Commodore Amiga A500 Technical Reference Manual page 128

READ LIGHT PEN
(AH
=
04H)
INPUT: None
OUTPUT: AH
=
0 if light pen not triggered. 1 if it is
DH
=
Character row of light pen
D L
=
Character column of light pen
CH
=
Pixel row
BX
=
Pixel column, best estimate
SELECT ACTIVE DISPLAY PAGE (AH
=
05H)
INPUT: AL
=
NEW ACTIVE DISPLAY PAGE
OUTPUT: AX
=
(?)
SCROLL ACTIVE PAGE UP
(AH
=
06H)
INPUT:
AL =LlNESTOSCROLL(CLEARWlNDOWIFO)
BH
=
ATTRIBUTE FOR BLANK LINE(S)
CH, CL
=
ROWICOLUMN OF UPPER LEFT
CORNER OF WINDOW
DH, DL
=
ROWICOLUMN OF LOWER RIGHT
CORNER OF WINDOW
OUTPUT: None
SCROLL ACTIVE PAGE DOWN
(AH
=
07H)
INPUT: A L
=
LINES TO SCROLL (CLEAR WINDOW IF 0)
BH
=
ATTRIBUTE FOR BLANK LINE(S)
CH. CL
=
ROWICOLUMN OF UPPER LEFT
CORNER OF WINDOW
DH, D L
=
ROWICOLUMN OF LOWER RIGHT
CORNER OF WINDOW
OUTPUT: None
READ CHAR & AITRIBUTE AT CURSOR POSITION
(AH
=
08H)
INPUT: BH
=
ACTIVE DISPLAY PAGE
OUTPUT: A L
=
CHARACTER
AH =ATTRIBUTE
(not defined for graphics, however we return
an ORing of any and all color bits set
as
the
attribute, a reasonable compromise)
GRAPHICS MODE READ: