Initial Nascom basic ecb-vdu graphics

set and reset for 80x25b screen with 256 character mod

Source/HBIOS/rf.asm

@@ -5,19 +5,19 @@
 ;
 ;
 ;
-RF_U0IO		.EQU	$A0
-RF_U1IO		.EQU	$A4
-RF_U2IO		.EQU	$A8
-RF_U3IO		.EQU	$AC
+RF_U0IO		.EQU	$A0		; BASED ADDRESS OF RAMFLOPPY 1
+RF_U1IO		.EQU	$A4		; BASED ADDRESS OF RAMFLOPPY 2
+RF_U2IO		.EQU	$A8		; BASED ADDRESS OF RAMFLOPPY 3
+RF_U3IO		.EQU	$AC		; BASED ADDRESS OF RAMFLOPPY 4
 ;
 ; IO PORT OFFSETS
 ;
-RF_DAT		.EQU	0
-RF_AL		.EQU	1
-RF_AH		.EQU	2
-RF_ST		.EQU	3
+RF_DAT		.EQU	0		; DATA IN/OUT ONLT TO SRAM      - R/W
+RF_AL		.EQU	1		; ADDRESS LOW FOR RAMF MEMORY   - W/O 
+RF_AH		.EQU	2		; ADDRESS HIGH FOR RAMF MEMORY  - W/O
+RF_ST		.EQU	3		; STATUS PORT			- R/O
 ;
-; MD DEVICE CONFIGURATION
+; RF DEVICE CONFIGURATION
 ;
 RF_DEVCNT	.EQU	RFCNT		; NUMBER OF RF DEVICES SUPPORTED
 RF_CFGSIZ	.EQU	8		; SIZE OF CFG TBL ENTRIES
@@ -177,7 +177,7 @@ RF_GEOM:
 RF_DEVICE:
 	LD	D,DIODEV_RF		; D := DEVICE TYPE
 	LD	E,(IY+RF_DEV)		; E := PHYSICAL DEVICE NUMBER
-	LD	C,%00110000		; C := ATTRIBUTES, NON-REMOVALBE RAM FLOPPY
+	LD	C,%00110000		; C := ATTRIBUTES, NON-REMOVABLE RAM FLOPPY
 	XOR	A			; SIGNAL SUCCESS
 	RET
 ;
@@ -294,14 +294,14 @@ RF_SETIO:
 ;
 ;
 ;
-RF_SETADR:
-	LD	A,(RF_IO)
-	OR	RF_AL
-	LD	C,A
-	LD	A,(IY+RF_LBA+0)
-	OUT	(C),A
-	LD	A,(IY+RF_LBA+1)
-	INC	C
+RF_SETADR:				; OUTPUT THE
+	LD	A,(RF_IO)		; LOGICAL BLOCK
+	OR	RF_AL			; ADDRESS TO THE
+	LD	C,A			; TO THE MSB AND
+	LD	A,(IY+RF_LBA+0)		; LSB SECTRK
+	OUT	(C),A			; REGISTERS. 
+	LD	A,(IY+RF_LBA+1)		; BYTE COUNTER
+	INC	C			; IS RESET
 	OUT	(C),A
 	RET
 ;
@@ -318,7 +318,7 @@ RF_CHKWP:
 ;
 ;
 ;
-RF_IO		.DB	0
+RF_IO		.DB	0		; PORT ADDRESS OF ACTIVE DEVICE
 RF_RWFNADR	.DW	0
 ;
 RF_DSKBUF	.DW	0