How to perform right shift on RISC

Question

I'd like to know how I can perform a right shift on a Reduced Instruction Set Computer that does not offer this operation on it's own.
A left shift can be simply done by adding a register to itself but how about a right shift?

The RISC offers only:

ADD 
NOT
NXOR (XOR)
AND (NAND)

so OR and NOR can all be emulated by several (N)AND and NOT operations.

Multiplication by two can be done, but that is left shift. The RISC does not natively support division and algorithms for that are fairly complicated. — xuma202, Jul 19 '14 at 12:56

Pascal Cuoq · Accepted Answer · 2014-07-19T13:19:28.730

The C program below uses only authorized instructions plus conditional jumps, and it shifts input into output by 1.

If the instruction you are trying to emulate is “shift by n”, then you should start with c equal to 2ⁿ.

unsigned int shift_right(unsigned int input) {
  unsigned int d = 1;
  unsigned int output = 0;
  for (unsigned int c = 2; c <= 0x80000000; c += c)
  {
    if (c & input) 
      output |= d;
    d += d;
  }
  return output;
}

How to perform right shift on RISC

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