Super NES Programming/multiplication

Here is a subroutine multiplying 16-bit A with 8-bit Y, with the lower 16-bit result in A and the top 8-bits result in Y.

This uses the Mode-7 registers. If you are already using Mode-7 registers, you can use this subroutine instead. This will produce errors if Mode-7 graphics are currently being rendered by the PPU.