tidy up

zk/CPU_architecture.md

@@ -71,10 +71,10 @@ cycle_.
 
 The clock's circuitry is based on a quartz crystal system like that used in
 watches. At precisely timed intervals, the clock sends out pulses of electricity
-that cause bits to move from place to place within
-[logic gates](/zk/Logic_gates.md) or between logic gates and
-[registers](./CPU_architecture.md). This is covered in greater detail in the
-discussion of [clock signals in digital circuits](Clock_signals.md).
+that cause bits to move from place to place within [logic gates](Logic_gates.md)
+or between logic gates and [registers](CPU_architecture.md). This is covered in
+greater detail in the discussion of
+[clock signals in digital circuits](Clock_signals.md).
 
 Simple instructions such as add can often be executed in just one clock cycle,
 whilst complex operations such as divide will require a number of smaller steps,