ARM: Efficient C for ARM: Taking a Variable’s Address

by David Thomas on

Taking a Variable’s Address

int N;

getlimit(&N);
for (i = 0; i < N; i++)
  ...

Taking the address of a variable means that it must live in memory.

  • The variable is then subject to pointer aliasing.
  • Heavy use of the variable will be costly.

Solution:

  • Make a second, non-memory-bound, copy of the variable for intensive use.

Remarks

When you take the address of a variable it is then memory-bound for its lifetime. So even if, as in this example, you only take the address once then use it later it’s still a memory-bound variable.

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