Is there a need for an arithmetic shift left instruction?
No. A logical shift left moves zeros into the low-order bit, which is correct for both signed and unsigned integers.
sra Instruction
sra d,s,shft # $d ← $s shifted right
# shft bit positions.
# 0 ≤ shft ≤ 31
MIPS
has a shift right arithmetic instruction.
This instructions takes the bit pattern in $s,
arithmetic shifts it right by shft positions,
and deposits the result in register $d.
Register $s is not changed
(unless it is the same as the destination register.)
Sometimes you need to divide by two.
This instruction is faster and
more convenient than the
div
instruction.
Does the sra instruction
give the correct results for unsigned integers?