.sh

bash
#!/bin/bash

Define constants
MEMORY_SIZE=1024
PROGRAM_COUNTER=0
ACCUMULATOR=0

Initialize memory
declare -a MEMORY
for ((i=0; i<$MEMORY_SIZE; i++)); do
  MEMORY[$i]=0
done

Load program
load_program() {
  local program=("$@")
  for ((i=0; i<${#program[@]}; i++)); do
    MEMORY[$i]=${program[$i]}
  done
}

Execute program
execute_program() {
  while [ $PROGRAM_COUNTER -lt $MEMORY_SIZE ]; do
    instruction=${MEMORY[$PROGRAM_COUNTER]}
    case $instruction in
      1) # ADD
        PROGRAM_COUNTER=$((PROGRAM_COUNTER+1))
        ACCUMULATOR=$((ACCUMULATOR+MEMORY[$PROGRAM_COUNTER]))
        ;;
      2) # SUB
        PROGRAM_COUNTER=$((PROGRAM_COUNTER+1))
        ACCUMULATOR=$((ACCUMULATOR-MEMORY[$PROGRAM_COUNTER]))
        ;;
      3) # HALT
        break
        ;;
      *) # Unknown instruction
        echo "Unknown instruction: $instruction"
        exit 1
        ;;
    esac
    PROGRAM_COUNTER=$((PROGRAM_COUNTER+1))
  done
}

Reset VM
reset_vm() {
  PROGRAM_COUNTER=0
  ACCUMULATOR=0
  for ((i=0; i<$MEMORY_SIZE; i++)); do
    MEMORY[$i]=0
  done
}

Example program: ADD 5, SUB 3, HALT
program=(1 5 2 3 3)

Load and execute program
load_program "${program[@]}"
execute_program

Print result
echo "Accumulator: $ACCUMULATOR"

Reset VM
reset_vm