Here's some off the cuff code to quickly determine if your divisor is a simple power of 2
R0 = divisor
R1 = dividend
CLZ r4,r0
MOV r5,r0,LSL r4 ; shift it up to compare with 0x80000000
CMP r5,#0x80000000 ; is it a simple power of 2?
RSBEQ r6,r4,#31 ; get the shift amount...