diff options
Diffstat (limited to 'CAN-binder/libs/bitfield-c/src/bitfield/8byte.c')
-rw-r--r-- | CAN-binder/libs/bitfield-c/src/bitfield/8byte.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/CAN-binder/libs/bitfield-c/src/bitfield/8byte.c b/CAN-binder/libs/bitfield-c/src/bitfield/8byte.c new file mode 100644 index 0000000..9325ed1 --- /dev/null +++ b/CAN-binder/libs/bitfield-c/src/bitfield/8byte.c @@ -0,0 +1,61 @@ +#include <bitfield/bitfield.h> +#include <bitfield/8byte.h> +#include <stddef.h> +#include <limits.h> +#include <string.h> + +#define EIGHTBYTE_BIT (8 * sizeof(uint64_t)) + +uint8_t eightbyte_get_nibble(const uint64_t source, const uint8_t nibble_index, + const bool data_is_big_endian) { + return (uint8_t) eightbyte_get_bitfield(source, NIBBLE_SIZE * nibble_index, + NIBBLE_SIZE, data_is_big_endian); +} + +uint8_t eightbyte_get_byte(uint64_t source, const uint8_t byte_index, + const bool data_is_big_endian) { + if(data_is_big_endian) { + source = __builtin_bswap64(source); + } + return (source >> (EIGHTBYTE_BIT - ((byte_index + 1) * CHAR_BIT))) & 0xFF; +} + +// TODO is this funciton necessary anymore? is it any faster for uint64_t than +// get_bitfield(data[], ...)? is the performance better on a 32 bit platform +// like the PIC32? +uint64_t eightbyte_get_bitfield(uint64_t source, const uint16_t offset, + const uint16_t bit_count, const bool data_is_big_endian) { + int startByte = offset / CHAR_BIT; + int endByte = (offset + bit_count - 1) / CHAR_BIT; + + if(!data_is_big_endian) { + source = __builtin_bswap64(source); + } + + uint8_t* bytes = (uint8_t*)&source; + uint64_t ret = bytes[startByte]; + if(startByte != endByte) { + // The lowest byte address contains the most significant bit. + uint8_t i; + for(i = startByte + 1; i <= endByte; i++) { + ret = ret << 8; + ret = ret | bytes[i]; + } + } + + ret >>= 8 - find_end_bit(offset + bit_count); + return ret & bitmask(bit_count); +} + +bool eightbyte_set_bitfield(uint64_t value, const uint16_t offset, + const uint16_t bit_count, uint64_t* destination) { + if(value > bitmask(bit_count)) { + return false; + } + + int shiftDistance = EIGHTBYTE_BIT - offset - bit_count; + value <<= shiftDistance; + *destination &= ~(bitmask(bit_count) << shiftDistance); + *destination |= value; + return true; +} |