IBM PC CONVERTIBLE Technical Reference page 141

OA5B E9 016F R JMP VIDEO_RETURN
OA5E PHYS_DSP _DESCR_REQ ENDP
Print Screen Interrupt Hex 05
(PRT_SCRN)
OA5E
OA5E FB
OA5F 06
SUBTTL PRINT SCREEN BIOS INT 05H HANDLER
; *********************************************************************
ROUTINE-NAME: PRLSCRN
FUNCTION: THIS ROUTINE PRINTS THE SCREEN
ENTRY CONDITIONS:
PURPOSE OF ENTRY: PRINT SCREEN
INPUT CONDITIONS: NONE
RESTRICTIONS: ONLY ONE PRINT SCREEN REQUEST AT A TIME
EXIT CONDITIONS:
NORMAL EXIT CONDITIONS:
STATUS_BYTE (50:0) " 0
THE SCREEN IS PRINTED OR IF CTRc BREAK IS
PRESSED THE PRINT IS TERMINATED.
ERROR EXIT CONDITIONS:
STATUS_BYTE (50:0) "OFFH (PRINTER ERROR)
THE PRINT IS TERMINATED.
STATUS_BYTE (50:0) "01 (PRINT SCREEN IN PROG.)
PRINT SCREEN IS ALREADY IN PROGRESS AND ANOTHER
PRINT SCREEN IS REQUESTED THE LATEST PRINT
SCREEN REQUEST IS IGNORED.
REGISTERS MODIFIED: ALL SAVED
RETURN TYPE: IRET (ALL FLAGS RESTORED)
INTERRUPTS: ENABL ED OUR I NG PROCESSI NG
INTERNALLY REFERENCED ROUTINES: CRLF
EXTERNALLY REFERENCED ROUTINES: INT 10H (VIDEOJN)
INT 17H (PRINTER_FN)
; ******************************************************************************
I NT 5H - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - -- - - -- - - - --
THIS LOGIC WILL BE INVOKED BY INTERRUPT 05H TO PRINT THE
SCREEN. CURSOR POSITION AT THE TIME THIS ROUTINE IS INVOKED
WILL BE SAVED AND RESTORED UPON COMPLETION. THE ROUTINE IS
INTENDED TO RUN WITH INTERRUPTS ENABLED. I F A SUBSEQUENT
'PRINT SCREEN' KEY IS DEPRESSED DURING THE TIME THIS ROUTINE
IS PRINTING IT WILL BE IGNORED.
IF THE CONTROL BREAK KEYS ARE PRESSED DURING THE PRINTING, THE
PRINT SCREEN REQUEST IS TERMINATED.
ERRORS ENCOUNTERED DURING PRINT (RETURN BY INT 17H) CAN BE
OUT OF PAPER, I/O ERROR AND TIME OUT.
STATUS BYTE IS UPDATED ON EACH CALL TO PRINT SCREEN.
ADDRESS 50:0 CONTAINS THE STATUS OF THE PRINT SCREEN:
50: 0 "0
"1
"255
EITHER PRINT SCREEN HAS NOT BEEN CALLED
OR UPON RETURN FROM A CALL THIS INDICATES
A SUCCESSFUL OPERATION.
PRINT SCREEN IS IN PROGRESS
ERROR ENCOUNTERED DURING PRINTING
ASSUME CS: ROMCODE, OS: DATA, ES: XXDATA
PRLSCRN PROC FAR
STI
PUSH ES
MUST RUN WITH INTERRUPTS ENABLED
MUST USE 50:0 FOR DATA AREA
2-116 ROM BIOS