;---------------------------------------------------------------------------
; simple example that demonstrates how to write to the flash ROM
; 
; this test programs first page of each 8k bank and writes a single value 
; that represents the bank number to the first (low byte) and second (high byte)
; bank
;---------------------------------------------------------------------------

        !src "../include/gmod3.inc"

        * = $0801
        !word nextline
        !word 2016 
        !byte $9e
        !byte $32, $30, $36, $31
nextline:
        !byte 0,0,0
        jmp start
        
        !src "../lib/gmod3.asm"
        
NOHIGHBYTE = 0        

;-------------------------------------------------------------------------------        

start:
        ;sei

        ; clear screen
        ldx #0
-
        lda #$20
        sta $0400,x
        sta $0500,x
        sta $0600,x
        sta $0700,x
        lda #$01
        sta $d800,x
        sta $d900,x
        sta $da00,x
        sta $db00,x
        inx
        bne -


        ldy #0
--
        tya
        pha
        
        !if NOHIGHBYTE = 0 {
        sta cart_file_start+1
        }

        ldx #0
-
        
        txa
        pha

        sta cart_file_start
        
        inc $0420   ; to indicate progress

        ; erase 64k page if needed
        lda pagelo
        bne +       ; only erase when lobyte is 0, ie every 64k
        lda pagehi
        jsr flash_erase
+
        inc $0421   ; to indicate progress
        
        ; set byte program command and flash address
pagehi=*+1
        lda #0
        sta addr2
pagelo=*+1
        lda #0
        sta addr1
        ;lda #0
        ;sta addr0

        inc $0422   ; to indicate progress
        
        lda #<cart_file_start
        ldx #>cart_file_start
        ; program one 256byte page
        jsr flash_writepage

        lda cart_file_start
        pha
        lsr
        lsr
        lsr
        lsr
        tay
        lda hexdigits,y
        sta $0400
        pla
        and #$0f
        tay
        lda hexdigits,y
        sta $0401        
        
        lda cart_file_start+1
        pha
        lsr
        lsr
        lsr
        lsr
        tay
        lda hexdigits,y
        sta $0402
        pla
        and #$0f
        tay
        lda hexdigits,y
        sta $0403        
        
        lda pagehi
        pha
        lsr
        lsr
        lsr
        lsr
        tay
        lda hexdigits,y
        sta $0405
        pla
        and #$0f
        tay
        lda hexdigits,y
        sta $0406        
        
        lda pagelo
        pha
        lsr
        lsr
        lsr
        lsr
        tay
        lda hexdigits,y
        sta $0407
        pla
        and #$0f
        tay
        lda hexdigits,y
        sta $0408
        
        lda pagelo
        clc
        adc #$20
        sta pagelo
        bcc +
        inc pagehi
+
        
        pla
        tax

        inx
        beq +
        jmp -
+

        pla
        tay
        
        iny
        cpy #$08
        beq + 
        jmp --
+

-
        inc $d020
        dec $d020
        jmp -

failure:
        lda #2
        sta $d020
        jmp *

hexdigits:
        !scr "0123456789abcdef"
    
;-------------------------------------------------------------------------------
; align to page boundary so we only have to compare the highbyte of the
; source address in the above loop
        !align 255,0
cart_file_start:
        !for i,0,255 {
        !byte $ff
        }