Subroutine to spawn a Yoshi Fireball, which uses the value in $7E:0000 to determine what speed values to use. After it returns, the value in $7E:0000 will be decremented by 1.
- $01F299 (1 byte): extended sprite number to spawn. By default it's $11 (Yoshi Fireball).
- $01F2D9 (3 bytes): X speed to give the fireball. By default it's $28,$24,$24 (middle, up, down fireball respectively).
- $01F2DC (3 bytes): Y speed to give the fireball. By default it's $00,$F8,$08 (middle, up, down fireball respectively).