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Reference Guide
BitReproducible.cxx
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1// @(#)root/mathcore:$Id$
2// Authors: W. Brown, M. Fischler, L. Moneta 2005
3
5
6#include <sstream>
7#include <iomanip>
8#include <exception>
9
10namespace ROOT {
11namespace Math {
12namespace GenVector_detail {
13
16
18 // Fill_byte_order
19 double x = 1.0;
20 int t30 = 1 << 30;
21 int t22 = 1 << 22;
22 x *= t30;
23 x *= t22;
24 double y = 1;
25 double z = 1;
26 x *= z;
27 for (int k=0; k<6; k++) {
28 x += y*z;
29 y += 1;
30 z *= 256;
31 }
32 // x, in IEEE format, would now be 0x4330060504030201
33 DB8 xb;
34 xb.fD = x;
35 int n;
36 static const int kUNSET = -1;
37 for (n=0; n<8; n++) {
38 fgByte_order[n] = kUNSET;
39 }
40 int order;
41 for (n=0; n<8; n++) {
42 switch ( xb.fB[n] ) {
43 case 0x43:
44 order = 0;
45 break;
46 case 0x30:
47 order = 1;
48 break;
49 case 0x06:
50 order = 2;
51 break;
52 case 0x05:
53 order = 3;
54 break;
55 case 0x04:
56 order = 4;
57 break;
58 case 0x03:
59 order = 5;
60 break;
61 case 0x02:
62 order = 6;
63 break;
64 case 0x01:
65 order = 7;
66 break;
67 default:
69 "Cannot determine byte-ordering of doubles on this system");
70 }
71 if (fgByte_order[n] != kUNSET) {
73 "Confusion in byte-ordering of doubles on this system");
74 }
75 fgByte_order[n] = order;
76 fgByte_order_known = true;
77 }
78 return;
79}
80
81std::string BitReproducible::D2x(double d) {
82 // hex conversion
84 DB8 db;
85 db.fD = d;
86 std::ostringstream ss;
87 for (int i=0; i<8; ++i) {
88 int k = fgByte_order[i];
89 ss << std::hex << std::setw(2) << std::setfill('0') << (int)db.fB[k];
90 }
91 return ss.str();
92}
93
94void BitReproducible::Dto2longs(double d, unsigned int& i, unsigned int& j) {
95 // conversion to 2 longs
97 DB8 db;
98 db.fD = d;
99 i = ((static_cast<unsigned int>(db.fB[fgByte_order[0]])) << 24)
100 | ((static_cast<unsigned int>(db.fB[fgByte_order[1]])) << 16)
101 | ((static_cast<unsigned int>(db.fB[fgByte_order[2]])) << 8)
102 | ((static_cast<unsigned int>(db.fB[fgByte_order[3]])) );
103 j = ((static_cast<unsigned int>(db.fB[fgByte_order[4]])) << 24)
104 | ((static_cast<unsigned int>(db.fB[fgByte_order[5]])) << 16)
105 | ((static_cast<unsigned int>(db.fB[fgByte_order[6]])) << 8)
106 | ((static_cast<unsigned int>(db.fB[fgByte_order[7]])) );
107}
108
109double BitReproducible::Longs2double (unsigned int i, unsigned int j) {
110 // conversion longs to double
111 DB8 db;
112 unsigned char bytes[8];
114 bytes[0] = static_cast<unsigned char>((i >> 24) & 0xFF);
115 bytes[1] = static_cast<unsigned char>((i >> 16) & 0xFF);
116 bytes[2] = static_cast<unsigned char>((i >> 8) & 0xFF);
117 bytes[3] = static_cast<unsigned char>((i ) & 0xFF);
118 bytes[4] = static_cast<unsigned char>((j >> 24) & 0xFF);
119 bytes[5] = static_cast<unsigned char>((j >> 16) & 0xFF);
120 bytes[6] = static_cast<unsigned char>((j >> 8) & 0xFF);
121 bytes[7] = static_cast<unsigned char>((j ) & 0xFF);
122 for (int k=0; k<8; ++k) {
123 db.fB[fgByte_order[k]] = bytes[k];
124 }
125 return db.fD;
126}
127
128} // namespace _GenVector_detail
129} // namespace Math
130} // namespace ROOT
#define d(i)
Definition: RSha256.hxx:102
static double Longs2double(unsigned int i1, unsigned int i2)
static void Dto2longs(double d, unsigned int &i1, unsigned int &i2)
Double_t y[n]
Definition: legend1.C:17
Double_t x[n]
Definition: legend1.C:17
const Int_t n
Definition: legend1.C:16
Namespace for new Math classes and functions.
This file contains a specialised ROOT message handler to test for diagnostic in unit tests.