         ttl       ieee format equivalent arctangent (iefatan)
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* (c) copyright 1981 by motorola inc. *
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*************************************************
*                  iefatan                      *
*     ieee format equivalent arctangent         *
*                                               *
*  input:   d7 - ieee format argument           *
*                                               *
*  output:  d7 - ieee format arctangent radian  *
*                result                         *
*                                               *
*     all other registers totally transparent   *
*                                               *
*  condition codes:                             *
*        z - set if result is zero              *
*        n - cleared                            *
*        v - set if result is nan (not-a-number)*
*            (set if the input argument was nan)
*        c - undefined                          *
*        x - undefined                          *
*                                               *
*          all other registers transparent      *
*                                               *
*          maximum stack used:   54 bytes       *
*                                               *
*                                               *
*  notes:                                       *
*    1) see the mc68344 user's guide for details*
*       on ieee format range limitations.       *
*    2) spot checks show at least six digit     *
*       precision on all sampled cases.         *
*                                               *
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         page
iefatan  idnt  1,1 ieee format equivalent arctangent
 
         opt       pcs
 
         section   9
 
         xdef      iefatan                       entry point
 
         xref      ffpatan                fast floating point arctangent
         xref      iefsop            front-end single operand convert
         xref      ieftieee          back-end return ieee format
         xref      ffpfieee          ffp to ieee convert routine
         xref      ffpcpyrt            copyright stub
 
********************
* arctangent entry *
********************
 
* save registers and convert argument
iefatan  jsr       iefsop    convert the single argument
         bra.s     iefnrm    +0 branch normalized
* argument was infinite                  +2 infinity
         jsr       ffpfieee  convert to maximum values allowed in ffp format
 
* argument was normalized
iefnrm   jsr       ffpatan   call ffp arctangent routine
         jmp       ieftieee  return in ieee format
 
         end

   ffpatan   call ffp arctangent routine
         jmp       ieftieee  return in ieee format
 
         end

   ffpatan   call ffp arctangent routine
         jmp       ieftieee  return in ieee format
 
         end

   ffpatan   call ffp arctangent routine
         jmp       ieftieee  return in ieee format
 
         end

