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
111 lines
2.2 KiB
C
Executable File
111 lines
2.2 KiB
C
Executable File
/* DEC *PowerDecimal(pDst,pSrc1,pSrc2)
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*
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* ARGUMENT
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* DEC *pDst,*pSrc1,*pSrc2;
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*
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* DESCRIPTION
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* Calculates pSrc1 to the power pSrc2 and returns the answer in pDst.
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* This provides an x**y power function for DEC numbers. Because of
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* the way we store DEC numbers, the base can't be very large if the
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* power is greater than 3 or 4. A separate function is provided for
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* integral powers, which uses a different algorithm and is MUCH FASTER.
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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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* Pointer to the result if no error, otherwise GM_NULL.
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*
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* ALGORITHM:
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* x**y = e**(y*ln(x)). Therefore, call dlnx() to get the natural log
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* and then multiply by the power of x. Finally, call dexx() to provide
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* e**z.
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*
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* POSSIBLE ERROR CODES
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*
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* GM_NULLPOINTER
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* GM_OVERFLOW
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* GM_UNDERFLOW
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* GM_IMAG
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* GM_PWR0
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*
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* AUTHOR
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* Andy Anderson 05-JAN-1987 17:30
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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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*/
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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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DEC *PowerDecimal(pDst,pSrc1,pSrc2)
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DEC *pDst, *pSrc1, *pSrc2;
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{
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DEC temp, *pt;
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int i;
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_MacStart(GM_DPOW);
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_MacInVarD(pSrc1);
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_MacInVarD(pSrc2);
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_MacOutVarD(pDst);
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if (_MacIsDecN(pSrc1)) {
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_MacErr(GM_IMAG);
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_MacRet(GM_NULL);
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}
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if (_MacIsDecZ(pSrc1)) {
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if (_MacIsDecP(pSrc2)) {
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_MacDZero(pDst);
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_MacRet(pDst);
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}
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else {
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_MacErr(GM_PWR0);
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_MacRet(GM_NULL);
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}
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}
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pt = &temp;
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/* if the power is integer and small enough, use int power rtn */
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if((pSrc2->dc.id == 0) && ((pSrc2->dc.msd == 0) &&
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(pSrc2->ls.lsl[1] == 0L) && (pSrc2->dc.sl[1] == 0))
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&& (!(pSrc2->dc.sl[0] & 0x8000))) {
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i = _IntPwrDec80Bit(pt,pSrc1,ConvDecimalToInt(pSrc2));
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if(i == GM_OVERFLOW) {
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_MacErr(i);
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_MacRet(GM_NULL);
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}
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}
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else {
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(void) _LnDec80Bit(pt, pSrc1);
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i = _MulDec80Bit(pt, pt, pSrc2);
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if(i!=GM_SUCCESS) {
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_MacErr(i);
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_MacRet(GM_NULL);
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}
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i = _ExpDec80Bit(pt, pt);
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if(i==GM_OVERFLOW) {
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_MacErr(i);
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_MacRet(GM_NULL);
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}
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}
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i = _Sq5UnsTo4Uns(pt);
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if(i!=GM_SUCCESS) {
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_MacErr(GM_OVERFLOW);
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_MacRet(GM_NULL);
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}
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if (_MacIsDecZ(pt)) {
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_MacErr(GM_UNDERFLOW);
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}
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_MacDCopy(pDst,pt);
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_MacRet(pDst);
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}
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