home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Apple II Magazines (PO)
/
Nibble Volume 10, No. 07 (1989-07)(MindCraft Publishing)(Side A).zip
/
Nibble Volume 10, No. 07 (1989-07)(MindCraft Publishing)(Side A).po
/
OVERLAY.BIN.S
< prev
next >
Wrap
Text File
|
1996-12-24
|
2KB
|
56 lines
******************************
* OVRLY 11/13/88 *
* COPYRIGHT 1988 *
* BY E. L. CRANFORD, JR. *
* ST. PETERSBURG, FL *
******************************
START = $300
ORG START
CHRGET = $B1
CHKCOM = $DEBE
FNDLIN = $D61A
LOWTR = $9B
LINGET = $DA0C
TEXTTAB = $67
TEXTTMP = $1E
STORE = $A8
RECALL = $A7
*-------------------------------
LDA #EVAL ;Set & vector.
STA $3F6
LDA #>EVAL
STA $3F7
RTS
*-------------------------------
EVAL PHA ;Save token.
JSR CHRGET ;Advance TXTPNTR.
PLA ;Recover token.
CMP #STORE
BEQ MOVSTART
CMP #RECALL
BEQ RESET
RTS ;Missed.
*---------------------------
MOVSTART LDA TEXTTAB ;Save original program
STA TEXTTMP ;start pointer.
LDA TEXTTAB+1
STA TEXTTMP+1
JSR CHKCOM ;Check for a comma
JSR LINGET ;Find the line which will
JSR FNDLIN ;be the last line in the
LDY #0 ;main program.
LDA (LOWTR),Y ;Find the location for the
STA TEXTTAB ;beginning of the overlay
INY
LDA (LOWTR),Y ;and set program start
STA TEXTTAB+1 ;pointer.
RTS
*-------------------------------
RESET LDA TEXTTMP ;Reset program start to
STA TEXTTAB ;original location.
LDA TEXTTMP+1
STA TEXTTAB+1
RTS
*-------------------------------