Unify taking an identifier address

boot/common-boot.s

@@ -4,9 +4,9 @@
 
 .global _is_alpha, _is_digit, _is_alnum, _is_upper, _is_lower
 .global _write_s, _read_file, _write_error, _write_c, _write_i, _print_i
-.global _get, _memcmp, _memchr, _memmem, _memcpy
-.global _divide_by_zero_error, _exit, _mmap
-.global _strings_index, _string_equal
+.global _memcmp, _memchr, _memmem, _memcpy, _mmap
+.global _current, _get, _advance, _label_counter
+.global _divide_by_zero_error, _exit, _strings_index, _string_equal
 
 .section .rodata
 
@@ -598,3 +598,33 @@ _mmap:
 	ecall
 
 	ret
+
+# Sets the a0 to the current position in the source text (s1).
+.type _current, @function
+_current:
+	mv a0, s1
+	ret
+
+# Advances the position of the source text.
+#
+# Parameters:
+# a0 - The number of bytes to advance.
+.type _advance, @function
+_advance:
+	add s1, s1, a0
+	ret
+
+# Advances the global label counter by 1 setting a0 to the previous value.
+#
+# Parameters:
+# a0 - If it is 0, resets the counter to 1.
+.type _label_counter, @function
+_label_counter:
+	bnez a0, .Llabel_counter_advance
+	li s2, 0
+
+.Llabel_counter_advance:
+	mv a0, s2
+	addi s2, s2, 1
+
+	ret