1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
// Copyright (C) ???? - INRIA - Farid BELAHCENE
// Copyright (C) 2008 - INRIA - Pierre MARECHAL
//
// This file must be used under the terms of the CeCILL.
// This source file is licensed as described in the file COPYING, which
// you should have received as part of this distribution. The terms
// are also available at
// http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
function y = bitget(x,pos)
// BITGET function
// Given an unsigned integer x, this function returns an unsigned integer
// (0 or 1) which is the bit number 'pos' from the representation binary of x
// if x=uint8(19) and pos=2 then bitget returns the 2th bit of the binary form of 19 ('10011') which is 1
// -Inputs :
// x : an unsigned integer
// pos : a positive integer between 1 and the bitmax of the x type
//
// -Output :
// y : an unsigned integer
//
// F.Belahcene
// P. Marechal, 5 Feb 2008
// - Add argument check
// Check input arguments
// =========================================================================
// check number input argument
rhs = argn(2);
if rhs <> 2 then
error(msprintf(gettext("%s: Wrong number of input argument(s): %d expected.\n"),"bitget",2));
end
// case empty matrix
if isempty(x)
if ~isempty(pos) & prod(size(pos))<>1
error(msprintf(gettext("%s: Wrong size for input arguments: Same size expected.\n"),"bitget"));
else
y=[]
return
end
end
// check size
if (size(x,"*")>1) & (size(pos,"*")>1) & (or(size(x)<>size(pos))) then
error(msprintf(gettext("%s: Wrong size for input arguments: Same size expected.\n"),"bitget"));
end
// check type
if (type(x)==1 & (x-floor(x)<>0 | x<0)) ..
| (type(x)==8 & (inttype(x)<10)) ..
| (type(x)<>1 & type(x)<>8) then
error(msprintf(gettext("%s: Wrong input argument #%d: Scalar/matrix of unsigned integers expected.\n"),"bitget",1));
end
if (type(pos)==1 & (pos-floor(pos)<>0 | pos<0)) ..
| (type(pos)==8 & (inttype(pos)<10)) ..
| (type(pos)<>1 & type(pos)<>8) then
error(msprintf(gettext("%s: Wrong input argument #%d: Scalar/matrix of unsigned integers expected.\n"),"bitget",2));
end
// check pos value
select inttype(x)
case 0 then posmax = 52;
case 11 then posmax = 8;
case 12 then posmax = 16;
case 14 then posmax = 32;
end
if (pos>posmax) | (pos<1) then
error(msprintf(gettext("%s: Wrong value for input argument #%d: Must be between %d and %d.\n"),"bitget",2,1,posmax));
end
// Algorithm
// =========================================================================
if size(pos,"*") == 1;
pos = ones(x) * pos;
end
if size(x,"*") == 1;
x = ones(pos) * x;
end
if type(x)==8 then
select inttype(x)
case 11 then
mask = uint8(2^(pos-1));
y = uint8(1 * ((x & mask) > 0));
return;
case 12 then
mask = uint16(2^(pos-1));
y = uint16(1 * ((x & mask) > 0));
return;
case 14 then
mask = uint32(2^(pos-1));
y = uint32(1 * ((x & mask) > 0));
return;
end
else
// type == 1
a = 2^32;
mask = uint32(zeros(pos));
ytemp = uint32(zeros(pos));
if or(pos<=32) then
mask( pos<=32 ) = uint32( 2^(pos(pos<=32) -1 ));
ytemp( pos<=32 ) = uint32( x(pos<=32) - double(uint32(x(pos<=32)/a)) * a ); // permet de récupérer les 32 bits de poid faible
end
if or(pos>32) then
mask( pos>32 ) = uint32( 2^(pos(pos>32) -32 -1 ));
ytemp( pos> 32 ) = uint32( x(pos> 32)/a); // permet de récupérer les 32 bits de poid fort
end
y = 1 * ((ytemp & mask) > 0);
end
endfunction
|
