Mapper 015

Found some issues on the wiki for Mapper 015:

In mode 0, it says the second bank should be "B OR 1". I initially interpreted this to mean a 16K bank starting at the address specified by B or starting at $4000. But, it should actually be "B or B + 16K". Meaning, if bit 0 of B equals 0, then treat B as a pointer to a 32K bank occupying $8000--$FFFF.

With that said, it should start up in mode 0 with B set to 0. Meaning, $8000--$FFFF initially starts with the first 32K bank of PRG ROM.

"B OR 1" is a bitwise or... + is wrong, because of the statement after ("If bit 0 of B equals 1, then the 16K and 32K modes are identical.")—that's a consequent, not an additional constraint.

We could rephrase it out as "BBBBB1" or "B bitwise ORed with 1" or "B OR $01"; are any of these sufficiently unambguous?

Doh! I like the first 2 rephrases. Now that I know what it is supposed to be, it seems obvious. My bad. Thanks.