[Fceultra-discuss] [ fceultra-Bugs-2108524 ] Lua doesn't recognize frozen addresses

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Bugs item #2108524, was opened at 2008-09-13 01:34
Message generated for change (Comment added) made by adelikat
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https://sourceforge.net/tracker/?func=detail&atid=113536&aid=2108524&group_id=13536

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Category: lua
Group: None
Status: Open
Resolution: None
Priority: 8
Private: No
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: Lua doesn't recognize frozen addresses

Initial Comment:
Middle-clicking in the Hex Editor, selecting Freeze, or adding it to the Cheats window manually will cause memory addresses to behave oddly. They don't "freeze"; an Lua script that simply displays the state of the RAM address will act strangely and display the wrong value.

22:27'01" Sonicandtails: i froze 0x075A
22:27'03" Sonicandtails: at 02
22:27'40" Sonicandtails: The Lua counter starts at x3
22:27'49" Sonicandtails: Drops to x2 when you die even if the life counter is frozen in RAM
22:27'55" Sonicandtails: Then stays at x2

Tested using 4matsy's SMB Lua and the latest FCEUX.
Lua script is attached for easy access

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>Comment By: Andres Delikat (adelikat)
Date: 2009-02-23 12:39

Message:
Here are the factors in this:
1) Lua's memory read.byte will only update when the memory address changes
by the game (adding a cheat that changes its value will not update it.  I
don't necessarily think this is an issue).
2) When freezing in Hex editor, it allows the value to change once, but
still display the original value.  For instance, if you freeze mario's
lives at 1 and die, Lua will receive that the value changed to 0.  Memory
watch, hex editor, and cheats still show it at 1.  However, as soon as you
unfreeze, it goes down to 0.  

If you die twice and then go to unfreeze, it still moves down to 0.  So
somehow hex editor allows the value to change once.  

Adding a cheat via the cheat search window will do this too.  Make a cheat
that turn his lives to 10 and it will immediately change to 10.  Turn off
the cheat and it will go back to 2.  Turn the 10 lives cheat on and die,
then turn if off: 9 Lives.

So the game is keeping track of the "real value" and even allows it to
change once before truly freezing.  Lua is seeing the "real" value, which
is why are you getting the results that you are.

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Comment By: Andres Delikat (adelikat)
Date: 2009-02-23 12:30

Message:
Here are the factors in this:
1) Lua's memory read.byte will only update when the memory address changes
by the game (adding a cheat that changes its value will not update it.  I
don't necessarily think this is an issue).
2) When freezing in Hex editor, it allows the value to change once, but
still display the original value.  For instance, if you freeze mario's
lives at 1 and die, Lua will receive that the value changed to 0.  Memory
watch, hex editor, and cheats still show it at 1.  However, as soon as you
unfreeze, it goes down to 0.  

If you die twice and then go to unfreeze, it still moves down to 0.  So
somehow hex editor allows the value to change once.  

Adding a cheat via the cheat search window will do this too.  Make a cheat
that turn his lives to 10 and it will immediately change to 10.  Turn off
the cheat and it will go back to 2.  Turn the 10 lives cheat on and die,
then turn if off: 9 Lives.

So the game is keeping track of the "real value" and even allows it to
change once before truly freezing.  Lua is seeing the "real" value, which
is why are you getting the results that you are.

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Comment By: Andres Delikat (adelikat)
Date: 2009-02-23 11:18

Message:
Here are the factors in this:
1) Lua's memory read.byte will only update when the memory address changes
by the game (adding a cheat that changes its value will not update it.  I
don't necessarily think this is an issue).
2) When freezing in Hex editor, it allows the value to change once, but
still display the original value.  For instance, if you freeze mario's
lives at 1 and die, Lua will receive that the value changed to 0.  Memory
watch, hex editor, and cheats still show it at 1.  However, as soon as you
unfreeze, it goes down to 0.  

If you die twice and then go to unfreeze, it still moves down to 0.  So
somehow hex editor allows the value to change once.  

Adding a cheat via the cheat search window will do this too.  Make a cheat
that turn his lives to 10 and it will immediately change to 10.  Turn off
the cheat and it will go back to 2.  Turn the 10 lives cheat on and die,
then turn if off: 9 Lives.

So the game is keeping track of the "real value" and even allows it to
change once before truly freezing.  Lua is seeing the "real" value, which
is why are you getting the results that you are.

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Comment By: Andres Delikat (adelikat)
Date: 2009-02-23 11:02

Message:
Ok, so this issue is definately with the hex editor.  If you freeze the
address with the cheats window, everything works out fine.

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Comment By: Andres Delikat (adelikat)
Date: 2008-12-14 16:50

Message:
Freezing works just fine in this case.  What is happening is that Lua
doesn't recognize and read frozen addresses.  This was done
semi-intentionally when Lua was designed.  If you watch an address in the
hex editor or memory watch you see it is behaving normally.

Lua may need to be changed to recognize frozen addresses so I am changing
the name of this bug issue and adding it to the Lua category.

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Comment By: qFox (qfox)
Date: 2008-12-12 20:26

Message:
The problem is the secret (1k?) limit on addresses that can be frozen at
once. A fix is not anywhere to be seen for now...

-- qFox, who doesnt feel like logging in.

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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=113536&aid=2108524&group_id=13536