Expects: AX    001bH
Returns: BX    horizontal speed, in mickeys-per-pixel
CX    vertical speed, in mickeys-per-pixel
DX    speed-doubling threshold, in mickeys-per-second
Info: This obtains the current mouse motion-to-pointer motion
variables.  See INT 33H 000fH and INT 33H 0013H for details.

You may use this function, tweak one or more variables, then call
INT 33H 001aH to install the modifications.

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INT 33H 001bH: Query Mouse Sensitivity