Wiki Error?

67726e · Post by **67726e** » Tue Dec 14, 2010 5:12 pm

http://wiki.nesdev.com/w/index.php/PPU_ ... _.3E_write

The line states that writing #$30 to $2001 will produce a monochrome display. It seems that is incorrect. Writing #$1F will produce the monochrome display. Writing #$30 will only remove the background rendering and intensify red.

Dwedit · Post by **Dwedit** » Tue Dec 14, 2010 5:35 pm

No, it says that enabling the monochrome bit is like doing a bitwise AND of all the colors of the palette with 0x30.

koitsu · Post by **koitsu** » Tue Dec 14, 2010 10:23 pm

I've updated the phrasing of the bit in question. Instead of saying "1: AND all ...", I've changed it to "1: logically AND all...", which should act as extra clarification.

tokumaru · Post by **tokumaru** » Wed Dec 15, 2010 12:05 am

The problem is using "AND" as if it was a verb. Maybe it should say "ignore bits 0-3 of the palette entries, effectively producing a monochrome display"

67726e · Post by **67726e** » Wed Dec 15, 2010 4:27 am

koitsu wrote:I've updated the phrasing of the bit in question. Instead of saying "1: AND all ...", I've changed it to "1: logically AND all...", which should act as extra clarification.

That makes it much clearer.

thefox · Post by **thefox** » Wed Dec 15, 2010 5:06 am

"Logically AND" makes me think of logical conjunction... I would do something along the lines of what tokumaru said.

Post by **tepples** » Wed Dec 15, 2010 8:31 am

C, C++, Java, PHP, and numerous other C-family languages make a distinction between bitwise AND (&) and logical AND (&&). Bitwise AND is the operation performed here. Logical AND is "1 if both values are nonzero; otherwise 0". I just rewrote much of that section to get more of the discussion out of the bit chart.

cartlemmy · Post by **cartlemmy** » Wed Dec 15, 2010 9:09 am

tepples wrote:C, C++, Java, PHP, and numerous other C-family languages make a distinction between bitwise AND (&) and logical AND (&&). Bitwise AND is the operation performed here. Logical AND is "1 if both values are nonzero; otherwise 0". I just rewrote much of that section to get more of the discussion out of the bit chart.

Yep, if I saw logical AND I'd really be confused.