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40
41 /*
42 // Purpose:
43 // Intel(R) Integrated Performance Primitives. Cryptography Primitives.
44 // Internal Unsigned BNU misc functionality
45 //
46 // Contents:
47 // cpNTZ_BNU()
48 //
49 */
50
51 #include "owncp.h"
52 #include "pcpbnumisc.h"
53
54
55 /*F*
56 // Name: cpNTZ_BNU
57 //
58 // Purpose: Returns number of trailing zeros of the BNU.
59 //
60 // Returns:
61 // number of trailing zeros of the BNU
62 //
63 // Parameters:
64 // x BigNum x
65 //
66 *F*/
67
cpNTZ_BNU(BNU_CHUNK_T x)68 cpSize cpNTZ_BNU(BNU_CHUNK_T x)
69 {
70 cpSize ntz = BNU_CHUNK_BITS;
71 if(x) {
72 ntz = 0;
73 #if (BNU_CHUNK_BITS==BNU_CHUNK_64BIT)
74 if( 0==(x & 0x00000000FFFFFFFF) ) { ntz+=32; x>>=32; }
75 if( 0==(x & 0x000000000000FFFF) ) { ntz+=16; x>>=16; }
76 if( 0==(x & 0x00000000000000FF) ) { ntz+= 8; x>>= 8; }
77 if( 0==(x & 0x000000000000000F) ) { ntz+= 4; x>>= 4; }
78 if( 0==(x & 0x0000000000000003) ) { ntz+= 2; x>>= 2; }
79 if( 0==(x & 0x0000000000000001) ) { ntz++; }
80 #else
81 if( 0==(x & 0x0000FFFF) ) { ntz+=16; x>>=16; }
82 if( 0==(x & 0x000000FF) ) { ntz+= 8; x>>= 8; }
83 if( 0==(x & 0x0000000F) ) { ntz+= 4; x>>= 4; }
84 if( 0==(x & 0x00000003) ) { ntz+= 2; x>>= 2; }
85 if( 0==(x & 0x00000001) ) { ntz++; }
86 #endif
87 }
88 return ntz;
89 }
90