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  Title:    Compare
 
  Syntax:   FCOM [src]
            FCOMP [src]
            FCOMPP
            FICOM src
            FICOMP src
 
  See also: FTST, FUCOM, FSTSW, SAHF, FXAM, Status Word
 
  Description:
 
     Compares the specified source operand to ST and sets the condition
     codes of the status word according to the result. The instruction
     subtracts the source operand from ST without changing either
     operand. Memory operands can be 32- or 64-bit real numbers or 16-
     or 32-bit integers.
 
     If no operand is specified or if two pops are specified, ST is
     compared to ST(1) and the stack is popped. If one pop is specified
     with an operand, the operand is compared to ST. If one of the
     operands is a NAN, an invalid-operation exception occurs.
     See: FUCOM
 
     The condition codes for FCOM are as follows:
 
     C3     C2     C1     C0     Meaning
 
     0      0      ?      0      ST > source
     0      0      ?      1      ST < source
     1      0      ?      0      ST = source
     1      1      ?      1      ST not comparable to source
                                    -♦-