_write_out(@loca4, 4);
	loca8 := 0x70732832 (* 2(sp *);
	_write_out(@loca8, 4);
	_write_out(@loca12, 2);

	_write_out(@loca0, 4);
	loca4 := 0x36202c34 (* 4, 6 *);
	_write_out(@loca4, 4);
	loca8 := 0x70732838 (* 8(sp *);
	_write_out(@loca8, 4);
	_write_out(@loca12, 2);

	_write_out(@loca0, 4);
	loca4 := 0x36202c35 (* 5, 6 *);
	_write_out(@loca4, 4);
	loca8 := 0x70732838 (* 4(sp *);
	_write_out(@loca8, 4);
	_write_out(@loca12, 2);

	(* Generate the body of the procedure. *)
	.Lcompile_procedure_body;
	_skip_spaces();
	loca12 := _read_line();
	loca8 := 0x0a646e65 (* end\n *);
	loca24 := _current();
	loca8 := _memcmp(loca24, @loca8, 4);

	if loca8 = 0 then
		goto .Lcompile_procedure_end
	end;

	_compile_line(loca12);
	goto .Lcompile_procedure_body;

	.Lcompile_procedure_end;
	_advance(4) (* Skip end\n. *);

	(* Generate the procedure epilogue with a predefined stack size. *)
	loca0 := 0x7220776c (* lw r *);
	_write_out(@loca0, 4);
	loca0 := 0x39202c61 (* a, 9 *);
	_write_out(@loca0, 4);
	loca0 := 0x70732832 (* 2(sp *);
	_write_out(@loca0, 4);
	loca0 := 0x0a29 (* )\n *);
	_write_out(@loca0, 2);

	loca0 := 0x7320776c (* lw s *);
	_write_out(@loca0, 4);
	loca0 := 0x38202c30 (* 0, 8 *);
	_write_out(@loca0, 4);
	loca0 := 0x70732838 (* 8(sp *);
	_write_out(@loca0, 4);
	loca0 := 0x0a29 (* )\n *);
	_write_out(@loca0, 2);

	loca0 := 0x69646461 (* addi *);
	_write_out(@loca0, 4);

	loca0 := 0x2c707320 (* _sp, *);
	_write_out(@loca0, 4);
	_write_out(@loca0, 4);

	loca0 := 0x0a3639 (* 96\n *);
	_write_out(@loca0, 4);

	loca0 := 0x0a746572 (* ret\n *);
	_write_out(@loca0, 4)
end

(*
Compares two string, which of one has a length, the other one is null-terminated.

	a0 - The address of the token string.
	a1 - The length of the string in a0.
	a2 - The address of the null-terminated string.

If the strings match sets a0 to 0, otherwise sets it to 1.
*)
proc _token_compare(loca84: ^Byte, loca80: Word, loca76: ^Byte)
var
	loca0: Bool
	loca4, loca12: Byte
	loca8: Word
begin
	.Ltoken_compare_loop;
	loca4 := _front(loca76);

	(*
	Will only be 0 if the current character in the null terminated string is \0 and the remaining length of the
	another string is 0.
	*)
	loca8 := loca4 or loca80;
	if loca8 = 0 then
		goto .Ltoken_compare_equal
	end;
	if loca80 = 0 then
		goto .Ltoken_compare_not_equal
	end;
	if loca4 = 0 then
		goto .Ltoken_compare_not_equal
	end;
	loca12 := _front(loca84);
	if loca4 = loca12 then
		goto .Ltoken_compare_continue
	end;
	goto .Ltoken_compare_not_equal;

	.Ltoken_compare_continue;

	loca84 := loca84 + 1;
	loca80 := loca80 - 1;
	loca76 := loca76 + 1;
	goto .Ltoken_compare_loop;

	.Ltoken_compare_not_equal;
	loca0 := 1;
	goto .Ltoken_compare_end;

	.Ltoken_compare_equal;
	loca0 := 0;

	.Ltoken_compare_end;
	return loca0
end

proc _compile_goto()
var
	loca0: Word
	loca8: ^Byte
begin
	_advance(4) (* Skip the goto keyword. *);

	loca0 := 0x206a (* j_ *);
	_write_out(@loca0, 2);

	_skip_spaces();
	loca8 := _current() (* We should be on dot the label is beginning with. *);
	_advance(1);

	loca0 := _read_token();
	_advance(loca0);
	loca0 := loca0 + 1 (* Label length and the dot. *);
	_write_out(loca8, loca0);

	_advance(1) (* Skip the new line. *);
	_put_char(0x0a) (* \n *)
end

(* a0 - Line length. *)
proc _compile_label(loca84: Word)
var
	loca0: Word
begin
	(* Write the whole line as is. *)
	loca0 := _current();

	loca0 := loca0 + loca84;
	loca0 := loca0 - 1 (* Last character on the line. *);
	loca4 := loca84;

	loca0 := _front(loca0);
	if loca0 = 0x3b then
		loca4 := loca4 - 1
	end;
	_write_out(s1, loca4);

	_put_char(0x3a) (* : *);
	_put_char(0x0a) (* \n *);

	_advance(loca84)
end

proc _compile_return()
begin
	_advance(6) (* Skip return. *);
	_skip_spaces();
	_build_binary_expression();
end

proc _compile_if()
var
	loca8, loca12, loca16, loca20: Word
	loca4: ^Byte
begin
	_advance(2) (* Skip the if. *);
	_skip_spaces();

	_build_binary_expression();

	_skip_spaces();
	_advance(4) (* Skip the then. *);

	loca20 := 0x00646e65 (* if end marker and newline. *);
	loca16 := 0x66694c2e (* Label prefix ".Lif". *);

	loca12 := 0x7a716562 (* beqz *);
	_write_out(@loca12, 4);
	loca12 := 0x2c306120 (* _a0, *);
	_write_out(@loca12, 4);
	_put_char(0x20) (* _ *);

	(* Write the label *);
	_write_out(@loca16, 4);
	_printi(s2);

	_put_char(0x0a) (* \n *);

	.Lcompile_if_loop;
	_skip_spaces();
	loca12 := _read_token();

	loca4 := _current();
	loca8 := _token_compare(loca4, loca12, @loca20);

	if loca8 then
		loca12 := _read_line();
		_compile_line(loca12, 1);

		goto .Lcompile_if_loop
	end;

	(* Write the label *)
	_write_out(@loca16, 4);
	_printi(s2);

	loca12 := 0x0a3a0a3a (* :\n:\n *);
	_write_out(@loca12, 2);

	(* Increment the label counter. *);
	s2 := s2 + 1;
	_advance(4) (* Skip the end with newline. *)
end

(*
Parameters:
	a0 - Line length.
	a1 - Whether the section header was already emitted. If not it should be
	emitted before any code is written.

Returns 1 in a0 if the parsed line contained a text section element such a
procedure or the program entry point. Otherwise sets a0 to 0.
*)
proc _compile_line(loca84: Word, loca80: Bool)
var
	loca0: Char
	loca4: Int
	loca8: Bool
	loca12: Word
	loca16: ^Byte
begin
	if loca84 = 0 then
		goto .Lcompile_line_empty (* Skip an empty line. *)
	end;

	loca16 := _current();
	loca0 := _front(loca16);
	(* ( *)
	if loca0 = 0x28 then
		goto .Lcompile_line_comment
	end;
	loca16 := _current();

	loca12 := 0x676f7270 (* prog *);
	loca4 := _memcmp(loca16, @loca12, 4);
	if loca4 = 0 then
		goto .Lcompile_line_program
	end;

	loca12 := 0x736e6f63 (* cons *);
	loca4 := _memcmp(loca16, @loca12, 4);
	if loca4 = 0 then
		goto .Lcompile_line_const
	end;

	loca12 := 0x0a726176 (* var\n *);
	loca4 := _memcmp(loca16, @loca12, 4);
	if loca4 = 0 then
		goto .Lcompile_line_var
	end;

	loca12 := 0x636f7270 (* proc *);
	loca4 := _memcmp(loca16, @loca12, 4);
	if loca4 = 0 then
		goto .Lcompile_line_procedure
	end;

	loca12 := 0x69676562 (* begi *);
	loca4 := _memcmp(loca16, @loca12, 4);
	if loca4 = 0 then
		goto .Lcompile_line_begin
	end;

	loca12 := 0x2e646e65 (* end. *);
	loca4 := _memcmp(loca16, @loca12, 4);
	if loca4 = 0 then
		goto .Lcompile_line_exit
	end;

	loca12 := 0x61636f6c (* loca *);
	loca4 := _memcmp(loca16, @loca12, 4);
	if loca4 = 0 then
		goto .Lcompile_line_identifier
	end;
	loca4 := _front(loca16);
	if loca4 = 0x73 then
		goto .Lcompile_line_identifier
	end;

	loca12 := 0x6f706d69 (* impo *);
	loca4 := _memcmp(loca16, @loca12, 4);
	if loca4 = 0 then
		goto .Lcompile_line_import
	end;

	loca12 := 0x6f746f67 (* goto *);
	loca4 := _memcmp(loca16, @loca12, 4);
	if loca4 = 0 then
		goto .Lcompile_line_goto
	end;

	loca12 := 0x75746572 (* retu *);
	loca4 := _memcmp(loca16, @loca12, 4);
	if loca4 = 0 then
		goto .Lcompile_line_return
	end;

	loca12 := 0x6669 (* if *);
	loca4 := _memcmp(loca16, @loca12, 2);
	if loca4 = 0 then
		goto .Lcompile_line_if
	end;

	(* . *)
	if loca0 = 0x2e then
		goto .Lcompile_line_label
	end;
	(* _ *)
	if loca0 = 0x5f then
		goto .Lcompile_line_identifier
	end;
	goto .Lcompile_line_unchanged (* Else. *);

	.Lcompile_line_if;
	_compile_if();
	goto .Lcompile_line_section;

	.Lcompile_line_label;
	_compile_label(loca84);
	goto .Lcompile_line_section;

	.Lcompile_line_return;
	_compile_return();
	goto .Lcompile_line_section;

	.Lcompile_line_goto;
	_compile_goto();
	goto .Lcompile_line_section;

	.Lcompile_line_import;
	_compile_import();
	goto .Lcompile_line_section;

	.Lcompile_line_identifier;
	_compile_identifier();
	goto .Lcompile_line_section;

	.Lcompile_line_exit;
	_compile_exit();
	goto .Lcompile_line_section;

	.Lcompile_line_begin;

	if loca80 = 1 then
		goto .Lcompile_line_compile_entry
	end;
	_compile_text_section();
	.Lcompile_line_compile_entry;
	_compile_entry_point();
	loca8 := 1;
	goto .Lcompile_line_end;

	.Lcompile_line_const;
	_compile_constant_section();
	goto .Lcompile_line_section;

	.Lcompile_line_procedure;
	if loca80 = 1 then
		goto .Lcompile_line_compile_procedure
	end;
	_compile_text_section();
	.Lcompile_line_compile_procedure;
	_compile_procedure();
	loca8 := 1;
	goto .Lcompile_line_end;

	.Lcompile_line_var;
	_compile_variable_section();
	goto .Lcompile_line_section;

	.Lcompile_line_program;
	_compile_program();
	goto .Lcompile_line_section;

	.Lcompile_line_comment;
	_skip_comment(loca84);
	goto .Lcompile_line_section;

	.Lcompile_line_empty;
	_advance(1);
	goto .Lcompile_line_section;

	.Lcompile_line_unchanged;
	_compile_assembly(loca84);
	goto .Lcompile_line_section;

	.Lcompile_line_section;
	loca8 := 0;

	.Lcompile_line_end;
	_skip_spaces();
	_skip_comment();

	return loca8
end

(* Prints ".section .text" and exits. *)
proc _compile_text_section()
var loca0: Word
begin
	(* .section .text *)
	loca0 := 0x6365732e (* .sec *);
	_write_out(@loca0, 4);
	loca0 := 0x6e6f6974 (* tion *);
	_write_out(@loca0, 4);
	loca0 := 0x65742e20 (* _.te *);
	_write_out(@loca0, 4);
	loca0 := 0x0a7478 (* xt\n *);
	_write_out(@loca0, 3)
end

proc _compile_entry_point()
var loca0: Word
begin
	(* .type _start, @function *)
	loca0 := 0x7079742e (* .typ *);
	_write_out(@loca0, 4);
	loca0 := 0x735f2065 (* e _s *);
	_write_out(@loca0, 4);
	loca0 := 0x74726174 (* tart *);
	_write_out(@loca0, 4);
	loca0 := 0x6640202c (* , @f *);
	_write_out(@loca0, 4);
	loca0 := 0x74636e75 (* unct *);
	_write_out(@loca0, 4);
	loca0 := 0x0a6e6f69 (* ion\n *);
	_write_out(@loca0, 4);
	loca0 := 0x6174735f (* _sta *);
	_write_out(@loca0, 4);
	loca0 := 0x0a3a7472 (* rt:\n *);
	_write_out(@loca0, 4);

	_advance(6) (* Skip begin\n. *)
end

proc _compile_exit()
var loca0: Word
begin
	(* li a0, 0 *)
	(* li a7, SYS_EXIT *)
	(* ecall *)
	loca0 := 0x6120696c (* li a *);
	_write_out(@loca0, 4);
	loca0 := 0x30202c30 (* 0, 0 *);
	_write_out(@loca0, 4);
	loca0 := 0x20696c0a (* \nli_ *);
	_write_out(@loca0, 4);
	loca0 := 0x202c3761 (* a7,_ *);
	_write_out(@loca0, 4);
	loca0 := 0x650a3339 (* 93\ne *);
	_write_out(@loca0, 4);
	loca0 := 0x6c6c6163 (* call *);
	_write_out(@loca0, 4);
	loca0 := 0x0a (* \n *);
	_write_out(@loca0, 1);

	_advance(4) (* Skip end. *);
	_skip_spaces() (* Read the possible new line at the end of the file. *)
end

(* Finds the end of the line and returns its length in a0. *)
proc _read_line()
var
	loca0: ^Byte
	loca4: Byte
begin
	loca0 := _current() (* Local position in the source text. *);

	.Lread_line_do;
	loca4 := _front(loca0) (* t1 = Current character. *);
	if loca4 = 0 then
		goto .Lread_line_end (* Exit the loop on the NUL character. *)
	end;
	if loca4 = 0x0a then
		goto .Lread_line_end (* Exit the loop on the new line. *)
	end;
	loca0 := loca0 + 1;
	goto .Lread_line_do;

	.Lread_line_end;
	loca4 := _current();
	return loca0 - loca4 (* Return the line length. *)
end

proc _compile()
var
	loca0, loca4: Word
	loca8: Bool
	loca12: Char
	loca16: ^Byte
begin
	loca4 := 0 (* Whether the text section header was already emitted. *);

	.Lcompile_do;
	loca16 := _current();
	loca12 := _front(loca16) (* t0 = Current character. *);

	if loca12 = 0 then
		goto .Lcompile_end (* Exit the loop on the NUL character. *)
	end;

	_skip_spaces();
	loca0 := _read_line();
	loca8 := _compile_line(loca0, loca4);

	if loca8 = 0 then
		goto .Lcompile_do
	end;
	(* Update whether the text section header was already emitted. *)
	loca4 := loca4 or loca8;

	goto .Lcompile_do;
	.Lcompile_end
end

(* Returns the pointer to the current position in the source text in a0. *)
proc _current()
begin
	return s1
end

(* a0 is the number of bytes to advance in the source text. *)
proc _advance(loca84: Word)
begin
	s1 := s1 + loca84
end

(*
a0 - Pointer to an array to get the first element.

Returns the first character in the remaining source text.
*)
proc _front(loca84: ^Word)
begin
	return _get(loca84) & 0xff
end

proc _main()
begin
	(* Read the source from the standard input. *)
	_read_file(source_code, SOURCE_BUFFER_SIZE);

	s2 := 1
end

(* Entry point. *)
begin
	_main();
	_compile()
end.