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40 
41 /*
42 //               Intel(R) Integrated Performance Primitives
43 //                   Cryptographic Primitives (ippcp)
44 //
45 //  Contents:
46 //     ippsMod_BN()
47 //
48 */
49 
50 #include "owndefs.h"
51 #include "owncp.h"
52 #include "pcpbn.h"
53 #include "pcptool.h"
54 
55 
56 /*F*
57 //    Name: ippsMod_BN
58 //
59 // Purpose: reduction BigNum.
60 //
61 // Returns:                Reason:
62 //    ippStsNullPtrErr        pA  == NULL
63 //                            pM  == NULL
64 //                            pR  == NULL
65 //    ippStsContextMatchErr   !BN_VALID_ID(pA)
66 //                            !BN_VALID_ID(pM)
67 //                            !BN_VALID_ID(pR)
68 //    ippStsOutOfRangeErr     pR can not hold result
69 //    ippStsBadModulusErr     modulus IppsBigNumState* pM
70 //                             is not a positive integer
71 //    ippStsNoErr             no errors
72 //
73 // Parameters:
74 //    pA    source BigNum
75 //    pB    source BigNum
76 //    pR    reminder BigNum
77 //
78 //    A = Q*M + R, 0 <= R < B
79 //
80 *F*/
81 IPPFUN(IppStatus, ippsMod_BN, (IppsBigNumState* pA, IppsBigNumState* pM, IppsBigNumState* pR))
82 {
83    IPP_BAD_PTR3_RET(pA, pM, pR);
84 
85    pA = (IppsBigNumState*)( IPP_ALIGNED_PTR(pA, BN_ALIGNMENT) );
86    IPP_BADARG_RET(!BN_VALID_ID(pA), ippStsContextMatchErr);
87    pM = (IppsBigNumState*)( IPP_ALIGNED_PTR(pM, BN_ALIGNMENT) );
88    IPP_BADARG_RET(!BN_VALID_ID(pM), ippStsContextMatchErr);
89    pR = (IppsBigNumState*)( IPP_ALIGNED_PTR(pR, BN_ALIGNMENT) );
90    IPP_BADARG_RET(!BN_VALID_ID(pR), ippStsContextMatchErr);
91 
92    IPP_BADARG_RET(BN_NEGATIVE(pM), ippStsBadModulusErr);
93    IPP_BADARG_RET(BN_SIZE(pM)== 1 && BN_NUMBER(pM)[0]==0, ippStsBadModulusErr);
94 
95    IPP_BADARG_RET(BN_ROOM(pR)<BN_SIZE(pM), ippStsOutOfRangeErr);
96 
97    if(cpEqu_BNU_CHUNK(BN_NUMBER(pA), BN_SIZE(pA), 0)) {
98       BN_SIGN(pR) = ippBigNumPOS;
99       BN_SIZE(pR) = 1;
100       BN_NUMBER(pR)[0] = 0;
101    }
102 
103    else {
104       BNU_CHUNK_T* pDataM = BN_NUMBER(pM);
105       cpSize nsM = BN_SIZE(pM);
106       BNU_CHUNK_T* pBuffA = BN_BUFFER(pA);
107       cpSize nsA = BN_SIZE(pA);
108       BNU_CHUNK_T* pDataR = BN_NUMBER(pR);
109       cpSize nsR;
110 
111       COPY_BNU(pBuffA, BN_NUMBER(pA), nsA);
112       nsR = cpMod_BNU(pBuffA, nsA, pDataM, nsM);
113 
114       COPY_BNU(pDataR, pBuffA, nsR);
115       BN_SIZE(pR) = nsR;
116       BN_SIGN(pR) = ippBigNumPOS;
117 
118       if(BN_NEGATIVE(pA) && !(nsR==1 && pDataR[0]==0)) {
119          ZEXPAND_BNU(pDataR, nsR, nsM);
120          cpSub_BNU(pDataR, pDataM, pDataR, nsM);
121          FIX_BNU(pDataR, nsM);
122          BN_SIZE(pR) = nsM;
123       }
124    }
125 
126    return ippStsNoErr;
127 }
128