mov r3, r2, lsl r3 @ create mask
1: ldrexb r2, [r1]
ands r0, r2, r3 @ save old value of bit
- \instr ip, r2, r3 @ toggle bit
- strexb r2, ip, [r1]
- cmp r2, #0
+ \instr r2, r2, r3 @ toggle bit
+ strexb ip, r2, [r1]
+ cmp ip, #0
bne 1b
cmp r0, #0
movne r0, #1