SMW Memory Map
|$7E14B6||2 bytes||Sprites||Used for multiple purposes.
The 16-bit address is the Y position of the brown chained platform sprite at sin a = 0. It is in fact a mirror of the sprite Y position, which always stays the same. By subtracting the horizontal radius ($7E:14BF) from this address, the center position to revolve around is calculated. Since $7E:14BF is always zero, the center position and this address always have the same identical value.
The 16-bit address is also used to determine Iggy/Larry interactive Y position, as well as the player's fireball Y position during this boss battle.
$7E:14B6 is also a timer that is set to #$FF when Bowser begins with the Big Steelie attack. Note that the Big Steelie is thrown when this timer is at #$80.
And finally, $7E:14B7 holds the X position of each new fireball that falls from the sky in the Bowser battle, as well as the index to the sound effects that are generated with them (table at $03:A841).