about summary refs log tree commit diff
path: root/lib/util/wordaccess_64_le.h
blob: 83bbf2bff4c03e96cde9418de8471d5090b45a03 (plain) (blame)
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
/*=============================================================================
  This file is the part of wordaccess.h for use under these
  conditions:

  * GCC (>=3.4), GLIBC
  * 64 bit Little-Endian machines (IA64, X86-64, AMD64)
=============================================================================*/
   
/*  
    64 bit hton and ntoh do not exist.  Here we use bswap_64.
    
    While bswap_64 works on 64 bit data, __builtin_clzl works on "long" which
    may or may not be 64 bits.  Code provided to find the right data type and
    file off any extra when necessary.
*/

#include <byteswap.h>  /* See note above on bswap_64 */

#include "pm.h"
 
typedef uint64_t wordint;
typedef unsigned char wordintBytes[sizeof(wordint)];

static __inline__ wordint
bytesToWordint(wordintBytes bytes) {
    return ((wordint) bswap_64(*(wordint *)bytes));
}



static __inline__ void
wordintToBytes(wordintBytes * const bytesP,
               wordint        const wordInt) {
    *(wordint *)bytesP = bswap_64(wordInt);
}



static __inline__ unsigned int
wordintClz(wordint const x){

    unsigned int s;

    if (x == 0)
        return sizeof(wordint) * 8;

    /* Find the data type closest to 64 bits, and file off any extra. */
    else if ((s=sizeof(long int)) >= 8)
        return (__builtin_clzl((int)x << (s - 8) * 8));
    else if ((s=sizeof(long long int)) >= 8)
        return (__builtin_clzll((long long int)x << (s - 8) * 8));
    else
        pm_error("Long long int is less than 64 bits on this machine"); 
}