Atari 400 Technical Reference Manual page 152

For controlling applications initialization can also be deferred
until step 7.
Sample Cassette-Boatable Program Listing
Shown below is a skeletal program that can be booted from the
cassette and that retains control when it is entered.
;
THIS IS THE START OF THE PROGRAM FILE.
PST= $0700
(OR SOME OTHER LOCATION).
*=
PST
;
<. ORG)'
THIS IS THE cassette-boot CONTROL INFORMATION.
· BYTE
0
(DOESN'T MATTER).
· BYTE
PND-PST+127/128 NUMBER OF RECORDS.
· WORD
PST
MEMORY ADDRESS TO START LOAD.
· WORD
PINIT
PROGRAM INIT.
THIS IS THE START OF THE BOOT CONTINUATION.
LDA 1$3C STOP THE CASSETTE.
STA PACTL
LDA IPND ESTABLISH LOW MEMORY LIMITS.
STA MEMLO
STA APPMHI
LDA IPND/256
STA MEMLO+l
STA
APPMHI+l
LDA IRESTRT ESTABLISH RESTART VECTOR.
STA DOSVEC
LDA IRESTRT/256
STA DOSVEC+l
CLC
i
SET FLAG FOR SUCCESSFUL BOOT.
RTS
APPLICATION INITIALIZATION ENTRY POINT.
PINIT RTS
; NOTHING TO DO HERE FOR ...
; ... CONTROLLING APPLICATION.
i
THE MAIN BODY OF THE PROGRAM FOLLOWS.
RESTRT=*
; THE MAIN BODY OF THE PROGRAM ENDS HERE.
OPERATING SYSTEM C016555 -- Section 10
167