How to do multiplication and then addition in Marie simulator

Question

Iam new in Marie simulator. I know how to add in the simulator, but unfortunately I don't know how to multiply. for example how can I put a code for this: S=x*Y+z Thanks in advance

Answer 1

You can implement Multiplication using repeated addition.

Here is a basic algorithm.

For positive integers use the algorithm:
    Result = Result - Multiplier
    Multiplicand = Multiplicand - 1
For negative integers use the algorithm:
    Result = Result + Multiplier
    Multiplicand = Multiplicand + 1

In pseudocode:

while Multiplicand != 0
    if Multiplicand > 0
        Result = Result - Multiplier
        Multiplicand = Multiplicand - 1
    else
        Result = Result + Multiplier
        Multiplicand = Multiplicand + 1

This requires two variables to hold the Multiplier and Multiplicand. Additionally you can convert this into a general purpose routine with the JNS (Jump-and-Store instruction) and JUMPI (Jump Indirect).

JNS Multiply

/ Somewhere else
/ Define Multiply as a variable
/ JNS will store the current HEX address
/ in Multiply and start executing the next
/ line

Multiply, DEC 0

/ *** Multiply Body *** /

/ Lastly use JUMPI to Jump Indirectly
/ back to where Multiply was
/ executed from

JUMPI Multiply