Force non-zero VBR for testing

hop · 22 June 2022, 14:27

I'd like to test my system shutdown/restore code works with 68010+ processors with non-zero VBR.

Under what configurations does non-zero VBR occur? Would it occur on stock A1200 or only with extra hardware added or if the OS is running a VM?

Is there a convenient way of getting the system into a legitimate non-zero VBR state for testing (in WinUAE)?

Thanks for any insight.

mcgeezer · 22 June 2022, 15:26

You can use the vbrmove tool for this and it will move it.

http://aminet.net/package/util/boot/vbrmov23

Pretty sure its that one I used.

a/b · 22 June 2022, 15:43

setpatch (e.g. in startup-sequence), or any additional cpu libraries (typically for 040/060) will move it to fast ram if available, otherwise it remains at zero as far as I know.
To mess with vbr and icache/dcache I use cpucontrol (should be on aminet).

Thomas Richter · 22 June 2022, 17:45

Not by default, or at least not mine. The issue is that some programs react allergic if the VBR is moved. But you can do so by MuFastZero:

Code:

MuFastZero MoveVBR

nogginthenog · 22 June 2022, 17:47

Sometimes the vector table (first 4K or so?) is mapped into fast ram by the MMU and VBR remains zero.

hop · 22 June 2022, 20:34

Thanks. I'll try these out. I have always wondered what setpatch does!

22 June 2022, 14:27	#1
hop Registered User Join Date: Apr 2019 Location: UK Posts: 249	Force non-zero VBR for testing I'd like to test my system shutdown/restore code works with 68010+ processors with non-zero VBR. Under what configurations does non-zero VBR occur? Would it occur on stock A1200 or only with extra hardware added or if the OS is running a VM? Is there a convenient way of getting the system into a legitimate non-zero VBR state for testing (in WinUAE)? Thanks for any insight.

22 June 2022, 17:45	#4
Thomas Richter Registered User Join Date: Jan 2019 Location: Germany Posts: 3,315	Not by default, or at least not mine. The issue is that some programs react allergic if the VBR is moved. But you can do so by MuFastZero: Code: MuFastZero MoveVBR

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22 June 2022, 15:26	#2
mcgeezer Registered User Join Date: Oct 2017 Location: Sunderland, England Posts: 2,702	You can use the vbrmove tool for this and it will move it. http://aminet.net/package/util/boot/vbrmov23 Pretty sure its that one I used.

22 June 2022, 15:43	#3
a/b Registered User Join Date: Jun 2016 Location: europe Posts: 1,065	setpatch (e.g. in startup-sequence), or any additional cpu libraries (typically for 040/060) will move it to fast ram if available, otherwise it remains at zero as far as I know. To mess with vbr and icache/dcache I use cpucontrol (should be on aminet).

22 June 2022, 17:47	#5
nogginthenog Amigan Join Date: Feb 2012 Location: London Posts: 1,317	Sometimes the vector table (first 4K or so?) is mapped into fast ram by the MMU and VBR remains zero.

22 June 2022, 20:34	#6
hop Registered User Join Date: Apr 2019 Location: UK Posts: 249	Thanks. I'll try these out. I have always wondered what setpatch does!

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