Información

Autor(es) Arthur van Stratum
Fecha de entrega Sin fecha de envío
Tiempo límite de envío Sin límite de envío
Etiquetas de categoría S2, Level 2, Bitwise operation

Etiquetas

Inicia sesión

[S2] Bitwise operation: cycling bits

In this exercise, we will work with operation on bits. When we speak about the position of a bit, index 0 corresponds to lowest order bit, 1 to the second-lowest order bit, ...

In C source code, you can write a number in binary (base 2) by prefixing it via 0b., e.g. 0b11010 = 26.

This exercise will introduce some non-standard data types which guarantee that the variable has a fixed number of bits. Indeed, on some machines, a int could use 2, 4 or 8 bytes. Hence, if we want to perform bitwise operations, we have to know first on how many bits we are working.

For this, C introduces a new class of variable types :

  • int8_t (signed integer of 8 bits)
  • uint8_t (unsigned integer of 8 bits)
  • uint16_t (unsigned integer of 16 bits)

You can mix uint or int with bit-lengths 8, 16, 32 and 64). These types are defined in <stdint.h>


Write the body of a function cycle_bits, which cycles all bits from n places to the left, according to the formula x[(i+n)%32] = x[i], where x[i] is the i-iest bit of x.

Here is a simple example with bytes. Consider byte 0b01101011. If n is set to 1, then cycle_bits would return 0b11010110. If n is set to 4, then cycle_bits would return 0b10110110.

uint32_t cycle_bits(uint32_t x, uint8_t n) {