Our debugger might say a function starts at address 0x8000, but if it is a function using Thumb instructions we must actually use the address 0x8001 (depending on context). Finally we note that we can inspect the current mode in gdb by using the “i r cpsr” command. Bit 0x20 will be set
if we are in Thumb mode, i.e. Thumb mode is set if (cpsr & 0x20) != 0.
blx 0x82ec ; branch to 0x82ec (and switch mode)
bl 0x8398 ; branch to 0x8298 (don't switch mode)
add r12, r12, #8, 20 ; r12 = 0x8000
; 0x8000 = RotateRight(8, 2*20) [ref]
mov sp, r7 ; set stack pointer to original value
pop {r7, pc} ; restore r7 and return to caller