hw/m68k/q800: fix PROM checksum and MAC address storage

The checksum used by MacOS to validate the PROM content is an exclusive-OR
rather than a sum over the corresponding bytes. In addition the MAC address
must be stored in bit-reversed format as indicated in comments in Linux's
macsonic.c.

With the PROM contents fixed MacOS starts to probe the device registers
when AppleTalk is enabled in the Control Panel.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Tested-by: Finn Thain <fthain@linux-m68k.org>
Message-Id: <20210625065401.30170-8-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
This commit is contained in:
Mark Cave-Ayland 2021-06-25 07:53:58 +01:00 committed by Philippe Mathieu-Daudé
parent db1ffc32dd
commit 846feac2ae

View file

@ -334,11 +334,8 @@ static void q800_init(MachineState *machine)
prom = memory_region_get_ram_ptr(dp8393x_prom);
checksum = 0;
for (i = 0; i < 6; i++) {
prom[i] = nd_table[0].macaddr.a[i];
checksum += prom[i];
if (checksum > 0xff) {
checksum = (checksum + 1) & 0xff;
}
prom[i] = bitrev8(nd_table[0].macaddr.a[i]);
checksum ^= prom[i];
}
prom[7] = 0xff - checksum;