5 Give the value in R2 after the following code is executed

5. Give the value in R2 after the following code is executed:

LDR R1, = 0x55555555

MVN R0,#0

EOR R2, R1, R0

Solution

AREA Loadcon, CODE, READONLY ENTRY ; Mark first instruction to execute start BL func1 ; Branch to first subroutine BL func2 ; Branch to second subroutine stop MOV r0, #0x18 ; angel_SWIreason_ReportException LDR r1, =0x20026 ; ADP_Stopped_ApplicationExit SWI 0x123456 ; ARM semihosting SWI func1 LDR r0, =42 ; => MOV R0, #42 LDR r1, =0x55555555 ; => LDR R1, [PC, #offset to ; Literal Pool 1] LDR r2, =0xFFFFFFFF ; => MVN R2, #0 MOV pc, lr LTORG ; Literal Pool 1 contains ; literal Ox55555555 func2 LDR r3, =0x55555555 ; => LDR R3, [PC, #offset to ; Literal Pool 1] ; LDR r4, =0x66666666 ; If this is uncommented it ; fails, because Literal Pool 2 ; is out of reach MOV pc, lr LargeTable SPACE 4200 ; Starting at the current location, ; clears a 4200 byte area of memory ; to zero END ; Literal Pool 2 is empty