basic instructions
arithmetic operations
- add R1 R2
add the contents of R1 and R2 and put the result in R1
- sub R1 R2
load instructions
- load R1 R2
overwrite contents of register R1 with contents of register R2
- load R1 #3
load the constant 3 into register R1
- load R1 4(R2)
load the contents of the memory address obtained by adding 4 to the address in R2
into the register R1