; Emulated 65C02 SOC
;
; By Daryl Rictor (c)2012
;
; 16k - 256 byte RAM
; 48k ROM (in flash)
; IO @ 3Fxx

;******************************************************************************
; include AVRASM definitions
;******************************************************************************
.include "m1284Pdef.inc"

;******************************************************************************
; Set Register definitions
;******************************************************************************
.def  i		= R16
.def  j		= R17
.def  zero	= R2
.def  one	= R3
.def  mmap  = R4

.def  free1 = R12				; unused register pair
.def  free2 = R13

;******************************************************************************
; Load Lower Flash Tables starting at 0x1B00 (below ROM image)
;******************************************************************************

.include	"av2sr.inc"
.include	"sr2av.inc"
.include	"opcjmp.inc"
.include	"ioexe.inc"
.include	"sbcrom.inc"


;******************************************************************************
; Program Starts here on Reset
;******************************************************************************
STARTUP:						; first line executed after reset 
	CLI							; disable interupts

;******************************************************************************
; Initialize the I/O Ports
;******************************************************************************
; port A pins 
	ldi		i, 0xff				; 
	out		porta, i			; 
	LDI		i, 0x00				; 
	out		ddra, i				; 

; port B pins 
	LDI		i, 0xff				; 
	out		portb, i			; 
	LDI		i, 0x00				; 
	out		ddrb, i				; 

; port C pins 
	ldi		i, 0xff				; 
	out		portc, i			; 
	LDI		i, 0x00				; 
	out		ddrc, i				; 

; port D pins
	ldi		i, 0xff				;
	out		portd, i			;
	LDI		i, 0x00				;
	out		ddrd, i				;

;******************************************************************************
; Init other CPU I/O registers
;******************************************************************************
	ldi		i, 0x80
	out		ACSR, i				; turn off comparator

	ldi		i, 0x40				; set stack pointer to top of SRAM 
	out		SPH, i				;
	ldi		i, 0xff				; 
	out		SPL, i				;

;******************************************************************************
; Init RS-232 port
;******************************************************************************
InitRS232:
	; set baud rate
	ldi		i, 0x0C				; 
								; 			16MHZ	20MHZ	24MHz
	ldi		j, 0x00				; 115200	xxxx	000A	000C
	sts		UBRR0H, j			;  19200	0033	0040	004D
	sts		UBRR0L, i			;  9600		0067	0081	009B
								;  4800		00CF	0103	0137
;								;  2400		019F 	0208	0270


	; Enable receiver and transmitter
	ldi		i, (1<<RXEN0)|(1<<TXEN0)
	sts		UCSR0B, i
	
	; Set frame format: 8data, 1stop bit
	ldi		i, (3<<UCSZ00)
	sts		UCSR0C, i

;******************************************************************************
; Init program registers
;******************************************************************************
	clr		zero
	ldi		i, 0x01
	mov		one, i
	ldi		i, 0x3F			; IO Page
	mov 	mmap, i

;******************************************************************************
; Show Engine version
;******************************************************************************
	ldi		zl, low(version*2)
	ldi		zh, high(version*2)
	out		rampz, one
ver1:
	elpm	i, Z+
	tst		i
	breq	Ready
	call	Put_Chr
	rjmp	ver1	

;******************************************************************************
; Main Loop
;******************************************************************************
Ready:
	out		rampz, zero
	call	CPU_RESET
	jmp		Main		; Enter CPU Execute Loop

;***********************
; Version #
;***********************
version: .db 0x0d,0x0a,"Version 3.1 - Starting Emulator... ", 0x0d, 0x0a, 0x00

;******************************************************************************
; include CPU emulator and bootloader files (after ROM image)
;******************************************************************************
; these files in the application area

.include	"cpu.asm"

; These files are in the Bootloader section
.include	"bootload.asm"
.include	"xmodem-receive.asm"
;
; $0000-$3EFF - 15.75k RAM
; $3F00-$3FFF - I/O
; $4000-$FFFF - 48k ROM 
;
; Version 2.7 supports AVR interrupts and the full AVR IO page access
; 	      FULL WDC 65C02 instruction set, including BCD mode
; V 3.0 changed opcode excution to a macro and added a table for IO execute
;       also moved IRQ flag from GPIOR0 ro R5 - EEPROM flag moved to GPIOR0
;	fixed NOP byte count for unused opcoded
;	updated bootloader to load engine across the $8000 word boundary
; Version 3.1 - corrected opcode behavior