some work towards 2nd floppy

src/dos_m65/dos_unitnum.s

@@ -20,8 +20,10 @@ dos_UNITNUM:
 	cmp #$00
 	beq dos_UNITNUM_sdcard
 	cmp #$01
-	beq dos_UNITNUM_floppy
+	beq dos_UNITNUM_floppy0
 	cmp #$02
+	beq dos_UNITNUM_floppy1
+	cmp #$03
 	beq dos_UNITNUM_ramdisk
 
 	; FALLTROUGH
@@ -37,9 +39,14 @@ dos_UNITNUM_sdcard:
 	lda UNIT_SDCARD
 	bra dos_UNITNUM_common
 
-dos_UNITNUM_floppy:
+dos_UNITNUM_floppy0:
 
-	lda UNIT_FLOPPY
+	lda UNIT_FLOPPY0
+	bra dos_UNITNUM_common
+
+dos_UNITNUM_floppy1:
+
+	lda UNIT_FLOPPY1
 	bra dos_UNITNUM_common
 
 dos_UNITNUM_ramdisk: