Add semicolons separating the statements

boot/stage1.s

@@ -207,11 +207,66 @@ _build_binary_expression:
 	addi sp, sp, 32
 	ret
 
+# Checks whether the given identifier starts with "loca".
+# Parameters:
+# a0 - Pointer to the identifier.
+# a1 - Identifier length.
+#
+# Sets a0 to 1 if the identifier starts with "loca", otherwise to 0.
+.type _is_local_identifier, @function
+_is_local_identifier:
+	# Prologue.
+	addi sp, sp, -16
+	sw ra, 12(sp)
+	sw s0, 8(sp)
+	addi s0, sp, 16
+
+	li t0, 0x61636f6c # loca
+	sw t0, 4(sp)
+	# a0 is already set.
+	addi a1, sp, 4
+	li a2, 4
+	call _memcmp
+	seqz a0, a0
+
+	# Epilogue.
+	lw ra, 12(sp)
+	lw s0, 8(sp)
+	addi sp, sp, 16
+	ret
+
+# Checks whether the given identifier is a saved register name, like s1 or s2.
+# Parameters:
+# a0 - Pointer to the identifier.
+# a1 - Identifier length.
+#
+# Sets a0 to 1 if the identifier is a preserved register, otherwise to 0.
+.type _is_register_identifier, @function
+_is_register_identifier:
+	# Prologue.
+	addi sp, sp, -8
+	sw ra, 4(sp)
+	sw s0, 0(sp)
+	addi s0, sp, 8
+
+	lbu a0, (a0)
+	addi a1, a1, -2
+	seqz a1, a1
+	addi t0, a0, -'s'
+	seqz t0, t0
+	and a0, a1, t0
+
+	# Epilogue.
+	lw ra, 4(sp)
+	lw s0, 0(sp)
+	addi sp, sp, 8
+	ret
+
 # Parameters:
 # a0 - Identifier length.
 # a1 - Register number as character.
-.type _build_identifier_expression, @function
-_build_identifier_expression:
+.type _compile_identifier_expression, @function
+_compile_identifier_expression:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -221,22 +276,15 @@ _build_identifier_expression:
 	sw a0, 20(sp) # Identifier length.
 	sw a1, 16(sp) # Register number as character.
 
-	li t0, 0x61636f6c # loca
-	sw t0, 12(sp)
 	mv a0, s1
-	addi a1, sp, 12
-	li a2, 4
-	call _memcmp
-	beqz a0, .Lbuild_identifier_expression_local
+	lw a1, 20(sp)
+	call _is_local_identifier
+	bnez a0, .Lcompile_identifier_expression_local
 
-	lbu a0, (s1)
-	lw t0, 20(sp) 
-	addi t0, t0, -2
-	seqz t0, t0
-	addi t1, a0, -'s'
-	seqz t1, t1
-	and t0, t0, t1
-	bnez t0, .Lbuild_identifier_expression_saved
+	mv a0, s1
+	lw a1, 20(sp)
+	call _is_register_identifier
+	bnez a0, .Lcompile_identifier_expression_saved
 
 	# Global identifier.
 	lw t1, 16(sp)
@@ -258,7 +306,7 @@ _build_identifier_expression:
 
 	lbu a0, (s1)
 	call _is_upper
-	beqz a0, .Lbuild_identifier_expression_end
+	beqz a0, .Lcompile_identifier_expression_end
 
 	lw t1, 16(sp)
 	li t0, 0x0a290061 # a\0)\n
@@ -274,9 +322,9 @@ _build_identifier_expression:
 	li a1, 12
 	call _write_out
 
-	j .Lbuild_identifier_expression_end
+	j .Lcompile_identifier_expression_end
 
-.Lbuild_identifier_expression_saved:
+.Lcompile_identifier_expression_saved:
 	li t0, 0x00202c00 # \0,_
 	lw t1, 16(sp)
 	or t0, t0, t1
@@ -294,9 +342,9 @@ _build_identifier_expression:
 	li a0, '\n'
 	call _put_char
 
-	j .Lbuild_identifier_expression_end
+	j .Lcompile_identifier_expression_end
 
-.Lbuild_identifier_expression_local:
+.Lcompile_identifier_expression_local:
 	lw t1, 16(sp)
 	li t0, 0x00202c00 # \0,_
 	or t0, t0, t1
@@ -321,9 +369,9 @@ _build_identifier_expression:
 	li a0, '\n'
 	call _put_char
 
-	j .Lbuild_identifier_expression_end
+	j .Lcompile_identifier_expression_end
 
-.Lbuild_identifier_expression_end:
+.Lcompile_identifier_expression_end:
 
 	# Epilogue.
 	lw ra, 28(sp)
@@ -368,7 +416,7 @@ _build_expression:
 
 	lw a0, 20(sp)
 	lw a1, 28(sp)
-	call _build_identifier_expression
+	call _compile_identifier_expression
 
 	j .Lbuild_expression_advance
 
@@ -455,6 +503,86 @@ _build_expression:
 	addi sp, sp, 40
 	ret
 
+# Compiles an lvalue.
+#
+# Parameters:
+# a0 - Pointer to the identifier.
+# a1 - Identifier length.
+.type _compile_designator_expression, @function
+_compile_designator_expression:
+	# Prologue.
+	addi sp, sp, -32
+	sw ra, 28(sp)
+	sw s0, 24(sp)
+	addi s0, sp, 32
+
+	sw a0, 20(sp) # Identifier pointer.
+	sw a1, 16(sp) # Identifier length.
+
+	lw a0, 20(sp)
+	lw a1, 16(sp)
+	call _is_local_identifier
+	bnez a0, .Lcompile_designator_expression_local
+
+	lw a0, 20(sp)
+	lw a1, 16(sp)
+	call _is_register_identifier
+	bnez a0, .Lcompile_designator_expression_saved
+
+.Lcompile_designator_expression_local:
+	li t0, 0x202c30 # 0,_
+	sw t0, 12(sp)
+	li t0, 0x61207773 # sw a
+	sw t0, 8(sp)
+	addi a0, sp, 8
+	li a1, 7
+	call _write_out
+
+	lw a0, 20(sp)
+	lw a1, 16(sp)
+	addi a0, a0, 4 # Skip the "loca" variable prefix.
+	addi a1, a1, -4 # Skip the "loca" variable prefix.
+	call _write_out
+
+	li t0, '\n'
+	sw t0, 12(sp)
+	li t0, 0x29707328 # (sp)
+	sw t0, 8(sp)
+	addi a0, sp, 8
+	li a1, 5
+	call _write_out
+
+	j .Lcompile_designator_expression_end
+
+.Lcompile_designator_expression_saved:
+	li t0, 0x20766d # mv_
+	sw t0, 12(sp)
+	addi a0, sp, 12
+	li a1, 3
+	call _write_out
+
+	lw a0, 20(sp)
+	lw a1, 16(sp)
+	call _write_out
+
+	li t0, 0x0a # \n
+	sw t0, 12(sp)
+	li t0, 0x3061202c # , a0
+	sw t0, 8(sp)
+	addi a0, sp, 8
+	li a1, 5
+	call _write_out
+
+	j .Lcompile_designator_expression_end
+
+.Lcompile_designator_expression_end:
+
+	# Epilogue.
+	lw ra, 28(sp)
+	lw s0, 24(sp)
+	addi sp, sp, 32
+	ret
+
 # Compiles a statement beginning with an identifier.
 #
 # Left values should be variables named "loca n", where n is the offset
@@ -508,28 +636,9 @@ _compile_identifier:
 
 .Lcompile_identifier_assign:
 	call _build_binary_expression
-
-	li t0, 0x202c30 # 0,_
-	sw t0, 12(sp)
-	li t0, 0x61207773 # sw a
-	sw t0, 8(sp)
-	addi a0, sp, 8
-	li a1, 7
-	call _write_out
-
 	lw a0, 20(sp)
 	lw a1, 16(sp)
-	addi a0, a0, 4 # Skip the "loca" variable prefix.
-	addi a1, a1, -4 # Skip the "loca" variable prefix.
-	call _write_out
-
-	li t0, '\n'
-	sw t0, 12(sp)
-	li t0, 0x29707328 # (sp)
-	sw t0, 8(sp)
-	addi a0, sp, 8
-	li a1, 5
-	call _write_out
+	call _compile_designator_expression
 
 	j .Lcompile_identifier_end
 
@@ -1310,11 +1419,7 @@ _compile_label:
 	addi s0, sp, 16
 
 	sw a0, 0(sp) # Save the line length.
-
-	# Write the whole line as is.
-	mv a0, s1
-	lw a1, 0(sp)
-	call _write_out
+	mv a1, a0 # Argument for _write_out later.
 
 	lw t0, 0(sp) # Line length.
 	mv t1, s1 # Line start.
@@ -1323,8 +1428,15 @@ _compile_label:
 	addi t1, t1, -1 # Last character on the line.
 
 	lbu t1, (t1)
-	li t2, ':'
-	beq t1, t2, .Lcompile_label_colon
+	li t2, ';'
+	bne t1, t2, .Lcompile_label_colon
+
+	addi a1, a1, -1
+
+.Lcompile_label_colon:
+	# Write the whole line as is.
+	mv a0, s1
+	call _write_out
 
 	li t0, 0x3a # :
 	sw t0, 4(sp)
@@ -1332,7 +1444,6 @@ _compile_label:
 	li a1, 1
 	call _write_out
 
-.Lcompile_label_colon:
 	li t0, '\n'
 	sw t0, 4(sp)
 	addi a0, sp, 4
@@ -1411,12 +1522,6 @@ _compile_if:
 	call _put_char
 
 .Lcompile_if_loop:
-	/* DEBUG
-	mv a0, s1
-	li a1, 6
-	call _write_error
-	call _divide_by_zero_error */
-
 	call _skip_spaces
 	call _read_token
 
@@ -1532,13 +1637,15 @@ _compile_line:
 	call _memcmp
 	beqz a0, .Lcompile_line_exit
 
-	li t0, 0x61636f6c # loca
-	sw t0, 12(sp)
 	mv a0, s1
-	addi a1, sp, 12
-	li a2, 4
-	call _memcmp
-	beqz a0, .Lcompile_line_identifier
+	lw a1, 20(sp)
+	call _is_local_identifier
+	bnez a0, .Lcompile_line_identifier
+
+	mv a0, s1
+	li a1, 2
+	call _is_register_identifier
+	bnez a0, .Lcompile_line_identifier
 
 	li t0, 0x6f706d69 # impo
 	sw t0, 12(sp)
@@ -1806,9 +1913,6 @@ _main:
 .type _start, @function
 _start:
 	call _tokenizer_initialize
-	li a1, 50
-	call _write_error
-
 	call _main
 	call _compile