work towards directory filtering in CBDOS

src/dos_m65/utils/util_dir_filter.s

@@ -0,0 +1,28 @@
+
+; Check if file name matches the filter (if so - Zero flag set)
+
+
+util_dir_filter:
+
+	lda PAR_FPATTERN
+	cmp #$A0
+	beq @done                          ; branch if no filter
+
+	ldy #$00
+
+@lp1:
+
+	lda PAR_FPATTERN, y
+	cmp #'*'
+	beq @done                          ; branch on wildcard
+
+	cmp PAR_FNAME, y
+	bne @done                          ; branch if does not match
+
+	iny
+	cpy #$10
+	bne @lp1                           ; next iteration if maximum length not reached
+
+@done:
+
+	rts