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Flavioweb
Registered: Nov 2011
Posts: 463 |
Attempt to modify 1541 ROM.
I'm experimenting with some 1541 rom changes using VICE but some strange happen...
I changed just one byte in the rom to avoid rom check:
EB1F: 4C 71 EA JMP $EA71 ; to error display
into
(8:$eb2a) d eb1f
.8:eb1f 2C 71 EA BIT $EA71
it seems i succeeded to load it correctly into Vice.
But:
(8:$eb49) break eb1f
#1 (Stop on exec eb1f)
.8:eb1f 2C 71 EA BIT $EA71 - A:C0 X:C0 Y:00 SP:01 N.-..I.. 813155
(8:$eb1f) z
.8:ea71 A6 6F LDX $6F - A:C0 X:C0 Y:00 SP:01 N.-..I.. 813158
(8:$ea71) z
.8:ea73 9A TXS - A:C0 X:01 Y:00 SP:01 ..-..I.. 813161
(8:$ea73) z
.8:ea74 BA TSX - A:C0 X:01 Y:00 SP:01 ..-..I.. 813163
(8:$ea74) z
.8:ea75 A9 08 LDA #$08 - A:C0 X:01 Y:00 SP:01 ..-..I.. 813165
(8:$ea75) z
.8:ea77 0D 00 1C ORA $1C00 - A:08 X:01 Y:00 SP:01 ..-..I.. 813167
Why?
Where i'm missing the force again =P ? |
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iAN CooG
Registered: May 2002
Posts: 3193 |
erm, are you seriously trying to modify the ROM by editing it with VICE monitor and hoping it will work? |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
Quote: erm, are you seriously trying to modify the ROM by editing it with VICE monitor and hoping it will work?
No, i edited in an external binary editor... then i reloaded it into vice...
But... even if i can see the JMP ($4C) changed to BIT ($2C) correctly using the monitor, the code seems to behave like if the $4C-JMP still here... |
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iAN CooG
Registered: May 2002
Posts: 3193 |
ah ok. I tried the same and it works for me
(C:$e5d4) break 8:eb1f
BREAK: 1 8:$eb1f (Stop on exec)
(8:$eb1f) d
.8:eb1f 2C 71 EA BIT $EA71
.8:eb22 4C 49 FF JMP $FF49
(8:$eb49) z
.8:eb22 4C 49 FF JMP $FF49 - A:C0 X:C0 Y:00 SP:45 N.-..I.. 813159
but I started afresh, relaunching vice and resetting to trigger the breakpoint |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
Here is the file i'm testing:
https://www.dropbox.com/s/je2wattifvvd5js/dos1541-fw?dl=0
I also checked it using "cmp":
cmp -l dos1541 dos1541-fw
11040 114 54 |
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Angel of Death
Registered: Apr 2008
Posts: 211 |
Why don't you use the (well documented) sources made by Soci mentioned in this (Looking for tass sources.) thread? Just change them and assemble them as a raw data-file.
He even rigged the checksum routines to make them bootable when changed. |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
Quote: Why don't you use the (well documented) sources made by Soci mentioned in this (Looking for tass sources.) thread? Just change them and assemble them as a raw data-file.
He even rigged the checksum routines to make them bootable when changed.
Thanks, nice idea =)
Now i managed to make "my rom" work correctly into Vice:
- start vice
- set "no drive" selected
- load my rom
- set drive to 1541
- reset
It work.
Otherwise, don't. |
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iAN CooG
Registered: May 2002
Posts: 3193 |
what do you mean by "Load my ROM"? don't you set it in rom settings? or with -dos1541 parameter? |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
I set it via menu. Load drive rom -> 1541.
But since i'm binary patching, i need from time to time, to load the rom to check what i'm doing.
Loading it directly via menu, without restarting vice and re-setting all drive config, seems don't work. |
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soci
Registered: Sep 2003
Posts: 480 |
My guess is that the 1541-II is set as default and replacing the 1541 ROM makes no difference until you select the 1541 as the drive type. |
