FSUBR             Subtract Real Reversed      Exception Flags: I D O U P

SUBR [[destination,] source]

       Logic:      ST(1) . ST - ST(1), pop stack    (no operands)
                   ST . memory location - ST        (source only)
                   ST . ST(i) -ST                   (destination, source)

     FSUBR acts like FSUB, except that it reverses the order of the operands.
     In the no operands form, ST(1) and ST are the implied operands. ST(1) is
     subtracted from ST, the result is placed in ST(1), and the stack is
     popped.

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   Operands            Clocks         Bytes           Example
   FSUBR               70-100           3             FSUBR
   FSUBR MEMORY_REAL   90-125+EA        5             FSUBR REAL_NUMBER
   FSUBR ST(i), ST     75-105           3             FSUBR ST(1),ST
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        Note:          In the FSUBR destination, source form, ST must
                       be one of the operands.