1 #include <bitfield/bitfield.h>
2 #include <bitfield/8byte.h>
7 #define EIGHTBYTE_BIT (8 * sizeof(uint64_t))
9 unsigned int eightbyte_get_nibble(const uint64_t source, const unsigned int nibble_index,
10 const bool data_is_big_endian) {
11 return (unsigned int) eightbyte_get_bitfield(source, NIBBLE_SIZE * nibble_index,
12 NIBBLE_SIZE, data_is_big_endian);
15 unsigned int eightbyte_get_byte(uint64_t source, const unsigned int byte_index,
16 const bool data_is_big_endian) {
17 if(data_is_big_endian) {
18 source = __builtin_bswap64(source);
20 return (source >> (EIGHTBYTE_BIT - ((byte_index + 1) * CHAR_BIT))) & 0xFF;
23 // TODO is this funciton necessary anymore? is it any faster for uint64_t than
24 // get_bitfield(data[], ...)? is the performance better on a 32 bit platform
26 uint64_t eightbyte_get_bitfield(uint64_t source, const unsigned int offset,
27 const unsigned int bit_count, const bool data_is_big_endian) {
28 int startByte = offset / CHAR_BIT;
29 int endByte = (offset + bit_count - 1) / CHAR_BIT;
31 if(!data_is_big_endian) {
32 source = __builtin_bswap64(source);
35 unsigned int* bytes = (unsigned int*)&source;
36 uint64_t ret = bytes[startByte];
37 if(startByte != endByte) {
38 // The lowest byte address contains the most significant bit.
40 for(i = startByte + 1; i <= endByte; i++) {
46 ret >>= 8 - find_end_bit(offset + bit_count);
47 return ret & bitmask(bit_count);
50 bool eightbyte_set_bitfield(uint64_t value, const unsigned int offset,
51 const unsigned int bit_count, uint64_t* destination) {
52 if(value > bitmask(bit_count)) {
56 int shiftDistance = EIGHTBYTE_BIT - offset - bit_count;
57 value <<= shiftDistance;
58 *destination &= ~(bitmask(bit_count) << shiftDistance);
59 *destination |= value;