The CMOS page on the wiki links to two CMOS memory maps.
The first one says the bit 0 of register B deals with DST, bit 1 is 12/24 hour mode, and bit 2 is BCD or BIN. The second one, however, says bit 1 is DST, bit 2 is 12/24 hour, and doesn't give a BCD/BIN bit.
The wiki seems to follow the first one, but Bochs follows the second, so I assume the second is the more correct version. If that's so, is there not a BCD/BIN bit or is it somewhere else?
CMOS register B
Re: CMOS register B
Hi,
Looking at this part of the Bochs source code, it looks like Bochs follows the first one.
For my reference material, I looked at an old document called "PCTIM003.TXT" (which is awesome and covers all timing on old 80x86 machines) and it follows the first one too. The I looked at Ralph Brown's Interrupt List (which comes with a CMOS list, an IO port list, etc) and it also follows the first one (with no mention of the second).
Mostly, as far as I can tell; everything uses the first version, and it's very likely that the second one is wrong.
Cheers,
Brendan
Looking at this part of the Bochs source code, it looks like Bochs follows the first one.
For my reference material, I looked at an old document called "PCTIM003.TXT" (which is awesome and covers all timing on old 80x86 machines) and it follows the first one too. The I looked at Ralph Brown's Interrupt List (which comes with a CMOS list, an IO port list, etc) and it also follows the first one (with no mention of the second).
Mostly, as far as I can tell; everything uses the first version, and it's very likely that the second one is wrong.
Cheers,
Brendan
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