improved support for different RAM configurations

src/dos_m65/utils/util_check_rd_ram.s

@@ -0,0 +1,21 @@
+
+; If no Hyper RAM is present, clear the RAM DISK device number and set Carry
+
+
+util_check_rd_ram:
+
+	lda RAM_ATTIC
+	ora RAM_CELLAR
+	beq @no_hyperram
+
+	clc
+	rts
+
+
+@no_hyperram:
+
+	lda #$00
+	sta UNIT_RAMDISK
+
+	sec
+	rts