SimCom

SimCom has 18 instructions
  (Assembler equivalents in brackets)
  and 100 memory boxes (00 to 99).

 0 halt (HLT)
 2 return from subroutine (RTS)
 3 load the accumulator with the next box's contents (LDA #)
 5 add the next box's contents to the accumulator (ADD #)
 6 subtract the next box's contents from the accumulator (SUB #)
 1AA input a number from the keyboard into box AA (INP)
 2AA output the number in box AA (OUT)
 3AA copy the number in box AA into the accumulator (LDA)
 4AA copy the number in the accumulator to box AA (STA)

 5AA add box AA's contents to the accumulator (ADD)
 6AA subtract box AA's contents from the accumulator (SUB)
 7AA jump to box AA (JMP)
 8AA jump to the subroutine starting at box AA (JSR)
 9AA branch to box AA if the accumulator < 0 (BMI)
10AA branch to box AA if the accumulator = 0 (BEQ)
11AA branch to box AA if the accumulator >= 0 (BPL)
12AA add one to box AA (INC)
13AA subtract one from box AA (DEC)