diff options
| author | Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> | 2021-10-20 14:41:24 +0100 |
|---|---|---|
| committer | Laurent Vivier <laurent@vivier.eu> | 2021-10-20 16:18:40 +0200 |
| commit | e976459b3b127838befaef57f1587770452a0827 (patch) | |
| tree | 0aae06c78a18a54e7d05071d43c9ea007c9ea40e /hw/misc | |
| parent | 50352cce138ef3b30c1cda28a4df68fff5da3202 (diff) | |
mac_via: update comment for VIA1B_vMystery bit
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-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20211020134131.4392-2-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Diffstat (limited to 'hw/misc')
| -rw-r--r-- | hw/misc/mac_via.c | 4 |
1 files changed, 4 insertions, 0 deletions
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) */ |