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
131 lines
2.7 KiB
C
Executable File
131 lines
2.7 KiB
C
Executable File
/* DEC *SubtractDecimal(pDst,pSrc1,pSrc2)
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*
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* ARGUMENT
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* pDst is a pointer to the destination DEC structure.
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* pSrc1 is a ptr to the source1 DEC structure.
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* pSrc2 is a ptr to the source2 DEC structure.
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*
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* DESCRIPTION
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* Subtracts the value in pSrc1 DEC to the value in pSrc2 DEC
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* and puts the result in dest DEC structure. The sum is calculated
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* to the maximum possible accuracy. The routine requires MINID,
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* the minimum allowed implied decimal.
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*
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* SIDE EFFECTS
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* On overflow, the dest value is indeterminate.
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*
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* RETURNS
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* Returns a pointer to the dest structure unless overflow,
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* when it returns a GM_NULL.
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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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*
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* AUTHOR
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* Jared Levy
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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 "gmsystem.h"
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DEC *SubtractDecimal(pDst,pSrc1,pSrc2)
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DEC *pDst;
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DEC *pSrc1,*pSrc2;
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{
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DEC t1, t2, *pts;
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register int i,j;
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int s1, s2;
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_MacStart(GM_DSUB);
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_MacInVar(pSrc1,GM_NULL);
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_MacInVar(pSrc2,GM_NULL);
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_MacOutVar(pDst,GM_NULL);
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/* if the source id's are different, make them equal with as much accuracy
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as is possible, and protect source fields from change */
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/* line up decimal places */
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i = pSrc1->dc.id-pSrc2->dc.id;
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if (i) {
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pts = &t1;
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_MacDCopy(pts, pSrc1);
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pts = &t2;
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_MacDCopy(pts, pSrc2);
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_MacDChgs(pts);
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if (i<0) {
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pSrc1 = &t1;
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pSrc2 = &t2;
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i = -i;
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}
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else {
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pSrc2 = &t1;
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pSrc1 = &t2;
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}
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j = _MulUnsArrByPwrOf10Limited(
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pSrc1->dc.sl, i, 4);
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pSrc1->dc.id += j;
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if (j<i)
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_DivUnsArrByPwrOf10(pSrc2->dc.sl, 4, i-j);
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}
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s1 = pSrc1->dc.attr & 0x0001;
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s2 = pSrc2->dc.attr & 0x0001;
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if (i==0)
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s2=1-s2;
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/* Subtract the numbers */
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pDst->dc.id = pSrc1->dc.id;
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if (s1 == s2) {
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/* Add absolute values if signs are equal */
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_AddUnsArrToUnsArr(pSrc1->dc.sl, pSrc2->dc.sl,
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pDst->dc.sl,5);
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/* if the first addition is an overflow, round down and try again */
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if (pDst->dc.sl[3] >= 32768L) {
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if (pSrc1->dc.id <= GM_MINID) {
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_MacErr(GM_OVERFLOW);
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_MacRet(GM_NULL);
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}
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_DivUnsArrByUns(pDst->dc.sl, 10, 4);
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pDst->dc.id--;
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}
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/* sign of pDst same as sign of sources */
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pDst->dc.attr = s1;
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}
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else {
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/* subtract larger absolute value from smaller if signs are different */
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if (_CompareUnsArr(pSrc1->dc.sl,
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pSrc2->dc.sl, 5) >= 0) {
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/* pSrc1 has larger absolute value */
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(void) _SubUnsArrFromUnsArr(pSrc1->dc.sl,
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pSrc2->dc.sl,
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pDst->dc.sl,5);
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/* sum has same sign as pSrc1 */
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pDst->dc.attr = s1;
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}
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else {
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/* pSrc2 has larger absolute value */
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(void) _SubUnsArrFromUnsArr(pSrc2->dc.sl,
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pSrc1->dc.sl,
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pDst->dc.sl,5);
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/* sum has same sign as pSrc2 */
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pDst->dc.attr = s2;
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}
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}
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_MacRet(pDst);
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}
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