Source of a small tool that allows to edit several screens at basic-prompt.
Tried to keep it small.
load it, NEW and SYS 828
F1/F7 select between 26 screens which are all stored in georam. (you start at screen 'C')
F5/F3 are copy/paste for screen.
Code in tapebuffer.
Enjoy if you can :) /enthusi

 
!to "geoutil"

bankblk  = $dfff ;00-31($1f) / 16kb
bankpag  = $dffe ;00-63      /256b
bankadr  = $de00 ;-$deff
srclo    = $ae
srchi    = $af
dir 	 = $fc
blknow   = $fd
pagnow   = $fb

;---------------------------------------
         *= $033c
init
         sei
         lda #<irq
         sta $0314
         lda #>irq
         sta $0315
	 sta blknow	;thus we start at blk 3 :o) 2 bytes saved
         cli
         rts
;---------------------------------------
irq
         sei 		; could be saved as well
         lda #$fe
         sta $dc00
         lda $dc01
         cmp #$ef
         beq f1
	 cmp #$f7
         beq f7
	 cmp #$df
	 beq f3    ;fend ;= f3 = read + ea31
	 cmp #$bf
	 beq f5
        
irqend
         jmp $ea31
;---------------------------------------
f3	 ;read from buffer

	 lda blknow
	 pha
	 ldx #$1e
	 stx blknow
	 jsr read
	 ;jmp ret
	 
ret	;from f3/f5 (moved it here, was a call first (saved 3 bytes))
	 pla
	 sta blknow
	 jmp $ea31

f5	 ;write to buffer
         lda blknow
	 pha
	 ldx #$1e
	 stx blknow
	 jsr write
	 jmp ret
f1
         jsr write
         dec blknow
         bne fend; f1b	//evil change now does a full write to inc blknow :)
         ;inc blknow
f1b
         ;jmp fend
f7
         jsr write
         ldx blknow
         cpx #$1a
         beq fend
         inc blknow

fend     jsr read
	 jmp $ea31
;---------------------------------------
read     
	 lsr dir
	 ;dec dir
         jsr trans
	 ;here was a jsr initcurs - just moved the function in
	 ;and saved a jsr XX + rts = 4 bytes
initcurs
	 ldy $d3	; current cur-row
	 lda ($d1),y	; position
	 and #$7f	; un-invert
	 sta ($d1),y	; store again
	 sta $ce	; store as char beneath cursor
	 lsr $cf; = set to 0	= char not inverted atm

         rts		; jump here would safe one byte
;---------------------------------------
write	
         lda #$01	;cant inc - might occur twice
         sta dir
	 jsr initcurs
         ;jsr trans	;just moved it here - yay! 4 bytes saved
         ;rts
;---------------------------------------
trans
         lda blknow   ;set actual block
         sta bankblk
	 sta $0427

transi	 lda #$00     ;set src, grouped together
         sta srclo
         sta bankpag  ;init page
         sta pagnow
    
	 tay	;instead of ldy #$00
	
	 lda #$04
         sta srchi
	 
tran0    ;ldy #$00

tran1    ldx dir
         beq g2s

s2g      lda (srclo),y ;screen->georam
         sta bankadr,y
         jmp next

g2s      lda bankadr,y ;georam->screen
         sta (srclo),y

next     iny
         bne tran1
         inc srchi
         lda srchi
         cmp #$08
         beq tranend
         inc pagnow
         ldx pagnow
         stx bankpag	;beware! cant read bankpag (no inc, etc)
         jmp tran1

tranend  rts