1. LMC Tricks Common patterns

2. Single General Purpose Register "Features" – Accumulator only stores most recent value – Add/Subtract look for second value in memory Real world – Processors have multiple registers – Never enough for what you want to do

3. Single General Purpose Register Recipe: – Any time you get a new piece of info, store it Input… store Calculate answer…store – Sometimes you can skip, better safe

4. Order Subtraction must have first operand in accumulator Recipe for X – Y: – Make sure Y is stored in memory – Input/Load X – Subtract Y

5. Branch on Not Zero Want to do things when value is not zero – Use branch to skip code when accumulator = 0 Recipe 1.Do stuff to calculate value 2.Branch if = 0 to step 5 3.Must not be zero, do special stuff here 4.Must not be zero, do special stuff here 5.This happens no matter what

6. Branch on Zero Want to do things when value is zero – Shield always branch with conditional one Recipe: 1.Do stuff to calculate value 2.Branch if = 0 to step 4 3.Branch always to 5 (must not be 0) 4.Special stuff only do with positive value 5.Always do this

7. Repeat Branch to an earlier point causes loop Recipe to repeat while a value >= 0: 1.Do one time setup work 2.… 3.Do stuff to calculate new value 4.… 5.Branch if >= 0 to step 3 (Are we still >= 0? If so repeat) 6. We are done!