.text
.global postmod
postmod:
ldrd r0,[r1],r2 ; tricky because r1 is implied as destination
strb r12,[r12],r3 ; stores are okay
strd r12,[r13],r3
ldr r0,[r0],r0 ; ERROR
ldr r0,[r0,+128] ; ok
ldrd r12,[r13],-256 ; ERROR
ldrb r12,[r12],20 ; ERROR
strd r12,[r13],-256 ; ok