lispdoc  results for decodefloat 
(decodefloat f)  Function: Return three values: 1) a floatingpoint number representing the significand. This is always between 0.5 (inclusive) and 1.0 (exclusive). 2) an integer representing the exponent. 3) 1.0 or 1.0 (i.e. the sign of the argument.)

Mentioned in: CLtL2  12.6. Type Conversions and Component Extractions on Numbers HyperSpec  Function DECODEFLOAT, SCALEFLOAT, FLOATRADIX, FLOATSIGN, FLOATDIGITS, FLOATPRECISION, INTEGERDECODEFLOAT  
(integerdecodefloat x)  Function: Return three values: 1) an integer representation of the significand. 2) the exponent for the power of 2 that the significand must be multiplied by to get the actual value. This differs from the DECODEFLOAT exponent by FLOATDIGITS, since the significand has been scaled to have all its digits before the radix point. 3) 1 or 1 (i.e. the sign of the argument.)

Mentioned in: CLtL2  12.6. Type Conversions and Component Extractions on Numbers HyperSpec  Function DECODEFLOAT, SCALEFLOAT, FLOATRADIX, FLOATSIGN, FLOATDIGITS, FLOATPRECISION, INTEGERDECODEFLOAT  
By Bill Moorier 