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Old 03 January 2015, 10:09   #4
Toni Wilen
WinUAE developer
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 42
Posts: 20,496
Originally Posted by mark_k View Post
I seem to remember reading somewhere that 4.13 was the last version actually shipped by GVP.

The SCSI controller on GVP accelerators can DMA to all RAM, there's no 24-bit restriction. I assume the current GVP hardware emulation can only do 24-bit DMA? It's possible there could be Mask issues if using an image from a real Amiga with GVP accelerator SCSI. Or maybe the GVP ROM checks the product ID and knows to only DMA to 24-bit addresses even if Mask=0xFFFFFFFE for example.
Current emulation emulates Z2 board version of GVP which can only do 24-bit.

According to NetBSD gvp drivers some accelerators with built-in SCSI have only 24bit or 25bit DMA support. (sys/arch/amiga/dev/gvpbus.c and gtsc.c)

I am quite sure driver will detect hardware model, for example Z2 GVP with RAM outside of 24-bit space: DMA is always done to buffer in 24-bit fast or chip ram.
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