FXAM
Usage: FXAM Modifies flags: See below.
Examines the contents of the ST(0) register and sets the condition code flags C0, C2, and C3 in the FPU status word to indicate the class of value or number in the register
Examine Class of Value in ST0
FXAM ; D9 E5 [8086,FPU]
FXAM sets the FPU flags C3, C2 and C0 depending on the type of value stored in ST0:
FXAM Results
Class C3 C2 C0
Unsupported format 0 0 0
NaN 0 0 1
Finite number 0 1 0
Infinity 0 1 1
Zero 1 0 0
Empty register 1 0 1
Denormal 1 1 0
Additionally, the C1 flag is set to the sign of the number.
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EXAMPLE:
fxam