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https://opencores.org/ocsvn/rtftextcontroller/rtftextcontroller/trunk
Subversion Repositories rtftextcontroller
[/] [rtftextcontroller/] [trunk/] [software/] [rtfTextControllerSampleUsageCode.x68] - Rev 26
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;------------------------------------------------------------------------------
; Code Sample from system bios ROM.
;------------------------------------------------------------------------------
TEXTSCR EQU 0xFFD00000
COLORSCR EQU 0xFFD10000
TEXTCTRL EQU 0xFFDA0000
TEXT_COLS EQU 0xFFDA0000
TEXT_ROWS EQU 0xFFDA0002
TEXT_CURPOS EQU 0xFFDA0016
;------------------------------------------------------------------------------
; Clear the screen and the screen color memory
; We clear the screen to give a visual indication that the system
; is working at all.
;------------------------------------------------------------------------------
;
ClearScreen:
move.w TEXT_COLS,d1 ; calc number to clear
mulu.w TEXT_ROWS,d1
move.w #32,d0 ; space character
move.l #TEXTSCR,a0 ; text screen address
csj4:
move.w d0,(a0)+
dbeq d1,csj4
move.w TEXT_COLS,d1 ; calc number to clear
mulu.w TEXT_ROWS,d1
move.w ScreenColor,d0 ; a nice color blue, light blue
move.l #COLORSCR,a0 ; text color address
csj3:
move.w d0,(a0)+
dbeq d1,csj3
rts
;------------------------------------------------------------------------------
; Scroll text on the screen upwards
;------------------------------------------------------------------------------
;
ScrollUp:
movem.l d0/d1/d2/a0,-(a7)
move.w TEXT_COLS,d0 ; calc number of chars to scroll
mulu.w TEXT_ROWS,d0
sub.w TEXT_COLS,d0 ; one less row
lea TEXTSCR,a0
move.w TEXT_COLS,d2
asl.w #1,d2
scrup1:
move.w (a0,d2.w),(a0)+
dbeq d0,scrup1
move.w TEXT_ROWS,d1
subi.w #1,d1
jsr BlankLine
movem.l (a7)+,d0/d1/d2/a0
rts
;------------------------------------------------------------------------------
; Blank out a line on the display
; line number to blank is in D1.W
;------------------------------------------------------------------------------
;
BlankLine:
movem.l d0/a0,-(a7)
move.w TEXT_COLS,d0
mulu.w d1,d0 ; d0 = row * cols
asl.w #1,d0 ; *2 for moving words, not bytes
add.l #TEXTSCR,d0 ; add in screen base
move.l d0,a0
move.w TEXT_COLS,d0 ; d0 = number of chars to blank out
blnkln1:
move.w #' ',(a0)+
dbeq d0,blnkln1
movem.l (a7)+,d0/a0
rts
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