campo-sirio/gfm/dpowi.c
alex ba237a9d91 Patch level : no patch
Files correlati     :
Ricompilazione Demo : [ ]
Commento            :
Aggiunti i sorgenti per Greenleaf Math Library (gfm.dll)


git-svn-id: svn://10.65.10.50/trunk@10079 c028cbd2-c16b-5b4b-a496-9718f37d4682
2002-02-26 12:19:02 +00:00

83 lines
1.7 KiB
C
Executable File

/* DEC *PowerInteger(pDst,pSrc,i)
*
* ARGUMENT
* DEC *pDst,*pSrc;
* int i;
*
* DESCRIPTION
* Raises pSrc to the power 'i'. If i<0, raises pSrc to the |i|, then
* takes the reciprocal(ie, if i<0, then x**i = 1/x**|i|). If x=0, then
* if i=<0, then error (GM_NAN), else pDst is set to 1. If x<0, then if the
* power is odd, the result will be negative, otherwise positive. The
* absolute value cannot exceed 2**63 -1. Note we call dpoxi() because
* other high-level functions need returns of 2**79 -1, which is what
* this routine gets back and then sqeezes it back to 64-bits.
*
* SIDE EFFECTS
* *pDst is indeterminate on overflow, underflow. It is undisturbed
* on GM_NULLPOINTER.
*
* RETURNS
* Ptr to pDst if no errors, otherwise GM_NULL.
*
* POSSIBLE ERROR CODES
*
* GM_NULLPOINTER
* GM_OVERFLOW
* GM_UNDERFLOW
*
* AUTHOR
* Andy Anderson 08-05-87 1130
* Copyright (C) 1987-1990 Greenleaf Software Inc. All rights reserved.
*
* MODIFICATIONS
*
*/
#include <stdio.h>
#include "gm.h"
#include "gmsystem.h"
DEC *PowerInteger(pDst,pSrc,i)
DEC *pDst,*pSrc;
int i;
{
int wRetVal;
_MacStart(GM_DPOWI);
_MacInVarD(pSrc);
_MacOutVarD(pDst);
if (_MacIsDecZ(pSrc) && (i<=0)) {
_MacErr(GM_PWR0);
_MacRet(GM_NULL);
}
if (_MacIsDecZ(pSrc)) {
_MacDZero(pDst);
_MacRet(pDst);
}
wRetVal=_IntPwrDec80Bit(pDst,pSrc,i);
/* then see if success */
if(wRetVal == GM_OVERFLOW) {
_MacErr(wRetVal);
_MacRet(GM_NULL);
}
/* then try to reduce to 64-bit */
wRetVal = _Sq5UnsTo4Uns(pDst); /* places or it's an error */
if(wRetVal != GM_SUCCESS) {
_MacErr(GM_OVERFLOW);
_MacRet(GM_NULL);
}
if (_MacIsDecZ(pDst)) {
_MacErr(GM_UNDERFLOW);
}
_MacRet(pDst);
}