_rotl8, _rotl16

Microsoft Specific

Rotate the input values to the left to the most significant bit (MSB) by a specified number of bit positions.


unsigned char _rotl8(
   unsigned char value,
   unsigned char shift
unsigned short _rotl16(
   unsigned short value,
   unsigned char shift


[in] The value to rotate.

[in] The number of bits to rotate.

Return Value

The rotated value.


Intrinsic Architecture
_rotl8 x86, ARM, x64
_rotl16 x86, ARM, x64

Header file <intrin.h>


Unlike a left-shift operation, when executing a left rotation, the high order bits that fall off the high end are moved into the least significant bit positions.


// rotl.cpp
#include <stdio.h>
#include <intrin.h>

#pragma intrinsic(_rotl8, _rotl16)

int main()
    unsigned char c = 'A', c1, c2;

    for (int i = 0; i < 8; i++)
       printf_s("Rotating 0x%x left by %d bits gives 0x%x\n", c,
               i, _rotl8(c, i));

    unsigned short s = 0x12;
    int nBit = 10;

    printf_s("Rotating unsigned short 0x%x left by %d bits gives 0x%x\n",
            s, nBit, _rotl16(s, nBit));
Rotating 0x41 left by 0 bits gives 0x41
Rotating 0x41 left by 1 bits gives 0x82
Rotating 0x41 left by 2 bits gives 0x5
Rotating 0x41 left by 3 bits gives 0xa
Rotating 0x41 left by 4 bits gives 0x14
Rotating 0x41 left by 5 bits gives 0x28
Rotating 0x41 left by 6 bits gives 0x50
Rotating 0x41 left by 7 bits gives 0xa0
Rotating unsigned short 0x12 left by 10 bits gives 0x4800

END Microsoft Specific

See also

_rotr8, _rotr16
Compiler Intrinsics