AppleIIAsm-Collection/disks/disk2_common/T.REQUIRED.VARS
nathanriggs 12a0b19398 Disk 2 COMMON library 0.3.0 updates
- added some error control
- added initial jump table
- fixed a few minor bugs
- separated common library into separate subroutine files
2019-01-14 10:57:05 -05:00

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*
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* *
* VARIABLES AND SETTINGS *
* *
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*
* VARIABLE DECLARATIONS ********
*
** JUMP TABLE SETUP. THIS IS FOR LOADING
** SUBROUTINES INTO MEMORY FOR ACCESS BY
** EXTERNAL EXECUTIONS. NOTE THAT THIS
** SHOULD ALWAYS BE THE VERY FIRST BIT OF
** CODE IN THE PROGRAM SO THAT ITS
** LOCATION IN MEMORY IS EASILY KNOWN.
*
JUMPTBL JMP MAIN_START ; ** ALWAYS ** START WITH
; JUMP TO MAIN_START
DS 60 ; 20 MORE ENTRIES
*
** 256 BYTES DEDICATED TO RETURN
** VALUES OF VARIABLE LENGTH; CAN BE
** MODIFIED TO SUIT SMALLER OR LARGER
** NEEDS.
*
RETLEN DS 1 ; RETURN VALUE BYTE LENGTH
RETURN DS 256
*
** 256 BYTE VALUE DEDICATED TO LARGE
** OR VARIABLE LENGTH PARAMETERS. THIS
** CAN ALSO BE CHANGED TO FIT SMALLER OR
** LARGER BOUNDS.
*
PARLEN DS 1
PARAM DS 256
*
** ERROR HANDLING
*
ERRSTOP DS 1
ERRCTRL DS 1
ERRA DS 1
ERRX DS 1
ERRY DS 1
ERRCARRY DS 1
ERRNEG DS 1
ERRZERO DS 1
ERROVF DS 1
*
* SETTINGS *********************
*
MAIN_START
*
** ERROR HANDLING
*
** SET ERRSTOP TO 1 IF YOU WANT THE PROGRAM TO
** HALT WHEN AN ERROR IS CAUGHT
*
LDA #1
STA ERRSTOP
*
** SET ERRCTRL TO 1 IF YOU WANT ERROR CATCHING ON
** IN THE FIRST PLACE. HAVING THIS TURNED OFF WILL
** SAVE A FEW CYCLES, BUT POSSIBLY AT THE EXPENSE
** OF YOUR FRUSTRATION. CAN BE TURNED ON LATER THOUGH.
*
LDA #1
STA ERRCTRL
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