Super Mario Bros. 1 - RAM $089F?

[SMB2J-2Q]

According to ShaneM, he found a RAM address that doppelganger had never known about when he first disassembled Super Mario Bros. 1: $089F, which would probably have the label "Player_Y_Scroll". More about that here:
https://forums.nesdev.org/viewtopic.php?p=138084#p138084

ShaneM made this discovery while trying to fix a bug related to the platform behavior in Worlds 3-3, 4-3 and 6-3.

~Ben

[KingMike]

Are you sure you're talking about a ROM address or a RAM address?

The NES only has 2KB of RAM, so it only goes from $0 to 07FF, and then loops, so $089F is the same as $009F.

[SMB2J-2Q]

Are you sure you're talking about a ROM address or a RAM address?

The NES only has 2KB of RAM, so it only goes from $0 to 07FF, and then loops, so $089F is the same as $009F.

Mike,

RAM address.

Here's what hamtaro126 said, which is in line with what you say:

Anything using $0800-0FFF, $1000-17FF, and $1800-1FFF will equal to $0000-$07FF, As they are mirrored in the NES's internal RAM... Therefore $089F equals $009F, or simply $9F in zero page, which equals to both ''SprObject_Y_Speed'' and ''Player_Y_Speed'' in the original disassemblies.

ShaneM then says...

Right, for RAM. When I said $E4 earlier as the address created for this fix on the SNES, I meant $7E00E4. I forgot that Geiger's debugger gives the ROM, RAM, SRAM etc. in hex mode, too. Anyway, my fix does not do the same thing as on the SNES, which bases its fix on horizontal acceleration while I make use of vertical. Because $06FF was the closest one that I originally had but that didn't quite fix this. So if anyone borrows my fix, credit me and replace the $06FF from earlier with $089F, and change the BEQ to BMI; everything else is the same to correct this glitch with invisible blocks. --ShaneM

Therefore, I wonder if what he found is really just $9F?

~Ben