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

- 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.
*)
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

proc _build_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 .Lbuild_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 .Lbuild_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 .Lbuild_identifier_expression_end
	end

	.Lbuild_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

	_build_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 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
		goto .Lcompile_identifier_assign
	end

	if _front(loca12) = 0x28 then
		goto .Lcompile_identifier_call
	end

	goto .Lcompile_identifier_end

	.Lcompile_identifier_call
	_compile_call(loca20, loca16)

	goto .Lcompile_identifier_end

	.Lcompile_identifier_assign
	_build_binary_expression()

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

	loca20 := loca20 + 4
	loca16 := loca16 - 4
	_write_out(loca20, loca16)

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

	goto .Lcompile_identifier_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) = 0 then
		goto .Ltoken_character_end
	end
	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
	goto .Ltoken_character_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) = 0 then
		goto .Lcompile_constant_section_end
	end

	_compile_constant()
	goto .Lcompile_constant_section_item

	.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()
	_write_out(loca0, loca84)

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

	loca0 := _front(loca0)
	if loca0 = 0x3a then
		goto .Lcompile_label_colon
	end

	_put_char(0x3a) (* : *)

	.Lcompile_label_colon
	_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. *)
	addi 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

	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
	add s1, s1, a0
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)

	addi s2, zero, 1
end

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