RPi_Assembly/ch-02/LongAddition.s

@
@ Example of 64-bit addition with
@       the ADD/ADC instructions.
@

.global _start      @ Provide program starting address

@ Load the registers wit some data.
@ First 64-bit number is 0x00000003FFFFFFFF
_start:
    MOV     R2, #0x00000003
    MOV     R3, #0xFFFFFFFF     @ as; will change to MVN

@ Second 64-bit number is 0x0000000500000001
    MOV     R4, #0x00000005
    MOV     R5, #0x00000001

    ADDS    R1, R3, R5          @ Lower order word
    ADC     R0, R2, R4          @ Higher order word

@ Set up the parameters to exit the program
@ and then call Linux to do it.
@ R0 is the return code and will be wha we
@ calculated above.
    MOV     R7, #1              @ Service command code 1
    SVC     0                   @ Call Linux to terminate