Syntax:
BitsOut = FnLSR(BitsIn, NumBits)
Command Availability:
Available on all microcontrollers.
Explanation:
FnLSR (Logical Shift Right) will perform a Bitwise right shift. FnLSR will return BitsIn shifted NumBits to the right, it is equivalent to the 'C' operation:
BitsOut = BitsIn >> NumBits
Each right shift is the equivalent of dividing BitsIn by 2.
BitsIn and NumBits may be may be a variable and of type: Bit, Byte, Word, Long, Constant or another Function.
Zeros are shifted in from the left, Bits that are shifted out are lost.
It is useful for mathematical and logical operations, as well as creating serial data streams or manipulating I/O ports.
Example:
' This program will shift the LEDs on the Microchip PIC Low Pin Count Demo Board
' from Right to Left, that is DS4(RC3) to DS1(RC0) and repeat.
#chip 16f690 ' declare the target Device
#define LEDPORT PORTC ' LEDs on pins 16, 15, 14 and 7
Dim LEDMask as Byte ' Pattern to be displayed
LEDMask = 0b1000 ' Initialise the Patten
Dir LEDPORT Out ' Enable the LED Port.
Do
LEDPORT = LEDMask ' Display the Pattern
wait 500 ms
LEDMask = FnLSR(LEDMask, 1) & 0x0F ' Mask the lower 4 bits
if LEDPORT.0 then LEDMask.3 = 1 ' Restart the sequence
Loop
EndSee Also Bitwise Operations Overview and Conditions
