Atari DOS 2.5: XF551 Owner's Manual page 59

(HIGH) Hex. The INIT address is always stored in Locations 2E2
(LOW) and 2E3 (HIGH) Hex. Remember, the INIT address is exe-
cuted as soon as it is loaded , so the code that it points to must
have been previously loaded .
Note: lOCB #1 is open during the execution of code pointed to
by any INIT address. For this reason it is not available and must
not be tampered with by the user program being executed .
Using Binary Save With Optional Parameters
The example below ill ustrates an assembly language program
that uses a data area that must be initialized before the main
program can use it . Suppose the initialization code resides from
address 4000 (Hex) to 41 FF (Hex) and the main program resides
between 4200 (Hex) and 4FFF (Hex). For purposes of illustration ,
assume that both the initialization code and main program can ·
tain executable code and the initialization code ends with an RTS
(RETUR N).
In the following example , it is assumed that the program
LAGP RG.OBJ is already in memory.
Example 2:
SELECT ITEM OF: ["""" [ FOP I1EI1U
K ["""" I
SAUE-GIUEFILE,STAPT,END ( ,INIT,F:UN)
LAGPRG . OBJ, 400(1, 4FFF, 4000, 4200j Aew-n 1
The following events will occur on loading t his file into memory:
1. Memory from 4000 to 4FFF will be filled with the program .
2. The INIT address 4000 (Hex) is stored in Memory Locations
2E2 and 2E3 (Hex).
3. Initialization program from 4000 to 41 FF will execute.
4. The RU N address 4200 (Hex) is stored in Memory Locations
2EO and 2El (Hex).
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