Example
x = a - b + c - d;
- sub $10, $4,$5
- sub $11, $6,$7
- add $12,$10,$11
- 0 4 5 10 0 34
- 0 6 7 11 0 34
- 0 10 11 12 0 32
- 000000 00100 00101 01010 00000 100010
- 000000 00110 00111 01011 00000 100010
- 000000 01010 01011 01100 00000 100000
Assumes that somehow a,b,c,d correspond to $4,$5,$6,$7