       ttl     ieee format equivalent abs and neg (iefabs/iefneg)
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* (c) copyright 1981 by motorola inc. *
***************************************
 
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*                     iefabs                                *
*  fast floating point ieee format equivalent absolute value*
*                                                           *
*  input:  d7 - ieee format number argument                 *
*                                                           *
*  output: d7 - ieee format number absolute value result    *
*                                                           *
*      condition codes:                                     *
*              n - cleared                                  *
*              z - set if result is zero                    *
*              v - set if result is nan (not-a-number)      *
*                  (occurs only if input argument is nan)   *
*              c - undefined                                *
*              x - undefined                                *
*                                                           *
*               all registers transparent                   *
*                                                           *
*            maximum stack used:   24 bytes                 *
*                                                           *
*  notes:                                                   *
*    1) this routine properly handles all ieee floating     *
*       point values and number types.                      *
*    2) if the input argument is a nan (not-a-number) then  *
*       it will be returned as the result with the "v" bit  *
*       set in the condition code register.                 *
*                                                           *
*************************************************************
         page
iefabs idnt    1,1  ieee format equivalent abs and neg
 
         opt       pcs
 
         xdef      iefabs    ieee format absolute value
 
         xref      iefsop   single argument conversion routine
         xref      iefrtod7 return caller's original d7 as result
         xref      ffpcpyrt copyright notice
 
         section  9
 
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* absolute value entry point *
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iefabs   jsr       iefsop    direct return to caller if nan encountered
         nop                 +0 normalized return (or zero or denormalized)
*                                       +2 infinity return
 
* all values may be absolutized by forcing a plus sign on the original value
         bclr.b    #7,16(sp)  clear sign bit of original value
         jmp       iefrtod7   and return original value altered a wee bit
         page
*************************************************************
*                     iefneg                                *
*  fast floating point ieee format equivalent negate        *
*                                                           *
*  input:  d7 - ieee format number argument                 *
*                                                           *
*  output: d7 - ieee format number negated result           *
*                                                           *
*      condition codes:                                     *
*              n - set if result is negative                *
*              z - set if result is zero                    *
*              v - set if result is nan (not-a-number)      *
*                  (occurs only if input argument is nan)   *
*              c - undefined                                *
*              x - undefined                                *
*                                                           *
*               all registers transparent                   *
*                                                           *
*           maximum stack used:     24 bytes                *
*                                                           *
*  notes:                                                   *
*    1) this routine properly handles all ieee floating     *
*       point values and number types.                      *
*    2) if the input argument is a nan (not-a-number) then  *
*       it will be returned as the result with the "v" bit  *
*       set in the condition code register.                 *
*                                                           *
*************************************************************
         page
         xdef      iefneg    ieee format negate
 
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* negate entry point *
**********************
iefneg   jsr       iefsop    direct return to caller if nan encountered
         nop                 +0 normalized return (or zero or denormalized)
*                                       +6 both infinity return
 
* all values may be negated by inverting the sign bit of the original value
         bchg.b    #7,16(sp) negate original sign bit
         jmp       iefrtod7  and return this modified original register
 
         end
                                            jmp       iefrtod7  and return this modified original register
 
         end
                                            jmp       iefrtod7  and return this modified original register
 
         end
                                            jmp       iefrtod7  and return this modified original register
 
         end
                                        