5.122 · exercise

Fill in the blank: input and output

Fill in the missing token in calls to scanf and printf, and to the read and write system calls.

0 of 5 correct

The format string's address is already in x0. Pass the address of the .bss slot count_n as scanf's second argument.

ldr , =count_n

Pick the write system call before svc 0.

mov x8,

done_m labels the 5-byte message .ascii "done\n". Let the assembler count its bytes for write, on the line right after it.

done_len = - done_m

A read system call (x8 = 63) is to take up to 16 bytes from standard input. Pick the file descriptor.

mov x0,

Print a long, held in x1, after the word total.

fmt_total: .string "total: %\n"