PIPPIN Project 3

This program computes y = 2x

[0]   LOD #1        ; ACC=1
[2]   STO Y         ; Y=1

[4]   CPZ X         ; X=0 ?
[6]   JMZ #10       ; NO, proceed
[8]   HLT           ; YES, stop

[10]  LOD Y         ; ACC=Y
[12]  MUL #2        ; ACC=Y*2
[14]  STO Y         ; p = Y*2

[16]  LOD X         ; ACC=X
[18]  SUB #1        ; ACC=X-1
[20]  STO X         ; X = X-1
[22]  JMP #4        ; jump to instruction in cell [4]

[X]   4             ; storage for x
[Y]   0             ; storage for y

For a comparison, the same task in JavaScript for computing y = 2x for x = 4 could look as follows:

var X = 4;
var Y = 1;

while (X != 0)
{
  Y = Y * 2;
  X = X - 1;
}