created: 07/18/01; edits: 10/20/01, 02/22/03, 06/26/03, 07/06/15
power of computers
is their ability to repeat actions
and their ability to alter their operation
depending on data.
Modern programming languages express
these abilities using control structures.
Repeated action (iteration) is done with a
Alternative control paths (alternation) is done with an
The machine instructions of the processor do not have these structures, nor does assembly language. When you program in assembly language you must build these structures out of basic assembly instructions. These basic instructions are the jump instructions and the conditional branch instructions.
beqinstruction (branch equal)
bneinstruction (branch not equal)
When a program is executing, does each machine instruction have an address in main memory?