SMW Memory Map
|$7E0096||2 bytes||Player||Player Y position (16-bit) within the level, next frame (calculates player position one frame ahead, as opposed to $D3).
It's also used as a player Y position on-screen on the overworld border.
NOTE: the player's Y position is not affected by their powerup, nor whether they are crouching; the point will always be 32 pixels above their feet. However, if riding on Yoshi, their Y position does get offset 16 pixels upwards.
Additionally, during player interaction with blocks on Layer 2, this value is modified to be relative to Layer 2's position rather than Layer 1. This can be checked via $1933, and can be offset back to Layer 1 by subtracting $28.