Add my homegrown cross compiler scripts

1 files changed, 152 insertions, 220 deletions

diff --git a/boot/stage1.s b/boot/stage1.s
index c86e872..b32815d 100644
--- a/boot/stage1.s
+++ b/boot/stage1.s
@@ -4,9 +4,29 @@
 
 .global _start # Program entry point.
 
+#
 # Registers used as global variables:
 # 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.
 
 .include "boot/definitions.inc"
 
@@ -73,9 +93,6 @@ _compile_import:
 	addi s0, sp, 24
 
 .Lcompile_import_loop:
-	call _skip_comment
-	call _skip_spaces
-
 	mv a0, s1
 	addi a1, sp, 0
 	call _tokenize_next
@@ -106,7 +123,6 @@ _build_binary_expression:
 
 	li a0, 0
 	call _build_expression
-	call _skip_spaces
 
 	mv a0, s1
 	addi a1, sp, 12
@@ -114,26 +130,26 @@ _build_binary_expression:
 	lw t0, 12(sp)
 
 	li t1, TOKEN_AND
-	beq t0, t1, .L_build_binary_expression_and
+	beq t0, t1, .Lbuild_binary_expression_and
 
 	li t1, TOKEN_OR
-	beq t0, t1, .L_build_binary_expression_or
+	beq t0, t1, .Lbuild_binary_expression_or
 
 	li t1, TOKEN_PLUS
-	beq t0, t1, .L_build_binary_expression_plus
+	beq t0, t1, .Lbuild_binary_expression_plus
 
 	li t1, TOKEN_EQUALS
-	beq t0, t1, .L_build_binary_expression_equal
+	beq t0, t1, .Lbuild_binary_expression_equal
 
 	li t1, TOKEN_ASTERISK
-	beq t0, t1, .L_build_binary_expression_product
+	beq t0, t1, .Lbuild_binary_expression_product
 
 	li t1, TOKEN_MINUS
-	beq t0, t1, .L_build_binary_expression_minus
+	beq t0, t1, .Lbuild_binary_expression_minus
 
 	j .Lbuild_binary_expression_end
 
-.L_build_binary_expression_equal:
+.Lbuild_binary_expression_equal:
 	mv s1, a0 # Skip =.
 	li a0, 1
 	call _build_expression
@@ -147,7 +163,7 @@ _build_binary_expression:
 
 	j .Lbuild_binary_expression_end
 
-.L_build_binary_expression_and:
+.Lbuild_binary_expression_and:
 	mv s1, a0 # Skip &.
 	li a0, 1
 	call _build_expression
@@ -157,7 +173,7 @@ _build_binary_expression:
 
 	j .Lbuild_binary_expression_end
 
-.L_build_binary_expression_or:
+.Lbuild_binary_expression_or:
 	mv s1, a0 # Skip or.
 	li a0, 1
 	call _build_expression
@@ -167,7 +183,7 @@ _build_binary_expression:
 
 	j .Lbuild_binary_expression_end
 
-.L_build_binary_expression_plus:
+.Lbuild_binary_expression_plus:
 	mv s1, a0 # Skip +.
 	li a0, 1
 	call _build_expression
@@ -177,7 +193,7 @@ _build_binary_expression:
 
 	j .Lbuild_binary_expression_end
 
-.L_build_binary_expression_minus:
+.Lbuild_binary_expression_minus:
 	mv s1, a0 # Skip -.
 	li a0, 1
 	call _build_expression
@@ -187,7 +203,7 @@ _build_binary_expression:
 
 	j .Lbuild_binary_expression_end
 
-.L_build_binary_expression_product:
+.Lbuild_binary_expression_product:
 	mv s1, a0 # Skip *.
 	li a0, 1
 	call _build_expression
@@ -448,7 +464,6 @@ _build_expression:
 	call _write_out
 
 	addi s1, s1, 1 # Skip @.
-	call _skip_spaces
 	call _read_token
 	sw s1, 32(sp)
 	sw a0, 28(sp)
@@ -654,7 +669,6 @@ _compile_call:
 	sw zero, 12(sp) # Argument count for a procedure call.
 
 .Lcompile_call_paren:
-	call _skip_spaces
 	lbu t0, (s1)
 	li t1, 0x29 # )
 	beq t0, t1, .Lcompile_call_complete
@@ -688,7 +702,6 @@ _compile_call:
 	li a1, 5
 	call _write_out
 
-	call _skip_spaces
 	lbu t0, (s1)
 	li t1, ','
 	bne t0, t1, .Lcompile_call_paren
@@ -726,7 +739,6 @@ _compile_call:
 	li a0, '\n'
 	call _put_char
 
-	call _skip_spaces
 	addi s1, s1, 1 # Skip the close paren.
 
 	# Epilogue.
@@ -912,7 +924,6 @@ _compile_procedure_section:
 .Lcompile_procedure_section_loop:
 	call _skip_spaces
 	call _skip_comment
-	call _skip_spaces
 
 	mv a0, s1
 	addi a1, sp, 4
@@ -945,7 +956,6 @@ _compile_module_declaration:
 	call _write_out
 
 	# Skip "program".
-	call _skip_comment
 	mv a0, s1
 	addi a1, sp, 4
 	call _tokenize_next
@@ -965,9 +975,6 @@ _compile_constant_section:
 	sw s0, 16(sp)
 	addi s0, sp, 24
 
-	call _skip_comment
-	call _skip_spaces
-
 	mv a0, s1
 	addi a1, sp, 4
 	call _tokenize_next
@@ -999,25 +1006,22 @@ _compile_constant_section:
 .type _compile_constant, @function
 _compile_constant:
 	# Prologue.
-	addi sp, sp, -24
-	sw ra, 20(sp)
-	sw s0, 16(sp)
-	addi s0, sp, 24
+	addi sp, sp, -32
+	sw ra, 28(sp)
+	sw s0, 24(sp)
+	addi s0, sp, 32
 
 	mv a0, s1
-	addi a1, sp, 4
+	addi a1, sp, 12
 	call _tokenize_next
-
-	sub a1, a0, s1 # The identifier end from _tokenize_next should be in a0.
-	mv a0, s1
-	add s1, s1, a1 # Save the identifier pointer before advancing it.
+	addi a1, sp, 0
+	call _tokenize_next # Skip the assignment sign.
+	mv s1, a0
+	# Write identifier the identifier.
+	lw a0, 20(sp)
+	lw a1, 16(sp)
 	call _write_out
 
-	mv a0, s1
-	addi a1, sp, 4
-	call _tokenize_next
-	mv s1, a0 # Skip the assignment sign.
-
 	# : .long
 	li t0, 0x20676e6f # ong_
 	sw t0, 4(sp)
@@ -1027,21 +1031,23 @@ _compile_constant:
 	li a1, 8
 	call _write_out
 
-	call _skip_spaces
-	call _read_token
+	mv a0, s1
+	addi a1, sp, 12
+	call _tokenize_next
+	mv s1, a0
 
-	mv a1, a0 # The literal length from _read_token should be in a1.
-	mv a0, s1 # Save the literal pointer before advancing it.
-	add s1, s1, a1
+	lw a0, 20(sp) # Save the literal pointer before advancing it.
+	lw a1, 16(sp) # The literal length.
 	call _write_out
 
 	li a0, '\n'
 	call _put_char
+	call _skip_spaces
 
 	# Epilogue.
-	lw ra, 20(sp)
-	lw s0, 16(sp)
-	addi sp, sp, 24
+	lw ra, 28(sp)
+	lw s0, 24(sp)
+	addi sp, sp, 32
 	ret
 
 .type _compile_variable_section, @function
@@ -1080,6 +1086,7 @@ _compile_variable_section:
 	addi sp, sp, 24
 	ret
 
+# Compile a global variable.
 .type _compile_variable, @function
 _compile_variable:
 	# Prologue.
@@ -1088,32 +1095,33 @@ _compile_variable:
 	sw s0, 40(sp)
 	addi s0, sp, 48
 
-	call _read_token
-
 	# Save the identifier on the stack since it should emitted multiple times.
-	sw s1, 36(sp)
-	sw a0, 32(sp)
-	add s1, s1, a0
-
-	call _skip_spaces
-	addi s1, s1, 1 # Skip the colon in front of the type.
-
-	call _skip_spaces
-	addi s1, s1, 1 # Skip the opening bracket.
-
-	call _read_token
+	mv a0, s1
+	addi a1, sp, 28
+	call _tokenize_next
+	addi a1, sp, 4
+	call _tokenize_next # Skip the colon in front of the type.
+	addi a1, sp, 4
+	call _tokenize_next # Skip the opening bracket.
+	addi a1, sp, 16
+	call _tokenize_next # Save the array size on the stack since it has to be emitted multiple times.
+	addi a1, sp, 4
+	call _tokenize_next # Skip the closing bracket.
+	addi a1, sp, 4
+	call _tokenize_next # Skip the type.
+	mv s1, a0
 
-	# Save the array size on the stack since it has to be emitted multiple times.
-	sw s1, 28(sp)
+	/* DEBUG
+	lw a0, 24(sp)
+	add a0, a0, '0'
 	sw a0, 24(sp)
-	add s1, s1, a0
-
-	call _skip_spaces
-	addi s1, s1, 1 # Skip the closing bracket.
-
-	call _skip_spaces
-	call _read_token
-	add s1, s1, a0 # Skip the type.
+	addi a0, sp, 24
+	li a1, 1
+	call _write_error
+	lw a0, 28(sp)
+	li a1, 8
+	call _write_error
+	*/
 
 	# .type identifier, @object
 	la a0, asm_type
@@ -1134,15 +1142,15 @@ _compile_variable:
 	call _write_out
 
 	li t0, 0x206f7265 # ero_
-	sw t0, 20(sp)
+	sw t0, 12(sp)
 	li t0, 0x7a2e203a # : .z
-	sw t0, 16(sp)
-	addi a0, sp, 16
+	sw t0, 8(sp)
+	addi a0, sp, 8
 	li a1, 8
 	call _write_out
 
-	lw a0, 28(sp)
-	lw a1, 24(sp)
+	lw a0, 24(sp)
+	lw a1, 20(sp)
 	call _write_out
 
 	li a0, '\n'
@@ -1215,9 +1223,6 @@ _compile_procedure:
 
 	# Generate the body of the procedure.
 .Lcompile_procedure_body:
-	call _skip_spaces
-	call _read_line
-	sw a0, 12(sp)
 	li t0, 0x0a646e65 # end\n
 	sw t0, 8(sp)
 	mv a0, s1
@@ -1227,7 +1232,6 @@ _compile_procedure:
 
 	beqz a0, .Lcompile_procedure_end
 
-	lw a0, 12(sp)
 	call _compile_statement
 	j .Lcompile_procedure_body
 
@@ -1245,111 +1249,95 @@ _compile_procedure:
 	addi sp, sp, 32
 	ret
 
+# Compiles a goto statement to an uncoditional jump.
 .type _compile_goto, @function
 _compile_goto:
 	# Prologue.
-	addi sp, sp, -16
-	sw ra, 12(sp)
-	sw s0, 8(sp)
-	addi s0, sp, 16
+	addi sp, sp, -32
+	sw ra, 28(sp)
+	sw s0, 24(sp)
+	addi s0, sp, 32
 
-	addi s1, s1, 4 # Skip the goto keyword.
+	mv a0, s1
+	addi a1, sp, 0
+	call _tokenize_next # Skip the goto keyword.
+	addi a1, sp, 0
+	call _tokenize_next # We should be on dot the label is beginning with.
+	addi a1, sp, 0
+	call _tokenize_next# Save the label name.
+	mv s1, a0
 
-	li t0, 0x206a # j_
-	sw t0, 8(sp)
-	addi a0, sp, 8
-	li a1, 2
+	li t0, 0x2e206a # j .
+	sw t0, 12(sp)
+	addi a0, sp, 12
+	li a1, 3
 	call _write_out
 
-	call _skip_spaces
-	sw s1, 8(sp) # We should be on dot the label is beginning with.
-	addi s1, s1, 1
-
-	call _read_token
-	add s1, s1, a0
-	addi a1, a0, 1 # Label length and the dot.
 	lw a0, 8(sp) # Saved dot position.
+	lw a1, 4(sp)
 	call _write_out
 
-	addi s1, s1, 1 # Skip the new line.
-
 	li a0, '\n'
 	call _put_char
 
 	# Epilogue.
-	lw ra, 12(sp)
-	lw s0, 8(sp)
-	addi sp, sp, 16
+	lw ra, 28(sp)
+	lw s0, 24(sp)
+	addi sp, sp, 32
 	ret
 
-# a0 - Line length.
+# Rewrites a label to assembly.
 .type _compile_label, @function
 _compile_label:
 	# Prologue.
-	addi sp, sp, -16
-	sw ra, 12(sp)
-	sw s0, 8(sp)
-	addi s0, sp, 16
-
-	sw a0, 0(sp) # Save the line length.
-	mv a1, a0 # Argument for _write_out later.
-
-	lw t0, 0(sp) # Line length.
-	mv t1, s1 # Line start.
-
-	add t1, t1, t0
-	addi t1, t1, -1 # Last character on the line.
-
-	lbu t1, (t1)
-	li t2, ';'
-	bne t1, t2, .Lcompile_label_colon
-
-	addi a1, a1, -1
+	addi sp, sp, -32
+	sw ra, 28(sp)
+	sw s0, 24(sp)
+	addi s0, sp, 32
 
-.Lcompile_label_colon:
-	# Write the whole line as is.
 	mv a0, s1
-	call _write_out
-
-	li t0, 0x3a # :
-	sw t0, 4(sp)
-	addi a0, sp, 4
-	li a1, 1
-	call _write_out
+	addi a1, sp, 8
+	call _tokenize_next # Dot starting the label.
+	addi a1, sp, 8
+	call _tokenize_next
+	mv s1, a0
 
-	li t0, '\n'
-	sw t0, 4(sp)
-	addi a0, sp, 4
-	li a1, 1
+	li a0, '.'
+	call _put_char
+	lw a0, 16(sp)
+	lw a1, 12(sp)
 	call _write_out
-
-	lw a0, 0(sp)
-	addi a0, a0, 1 # Skip the new line as well.
-	add s1, s1, a0 # Skip the line.
+	li a0, ':'
+	call _put_char
+	li a0, '\n'
+	call _put_char
 
 	# Epilogue.
-	lw ra, 12(sp)
-	lw s0, 8(sp)
-	addi sp, sp, 16
+	lw ra, 28(sp)
+	lw s0, 24(sp)
+	addi sp, sp, 32
 	ret
 
+# Just skips the return keyword and evaluates the return expression.
 .type _compile_return, @function
 _compile_return:
 	# Prologue.
-	addi sp, sp, -16
-	sw ra, 12(sp)
-	sw s0, 8(sp)
-	addi s0, sp, 16
+	addi sp, sp, -32
+	sw ra, 28(sp)
+	sw s0, 24(sp)
+	addi s0, sp, 32
 
-	addi s1, s1, 6 # Skip return.
-	call _skip_spaces
+	mv a0, s1
+	addi a1, sp, 12
+	call _tokenize_next
+	mv s1, a0 # Skip return.
 
 	call _build_binary_expression
 
 	# Epilogue.
-	lw ra, 12(sp)
-	lw s0, 8(sp)
-	addi sp, sp, 16
+	lw ra, 28(sp)
+	lw s0, 24(sp)
+	addi sp, sp, 32
 	ret
 
 .type _compile_if, @function
@@ -1403,8 +1391,6 @@ _compile_if:
 	li t1, TOKEN_END
 	beq t0, t1, .Lcompile_if_end
 
-	call _read_line
-	li a1, 1
 	call _compile_statement
 
 	j .Lcompile_if_loop
@@ -1422,7 +1408,7 @@ _compile_if:
 	call _printi
 
 	# Finalize the label.
-	li t0, 0x0a3a # :\n:\n
+	li t0, 0x0a3a # :\n
 	sh t0, 16(sp)
 	addi a0, sp, 16
 	li a1, 2
@@ -1436,11 +1422,7 @@ _compile_if:
 	addi sp, sp, 32
 	ret
 
-# Parameters:
-# a0 - Line length.
-#
-# 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.
+# Checks for the type of the current statement and compiles it.
 .type _compile_statement, @function
 _compile_statement:
 	# Prologue.
@@ -1449,42 +1431,17 @@ _compile_statement:
 	sw s0, 24(sp)
 	addi s0, sp, 32
 
-	# Preserve passed arguments.
-	sw a0, 20(sp)
-
-	mv a0, s1
-	lw a1, 20(sp)
-	call _is_local_identifier
-	bnez a0, .Lcompile_statement_identifier
-
-	mv a0, s1
-	li a1, 2
-	call _is_register_identifier
-	bnez a0, .Lcompile_statement_identifier
-
-	li t0, 0x6f746f67 # goto
-	sw t0, 12(sp)
-	mv a0, s1
-	addi a1, sp, 12
-	li a2, 4
-	call _memcmp
-	beqz a0, .Lcompile_statement_goto
-
-	call _skip_comment
-	/* DEBUG
-	mv a0, s1
-	li a1, 4
-	call _write_error
-	mv a0, s1
-	li a1, 4
-	call _write_error
-	*/
-
 	mv a0, s1
 	addi a1, sp, 0
 	call _tokenize_next
 	lw t0, 0(sp)
 
+	li t1, TOKEN_IDENTIFIER
+	beq t0, t1, .Lcompile_statement_identifier
+
+	li t1, TOKEN_GOTO
+	beq t0, t1, .Lcompile_statement_goto
+
 	li t1, TOKEN_RETURN
 	beq t0, t1, .Lcompile_statement_return
 
@@ -1494,10 +1451,6 @@ _compile_statement:
 	li t1, TOKEN_DOT
 	beq t0, t1, .Lcompile_statement_label
 
-	lbu t0, (s1)
-	li t1, '_'
-	beq t0, t1, .Lcompile_statement_identifier
-
 	j .Lcompile_statement_empty # Else.
 
 .Lcompile_statement_if:
@@ -1505,7 +1458,6 @@ _compile_statement:
 	j .Lcompile_statement_end
 
 .Lcompile_statement_label:
-	lw a0, 20(sp)
 	call _compile_label
 	j .Lcompile_statement_end
 
@@ -1527,7 +1479,6 @@ _compile_statement:
 
 .Lcompile_statement_end:
 	sw a0, 12(sp)
-	call _skip_spaces
 	call _skip_comment
 	lw a0, 12(sp)
 
@@ -1559,10 +1510,10 @@ _compile_text_section:
 .type _compile_entry_point, @function
 _compile_entry_point:
 	# Prologue.
-	addi sp, sp, -8
-	sw ra, 4(sp)
-	sw s0, 0(sp)
-	addi s0, sp, 8
+	addi sp, sp, -32
+	sw ra, 28(sp)
+	sw s0, 24(sp)
+	addi s0, sp, 32
 
 	# .type _start, @function
 	la a0, asm_start
@@ -1581,7 +1532,6 @@ _compile_entry_point:
 	li t1, TOKEN_END
 	beq t0, t1, .Lcompile_entry_point_end
 
-	lw a0, 12(sp)
 	call _compile_statement
 	j .Lcompile_entry_point_body
 
@@ -1593,27 +1543,9 @@ _compile_entry_point:
 	call _write_out
 
 	# Epilogue.
-	lw ra, 4(sp)
-	lw s0, 0(sp)
-	addi sp, sp, 8
-	ret
-
-# Finds the end of the line and returns its length in a0.
-.type _read_line, @function
-_read_line:
-	mv t0, s1 # Local position in the source text.
-
-.Lread_line_do:
-	lbu t1, (t0) # t1 = Current character.
-	beqz t1, .Lread_line_end # Exit the loop on the NUL character.
-	li t2, '\n'
-	beq t1, t2, .Lread_line_end # Exit the loop on the new line.
-
-	addi t0, t0, 1
-	j .Lread_line_do
-
-.Lread_line_end:
-	sub a0, t0, s1 # Return the line length.
+	lw ra, 28(sp)
+	lw s0, 24(sp)
+	addi sp, sp, 32
 	ret
 
 .type _compile, @function