On 15/10/2021 07:14, Laurent Vivier wrote:
Le 13/10/2021 à 23:21, Mark Cave-Ayland a écrit :
According to both Linux and NetBSD, port B bit 6 is used on the Quadra 800 to
configure the GLUE logic in A/UX mode. Whilst the name VIA1B_vMystery isn't
particularly descriptive, the patch leaves this to ensure that the constants
in mac_via.c remain in sync with Linux's mac_via.h.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
---
hw/misc/mac_via.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c
index 993bac017d..7a53a8b4c0 100644
--- a/hw/misc/mac_via.c
+++ b/hw/misc/mac_via.c
@@ -130,6 +130,10 @@
* On SE/30, vertical sync interrupt enable.
* 0=enabled. This vSync interrupt shows up
* as a slot $E interrupt.
+ * On Quadra 800 this bit toggles A/UX mode
which
+ * configures the glue logic to deliver some
IRQs
+ * at different levels compared to a classic
+ * Mac.
*/
#define VIA1B_vADBS2 0x20 /* ADB state input bit 1 (unused on IIfx) */
#define VIA1B_vADBS1 0x10 /* ADB state input bit 0 (unused on IIfx) */
I'm not sure we need to keep in sync a word that neither used by linux or qemu
(for now).
Perhaps you can put a word from where it is (NetBSD)?
It seems it's supported by all Quadra, not only Quadra 800 (see NetBSD comment
in mac68k/machdep.c
Anyway:
Reviewed-by: Laurent Vivier <laur...@vivier.eu>
Yeah, it's a hard one: you can see the bit referenced in the via_alt_mapping logic in
Linux but mac_via.h still shows it as VIA1B_vMystery (and indeed, it seems to have
different uses on different machines). The thought behind adding the comment was to
better explain the purpose of VIA1B_vMystery within the series.
ATB,
Mark.
