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Pursuing Tom Ram
Game available in Itch.io. Soruce code in Github. |
Pursuing Tom Ram does not work with any memory expansion. The changes to make it work with a memory expansion are simple.
At the very beginning of the code, you will find the staring address for the code “*=$1001”. VIC-20 unexpanded RAM starts at $1000.
; Starting RAM memory for
;unexpanded VIC-20
*=$1001
You need to change the starting address from $1001 to $401 to run Pursuing Tom Ram with a 3 Kb. memory expansion. For a memory expansion of 8 Kb. or higher, you have to change the starting address from $1001 to $1201.
When you change the RAM starting address, you have to change (or remove) the basic loader too. The original BASIC loader is this:
BYTE $0B, $10, $0A, $00, $9E, $34, $31, $30, $39, $00
BYTE $00, $00
This loader executes a SYS 4109 ($100D), so you have to change the SYS address to the new starting point. For example, if you modify the code for a 3 Kb. expansion, the starting address for SYS is $40D (1037), so the loader will be:
BYTE $0B, $10, $0A, $00, $9E, $31, $30, $33, $37, $00
BYTE $00, $00