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    "# Assembly Language\n",
    "\n",
    "## Fibonacci \n",
    "\n",
    "For the Little Computer 3\n",
    "\n"
   ]
  },
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   "cell_type": "code",
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    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "============================================================\n",
      "Memory disassembled:\n",
      "============================================================\n",
      "           x3000: x260D  LD R3, N_VAL                              [line: 1]\n",
      "LOOP:      x3001: x0407  BRz DONE (or 7)                           [line: 2]\n",
      "           x3002: x2009  LD R0, I_VAL                              [line: 3]\n",
      "           x3003: x2209  LD R1, J_VAL                              [line: 4]\n",
      "           x3004: x1401  ADD R2, R0, R1                            [line: 6]\n",
      "           x3005: x3206  ST R1, I_VAL                              [line: 8]\n",
      "           x3006: x3406  ST R2, J_VAL                              [line: 9]\n",
      "           x3007: x16FF  ADD R3, R3, #-1                           [line: 11]\n",
      "           x3008: x0FF8  BRnzp LOOP                                [line: 12]\n",
      "DONE:      x3009: x3401  ST R2, RESULT                             [line: 14]\n",
      "           x300A: xF025  HALT                                      [line: 16]\n",
      "RESULT:    x300B: x0000  NOOP - (no BR to I_VAL) (or 0)            [line: 17]\n",
      "I_VAL:     x300C: x0001  NOOP - (no BR to N_VAL) (or 1)            [line: 18]\n",
      "J_VAL:     x300D: x0000  NOOP - (no BR to N_VAL) (or 0)            [line: 19]\n",
      "N_VAL:     x300E: x0014  NOOP - (no BR to x3023) (or 20)           [line: 20]\n",
      "\n",
      "============================================================\n",
      "Registers:\n",
      "============================================================\n",
      "PC: x300F\n",
      "N: 0 Z: 1 P: 0 \n",
      "R0: x0000 R1: x0000 R2: x0000 R3: x0000 \n",
      "R4: x0000 R5: x0000 R6: x0000 R7: x0000 \n"
     ]
    }
   ],
   "source": [
    "        .ORIG x3000 \n",
    "        LD R3, N_VAL\n",
    "Loop    BRz Done ; check if last operation flagged z-bit\n",
    "        LD R0, I_VAL ; load i\n",
    "        LD R1, J_VAL ; load j\n",
    "\n",
    "        ADD R2, R0, R1 ; t = i + j\n",
    "\n",
    "        ST R1, I_VAL ; j = i (R1)\n",
    "        ST R2, J_VAL ; j = t (R2)\n",
    "\n",
    "        ADD R3, R3, -1 ; count down n\n",
    "        BR Loop\n",
    "\n",
    "Done    ST R2, RESULT ; Result in R2\n",
    " \n",
    "        HALT\n",
    "RESULT  .FILL x0000 \n",
    "I_VAL   .FILL x0001\n",
    "J_VAL   .FILL x0000\n",
    "N_VAL   .FILL 20 ; n -> fib(n) fib(20) = #6765  = x1A6D\n",
    "        .END \n",
    "        "
   ]
  },
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   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "============================================================\n",
      "Computation completed\n",
      "============================================================\n",
      "Instructions: 164\n",
      "Cycles: 1274 (0.000637 milliseconds)\n",
      "\n",
      "============================================================\n",
      "Registers:\n",
      "============================================================\n",
      "PC: x048E\n",
      "N: 0 Z: 1 P: 0 \n",
      "R0: x0A18 R1: x1055 R2: x1A6D R3: x0000 \n",
      "R4: x0000 R5: x0000 R6: x0000 R7: x300B \n"
     ]
    }
   ],
   "source": [
    "%exe"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "6765\n",
      "6765\n"
     ]
    }
   ],
   "source": [
    "%%python\n",
    "\n",
    "print(0x1A6D)\n",
    "\n",
    "def fib(n):\n",
    "    if n < 3:\n",
    "        return 1\n",
    "    else:\n",
    "        return fib(n - 1) + fib(n - 2)\n",
    "    \n",
    "print(fib(20))"
   ]
  },
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   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
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