Exercise 1: Register Assignment for Three Arguments, Both Conventions — Possible Solution
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GIVEN
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A function call with three integer arguments: 100, 200, 300 (in that
order).

SYSTEM V AMD64 ABI (LINUX/MACOS)
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Per this chapter's own register order (RDI, RSI, RDX, RCX, R8, R9):

  1st argument (100) -> RDI
  2nd argument (200) -> RSI
  3rd argument (300) -> RDX

MICROSOFT X64 (WINDOWS)
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Per this chapter's own register order (RCX, RDX, R8, R9):

  1st argument (100) -> RCX
  2nd argument (200) -> RDX
  3rd argument (300) -> R8

WHY THIS WORKS AS AN ANSWER
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It applies each convention's own register ORDER exactly as given in
the chapter's own table, correctly assigning the three arguments to
the first three registers in each list — and correctly shows that the
two conventions assign the SAME argument values to DIFFERENT
registers (for instance, the 2nd argument lands in RSI under System V
but RDX under Microsoft x64), which is the whole point of the
distinction this chapter draws.