FFPABS.asm

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* (C) COPYRIGHT 1981 BY MOTOROLA INC. *
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*                     FFPABS                                *
*           FAST FLOATING POINT ABSOLUTE VALUE              *
*                                                           *
*  INPUT:  D7 - FAST FLOATING POINT ARGUMENT                *
*                                                           *
*  OUTPUT: D7 - FAST FLOATING POINT ABSOLUTE VALUE RESULT   *
*                                                           *
*      CONDITION CODES:                                     *
*              N - CLEARED                                  *
*              Z - SET IF RESULT IS ZERO                    *
*              V - CLEARED                                  *
*              C - UNDEFINED                                *
*              X - UNDEFINED                                *
*                                                           *
*               ALL REGISTERS TRANSPARENT                   *
*                                                           *
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         XDEF      FFPABS    FAST FLOATING POINT ABSOLUTE VALUE

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* ABSOLUTE VALUE ENTRY POINT *
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FFPABS   AND.B     #$7F,D7   CLEAR THE SIGN BIT
         RTS                 AND RETURN TO THE CALLER

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*                     FFPNEG                                *
*           FAST FLOATING POINT NEGATE                      *
*                                                           *
*  INPUT:  D7 - FAST FLOATING POINT ARGUMENT                *
*                                                           *
*  OUTPUT: D7 - FAST FLOATING POINT NEGATED RESULT          *
*                                                           *
*      CONDITION CODES:                                     *
*              N - SET IF RESULT IS NEGATIVE                *
*              Z - SET IF RESULT IS ZERO                    *
*              V - CLEARED                                  *
*              C - UNDEFINED                                *
*              X - UNDEFINED                                *
*                                                           *
*               ALL REGISTERS TRANSPARENT                   *
*                                                           *
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         XDEF      FFPNEG    FAST FLOATING POINT NEGATE

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* NEGATE ENTRY POINT *
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FFPNEG   TST.B     D7        ? IS ARGUMENT A ZERO
         BEQ.S     FFPRTN    RETURN IF SO
         EOR.B     #$80,D7   INVERT THE SIGN BIT
FFPRTN   RTS                 AND RETURN TO CALLER