log2.h revision e2e838afcf03e603a41a0455846eaf9614537c16 
1
2/*
3 ** Copyright 2003-2010, VisualOn, Inc.
4 **
5 ** Licensed under the Apache License, Version 2.0 (the "License");
6 ** you may not use this file except in compliance with the License.
7 ** You may obtain a copy of the License at
8 **
9 **     http://www.apache.org/licenses/LICENSE-2.0
10 **
11 ** Unless required by applicable law or agreed to in writing, software
12 ** distributed under the License is distributed on an "AS IS" BASIS,
13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 ** See the License for the specific language governing permissions and
15 ** limitations under the License.
16 */
17
18
19/********************************************************************************
20*
21*      File             : log2.h
22*      Purpose          : Computes log2(L_x)
23*
24********************************************************************************
25*/
26#ifndef __LOG2_H__
27#define __LOG2_H__
28
29/*
30********************************************************************************
31*                         INCLUDE FILES
32********************************************************************************
33*/
34#include "typedef.h"
35
36/*
37********************************************************************************
38*                         DEFINITION OF DATA TYPES
39********************************************************************************
40*/
41
42/*
43********************************************************************************
44*                         DECLARATION OF PROTOTYPES
45********************************************************************************
46*/
47void Log2 (
48		Word32 L_x,        /* (i) : input value                                 */
49		Word16 *exponent,  /* (o) : Integer part of Log2.   (range: 0<=val<=30) */
50		Word16 *fraction   /* (o) : Fractional part of Log2. (range: 0<=val<1)*/
51	  );
52
53void Log2_norm (
54		Word32 L_x,         /* (i) : input value (normalized)                    */
55		Word16 exp,         /* (i) : norm_l (L_x)                                */
56		Word16 *exponent,   /* (o) : Integer part of Log2.   (range: 0<=val<=30) */
57		Word16 *fraction    /* (o) : Fractional part of Log2. (range: 0<=val<1)  */
58	       );
59
60#endif  //__LOG2_H__
61
62
63