Why can't $01 be changed as shown

JMP $FCE2
jrubin
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Location: Florida

Why can't $01 be changed as shown

Post by jrubin » Sun Nov 16, 2014 12:20 am

a 033c lda #$36
sta $01
brk

g 033c


checking address 0001 will still show 37? why?


J



dudz
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Re: Why can't $01 be changed as shown

Post by dudz » Sun Nov 16, 2014 10:33 am

probably the monitor program you are using sets it to whatever it needs when the brk was hit

jrubin
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Re: Why can't $01 be changed as shown

Post by jrubin » Sun Nov 16, 2014 6:57 pm

TFC3


I can poke the values in basic..... this must be a tfc3 limitation

satpro

Re: Why can't $01 be changed as shown

Post by satpro » Mon Nov 17, 2014 12:58 pm

Jordan,
dudz is right: it's definitely the monitor. Actually, the bank-switching cartridges are normally this way so that when you are accessing memory it's from the computer's main memory default, which is $37 at address $01.

From The Final Cartridge III manual:
BANK SWITCHING [12.3.5]
Your Commodore is provided with several ROMS. Using the bank switch command, the letter O, you can turn the ROMs on and off. This is called bank switching because you switch between several banks of memory. In the register display you can see what bank you're in at that moment. For more details you should read the explanation of the O command.

MODES [12.3.6]
If you have a disk-drive, you can work with two kinds of memory: the memory of your computer, and the memory of the disk-drive. That's why there are two modes: the computer-mode (mode 1), and the disk-mode (mode 2).

SWITCHING BETWEEN MODES
The monitor automatically switches to mode 1. All commands that work with memory use the memory of the computer. You can recognize this mode because in the register display the current bank is displayed. To switch to the memory of the disk, you use the OD command. All commands that work with memory, now use the memory of the disk-drive. You can recognize the disk-mode because in the register display the letters DS indicate the selected bank. To return to the computer mode, you can use the O command (or O followed by the number of the bank you want to work in).

This behavior can be annoying until you get the hang of it, but it's a small price to pay for the power it brings. If you need the manual just click here --> http://ar.c64.org/rrwiki/images/7/70/Fi ... Manual.pdf

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