ba237a9d91
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
135 lines
2.9 KiB
C
Executable File
135 lines
2.9 KiB
C
Executable File
/* int _IntPwrDec80Bit(pDst,pSrc,i)
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*
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* ARGUMENT
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* DEC *pDst,*pSrc;
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* int i;
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*
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* DESCRIPTION
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* Raises pSrc to the power 'i'. If i<0, raises pSrc to the |i|, then
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* takes the reciprocal(ie, if i<0, then x**i = 1/x**|i|). If x=0, then
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* if i=<0, then error (GM_PWR0), else pDst is set to 1. If x<0, then if the
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* power is odd, the result will be negative, otherwise positive. The
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* absolute value cannot exceed 2**79 -1. Other high-level functions need
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* returns of 2**79 -1, which is what this routine returns.
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*
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* SIDE EFFECTS
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* None.
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*
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* RETURNS
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* GM_SUCCESS if no error, otherwise one of the errors below. Note that
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* it is up to the caller to set any of these (with SetMathError()):
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* GM_OVERFLOW if number is too large;
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* GM_UNDERFLOW too small; or
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* GM_PWR0 if power and base is as described above.
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*
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* AUTHOR
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* Andy Anderson 08-10-87 0930
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* Copyright (C) 1987-1990 Greenleaf Software Inc. All rights reserved.
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*
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* MODIFICATIONS
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*/
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#include <stdio.h>
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#include "gm.h"
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#include "gmsystem.h"
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int _IntPwrDec80Bit(pDst,pSrc,i)
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DEC *pDst,*pSrc;
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int i;
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{
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register int j;
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int k;
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mbool wfRecip, wfIsNeg, wfWasOdd;
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DEC y,z,*py=&y,*pz=&z,*pone;
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j=i;
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/* constant of one for reciprocals */
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pone=&decOne;
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_MacDCopy(py,pone);
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if(j==0) {
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if(_MacIsDecP(pSrc)) {
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_MacDCopy(pDst,pone);
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return(GM_SUCCESS);
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}
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else
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/* 0**0 and -x**0 are undefined */
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return(GM_PWR0);
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}
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/* then find out if final answer will be positive or negative */
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_MacDCopy(pz,pSrc);
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if(_MacIsDecN(pSrc)) {
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_MacDChgs(pz);
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if(j&0x0001)
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wfIsNeg=TRUE; /* negative number to odd exp = neg */
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else
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wfIsNeg=FALSE; /* neg. number to even exp = pos */
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}
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else {
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wfIsNeg=FALSE; /* pos number to any exp = pos */
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}
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_MacDZero(pDst);
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/* then set do reciprocal bit */
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if(j<0) {
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if ((long) j == -32768L) {
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/* -32768 must be handled separately */
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k = _MulDec80Bit(pz, pz, pz);
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if (k == GM_OVERFLOW)
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return(GM_UNDERFLOW);
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j = -16384;
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}
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wfRecip = TRUE;
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j = -j;
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}
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else
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wfRecip = FALSE;
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/* now do the calculation x ** i */
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do {
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wfWasOdd = (j&0x0001) ? TRUE : FALSE;
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j >>= 1; /* divide power by two */
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if(wfWasOdd) {
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k=_MulDec80Bit(py,py,pz);
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if(k!=GM_SUCCESS)
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return(((k==GM_OVERFLOW)^wfRecip) ?
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GM_OVERFLOW : GM_UNDERFLOW);
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if(j==0) {
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if(wfRecip) {
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k=_DivDec80Bit(py,pone,py);
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if(k!=GM_SUCCESS)
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return(k);
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}
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if(wfIsNeg)
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_MacDChgs(py);
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_MacDCopy(pDst,py);
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return(GM_SUCCESS);
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}
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k=_MulDec80Bit(pz,pz,pz);
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if(k!=GM_SUCCESS)
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return(((k==GM_OVERFLOW)^wfRecip) ?
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GM_OVERFLOW : GM_UNDERFLOW);
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}
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else {
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k=_MulDec80Bit(pz,pz,pz); /* z = z * z */
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if(k!=GM_SUCCESS)
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return(((k==GM_OVERFLOW)^wfRecip) ?
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GM_OVERFLOW : GM_UNDERFLOW);
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}
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} while(j>0);
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if(wfRecip) {
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k=_DivDec80Bit(pz,pone,pz);
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if(k!=GM_SUCCESS)
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return(k);
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}
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if(wfIsNeg)
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_MacDChgs(pz);
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_MacDCopy(pDst,pz);
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return(GM_SUCCESS);
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}
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