started work on block read abstraction

src/dos_m65/unit_disk/disk_xx_cmd_read.s

@@ -0,0 +1,23 @@
+
+;
+; Read more data into the buffer
+;
+
+
+disk_xx_cmd_READ:
+
+    ldx PAR_FSINSTANCE
+	lda XX_MODE, x
+	cmp #$03
+	+beq fs_cbm_nextfileblock
+
+	; Reading directory
+
+	lda XX_DIR_PHASE, x
+	cmp #$01
+	+beq fs_cbm_read_dir
+	cmp #$02
+	+beq fs_cbm_read_dir_blocksfree
+
+	sec ; mark EOI
+	rts