Exercise 1: Tracing sum_array for [1, 2, 1, 3, 1] — Possible Solution
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SETUP
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Array: [1, 2, 1, 3, 1] (indices 0-4)
Entering the loop: RAX = 0 (sum), RCX = 0 (index), RSI = 5 (count)

ITERATION-BY-ITERATION TRACE
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RCX=0: CMP RCX,RSI -> 0 != 5, continue.
       RAX += array[0] (=1) -> RAX = 0 + 1 = 1
       INC RCX -> RCX = 1

RCX=1: CMP RCX,RSI -> 1 != 5, continue.
       RAX += array[1] (=2) -> RAX = 1 + 2 = 3
       INC RCX -> RCX = 2

RCX=2: CMP RCX,RSI -> 2 != 5, continue.
       RAX += array[2] (=1) -> RAX = 3 + 1 = 4
       INC RCX -> RCX = 3

RCX=3: CMP RCX,RSI -> 3 != 5, continue.
       RAX += array[3] (=3) -> RAX = 4 + 3 = 7
       INC RCX -> RCX = 4

RCX=4: CMP RCX,RSI -> 4 != 5, continue.
       RAX += array[4] (=1) -> RAX = 7 + 1 = 8
       INC RCX -> RCX = 5

RCX=5: CMP RCX,RSI -> 5 == 5 -> JE .done taken. Loop ends.

FINAL SUM
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RAX = 8 when sum_array returns.

CONVERTING TO ASCII
------------------------------
Back in _start: ADD AL, '0' computes 8 + 0x30 (the ASCII code for '0')
= 0x38, which is the ASCII code for the character '8'. This byte is
stored into outbuf[0].

FINAL OUTPUT
------------------------------
The program writes outbuf's two bytes (the character '8', followed by
the newline byte already sitting at outbuf[1]) to stdout, printing:

8
(followed by a newline)

WHY THIS WORKS AS AN ANSWER
------------------------------
It traces RAX and RCX through every single iteration individually
rather than jumping to the final total, correctly identifies the
exact iteration (RCX=5) where the loop-ending comparison succeeds,
and correctly converts the final sum into its resulting ASCII
character and full printed output.