Exercise 1: Tracing COUNTLOOP for the Input "bee" — Possible Solution
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SETUP
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Input "bee" (3 characters), Enter pressed after. Per READLOOP, the
buffer ends up holding ['b', 'e', 'e'] and R3 = 3 characters read.
Entering READDONE, R2 (vowel count) is reset to 0, R4 points back at
the start of BUFFER, and since R3 (3) is nonzero, execution falls
into COUNTLOOP rather than skipping to PRINTRESULT.

PASS-BY-PASS TRACE
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Pass 1 (R3 = 3 remaining):
  R0 <- 'b' (loaded from BUFFER via LDR)
  JSR ISVOWEL -> 'b' matches none of a/e/i/o/u -> R0 returns 0
  R2 = R2 + R0 = 0 + 0 = 0
  R4++, R3-- (R3 becomes 2)
  R2 after this pass: 0

Pass 2 (R3 = 2 remaining):
  R0 <- 'e' (second buffer slot)
  JSR ISVOWEL -> 'e' matches VOWEL_E -> R0 returns 1
  R2 = R2 + R0 = 0 + 1 = 1
  R4++, R3-- (R3 becomes 1)
  R2 after this pass: 1

Pass 3 (R3 = 1 remaining):
  R0 <- 'e' (third buffer slot)
  JSR ISVOWEL -> 'e' matches VOWEL_E again -> R0 returns 1
  R2 = R2 + R0 = 1 + 1 = 2
  R4++, R3-- (R3 becomes 0)
  R2 after this pass: 2

R3 is now 0, so BRp COUNTLOOP does not branch (per assembly1-6, BRp
only branches on a POSITIVE result, and 0 is neither negative nor
positive) — the loop correctly ends here.

FINAL RESULT
------------------------------
R2 = 2 (two vowels found: the two 'e's).

At PRINTRESULT: R0 = R2 + '0' = 2 + 48 = 50, which is the ASCII code
for the character '2'. The program prints "Vowels found: 2" followed
by a newline.

WHY THIS WORKS AS AN ANSWER
------------------------------
It traces R2's value after every single pass through COUNTLOOP rather
than jumping straight to the final answer, correctly identifies which
characters ISVOWEL matches and why, and correctly explains why the
loop terminates after exactly 3 passes (R3 reaching 0, which BRp does
not treat as positive).