## Convert space-separated decimal numbers to binary

        ## You know, I think this is almost the same as the i386
        ## system call interface, but maybe with different registers?
        ## Also, different system call numbers!  On i386 %eax=1 is
        ## _exit().
        
	.globl _start
        ## First, read a byte:
_start: xor %edi, %edi          # fd 0
        mov $buf, %esi          # into buf
	xor %edx, %edx
        inc %edx                # 1 byte
        xor %eax, %eax          # _NR_read is 0
        syscall

        test %eax, %eax         # quit if error or EOF
        jle done

        ## Only if we’ve got a space, write out the number:
	mov (buf), %eax
        cmp $32, %eax
        jne keep_converting

        ## We got a space, so we should write out our byte:
        mov %ebx, (buf)         # store byte into buf
	xor %edi, %edi
        inc %edi                # fd 1
        mov $buf, %esi          # write from buf
        mov %edi, %edx          # 1 byte
        mov %edi, %eax          # _NR_write is 1
        syscall

        ## Then repeat:
	xor %ebx, %ebx          # clear accumulating number
        jmp _start

keep_converting:
        imul $10, %ebx
	mov (buf), %eax
        and $15, %eax
        add %eax, %ebx
        jmp _start

        ## Got EOF or error, so exit.
done:   xor %edx, %edx
        mov $231, %eax          # _NR_exit_group in unistd_64.h
        syscall
        
        .data
        .align 8
buf:    .byte 0
        .byte 0
        .byte 0
        .byte 0

        .byte 0
        .byte 0
        .byte 0
        .byte 0