5.128 · exercise

Predict: command-line arguments

Work out what argc, the argv entries, strlen and atoi give for the command line each question names.

0 of 5 correct

main:
        mov     w19, w0
        mov     x20, x1

The program is started as ./program "big cat" dog. What value does w19 hold? Answer in decimal.

main:
        ldr     x0, [x1, 8]
        bl      strlen

The program is started as ./program "big cat" dog. What value does x0 hold after strlen returns? Answer in decimal.

main:
        ldr     x0, [x1, 8]
        bl      atoi

The program is started as ./program 042. What value does w0 hold after atoi returns? Answer in decimal.

main:
        ldr     x20, [x1, 16]
        ldrb    w21, [x20, 1]

The program is started as ./program red blue. What value does w21 hold? Answer in decimal.

main:
        ldr     x22, [x1, w0, sxtw 3]

The program is started as ./program a b c. What value does x22 hold? Answer in decimal.