Programming Cautions For U.s. Programmers - Nintendo GAME BOY Programming Manual

Appendix 1: Programming Cautions

6. PROGRAMMING CAUTIONS FOR U.S. PROGRAMMERS

If you are unable to verify that the system is a Super Game Boy, and the Accumulator returns the
same value if the game is inserted in the Super Game Boy or original Game Boy hardware, follow the
instructions below.
If your game is Super Game Boy (SGB) enhanced, then you just need to use the MLT_REQ function.
Otherwise, you must use the SGB libraries to verify if the game is in an SGB. (These libraries are
located in the CGB files section of Wario World under SGBlib.zip.) You will need to call the SGBCHK
function from these libraries right after the Soft Reset label. To use this function, you must set the ROM
Registration area for SGB ($146h) to $03, which allows access to the SGB REgisters. (Don't forget to
readjust the Complement Check.)
Also, on the Software Submission sheet, make sure you note that the game has a $03 in address
$146, but in the remarks section, explain that the game doesn't use any of the SGB features.
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