| Re: [hatari-devel] VME access |
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Hi,
On 1/3/21 2:33 PM, Christian Zietz wrote:
Eero Tamminen schrieb:
As Thorsten mentioned, all that would be useless
until some actual VME HW is also emulated.
That is not strictly true. The SCU (or its future emulation) also
handles interrupt routing for on-board interrupts. I.e., you can mask
interrupts (such as for example the MFP) and you can even raise
interrupts by writing to SCU registers. This is probably rarely used,
but it is not correct that the SCU is only required when emulating VME
bus cards.
It would be MegaSTE/TT specific, and such SW is
rare to start with, so something using SCU without
VME cards would be even rarer.
Does anybody know any SW doing that?
Thomas, it's about interrupt handling and based on
comments seems to e.g. redirect FDC interrupts:
https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git/tree/arch/m68k/atari/config.c#n394
In this code snippet, "FDC" does not refer to the floppy disk controller
(or to interrupts, at all). It's a typo in the comments. Looking at the
actual code, it become apparent that this bit of code is related to
setting the *FC* mask and value of one of the transparent translation
registers. This is indeed only required when using actual VME bus cards.
Good to know, thanks!
- Eero