AOC2019day9part2

9.sh

#!/bin/bash -eu

declare -ai program ram
declare -i addrmode1 addrmode2 arg1 arg2 pc=0 rb=0
IFS=, read -r -a program < "$1"
shift
inputs=("$@")
ram=("${program[@]}")
ops=(x '+' '*' x x '-eq' '-ne' '<' '==')
while : ; do
  printf -v opcode %05d "${ram[pc++]}"
  case "${opcode: -2:2}" in
    01|02|07|08) addrmode1=${opcode: -3:1} addrmode2=${opcode: -4:1} arg1=${ram[pc++]} arg2=${ram[pc++]} ram[(${opcode: -5:1} != 0)*rb+${ram[pc++]}]=$(((addrmode1 == 1 ? arg1 : ram[(addrmode1 != 0)*rb+arg1]) ${ops[${opcode: -1:1}]} (addrmode2 == 1 ? arg2 : ram[(addrmode2 != 0)*rb+arg2]))) ;;
    03)
      ram[(${opcode: -3:1} == 0 ? 0 : rb)+${ram[pc++]}]=${inputs[0]}
      inputs=("${inputs[*]:1}")
      ;;
    04)
      addrmode1=${opcode: -3:1} arg1=${ram[pc++]}
      echo $((addrmode1 == 1 ? arg1 : ram[(addrmode1 == 0 ? 0 : rb)+arg1]))
      ;;
    05|06)
      addrmode1=${opcode: -3:1} addrmode2=${opcode: -4:1} arg1=${ram[pc++]} arg2=${ram[pc++]}
      [ "$((addrmode1 == 1 ? arg1 : ram[(addrmode1 == 0 ? 0 : rb)+arg1]))" ${ops[${opcode: -1:1}]} 0 ] || pc=$((addrmode2 == 1 ? arg2 : ram[(addrmode2 == 0 ? 0 : rb)+arg2]))
      ;;
    09)
      addrmode1=${opcode: -3:1} arg1=${ram[pc++]}
      ((rb+=addrmode1 == 1 ? arg1 : ram[(addrmode1 == 0 ? 0 : rb)+arg1]))
      ;;
    99) break ;;
  esac
done