◄Summary►  ◄Timings►
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Calculate 2(^X)-1
 
Syntax:  F2XM1
 
Calculates Y = 2(^X) - 1. X is taken from ST. The result, Y, is returned
in ST. X must be in the range 0 ≤ X ≤ 0.5 on the 8087 and 80287, or in
the range -1.0 ≤ X ≤ +1.0 on the 80387.
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