I'm a bit confused by all the fields in cs_arm_op for ARM_OP_MEM. At first I thought the calculation would be something like

op.mem.base+op.mem.disp+doShift(op.mem.index*op.mem.scale, op.shift)

but it appears that for an instruction like 82 f6 11 e7 ldr pc, [r1, -r2, lsl #13] we have op.mem.scale==1 and op.subtracted==1. So, what is the generally correct procedure to calculate the effective address? What are some examples of instructions where op.subtracted==0 and op.mem.scale==-1?