◄Summary►  ◄Timings►
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Y log(sub2)(X+1)
 
Syntax:  FYL2XP1
 
Calculates Z = Y log(sub2)(X + 1). X is taken from ST and Y from ST(1).
The stack is popped once and the result, Z, replaces Y in ST. X must be
in the range 0 ≤ |X| < (1 - (√2 / 2)). Y must be in the range -∞ < Y < ∞.
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