Commodore Amiga A500 - 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
DL
= 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: AL
= LINES TO SCROLL (CLEAR WINDOW IF 0)
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
READ CHAR & AITRIBUTE AT CURSOR POSITION (AH = 08H)
INPUT: BH
= ACTIVE DISPLAY PAGE
OUTPUT: AL
= 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: