Zeropage compatibility of 1541IDE

ruud.baltissen_at_apg.nl
Date: 2008-03-11 08:59:05

Hallo allemaal,
 
 
So far all used memory variables, with the exeption of one, remain on
their original place in memory as declared by the 1541. The exeption is
SAVSP, a temporary storage for the Stack Pointer. I needed four bytes in
a row and SAVSP was in the middle of a nice range. As this is a variable
that is of no use to a user, I decided to move it.
 
For the LBA filesystem I need more successive zeropage addresses. The
question is: how far can I go by moving existing variables? Quite
obvious the addresses I should not move are the ones users use to change
the device address. But these are the only ones that come in my mind. 
 
Are there more addresses I should keep my hands off? Thanks!
 

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