Arty Dozenal Calculator

#include "PmodKYPD.h"
#include "sleep.h"
#include "xil_cache.h"
#include "xil_io.h"
#include "xparameters.h"

#define PMODKYPD_BASEADDR XPAR_PMODKYPD_0_AXI_LITE_GPIO_BASEADDR
#define BTN_BASEADDR      XPAR_AXI_GPIO_0_BASEADDR

#define KYPD_KEYTABLE "0*/-789+456E123X"

#define READ_BTN Xil_In8(BTN_BASEADDR)

#define MAX_LENGTH 32

char parseInput(char *input, int *operand1, int *operand2);
int  dozToDec(char digit);
int  decToDoz(char *result, int num);
int  isOperator(char ch);
int  evaluate(int op1, int op2, char operator);
void enableCaches();
void disableCaches();

PmodKYPD keypad;

int main() {
   enableCaches();

   print("Begin\n\n\r");

   KYPD_begin(&keypad, PMODKYPD_BASEADDR);
   KYPD_loadKeyTable(&keypad, (u8*) KYPD_KEYTABLE);

   u16 keystate;
   XStatus status, lastStatus = KYPD_NO_KEY;
   u8 key, lastKey = 'z';

   Xil_Out32(keypad.GPIO_addr, 0xF);
   char input[MAX_LENGTH];
   u8 btn = READ_BTN;
   while (1) {
      int i = 0;
      while (btn == 0) {
         keystate = KYPD_getKeyStates(&keypad);
         status = KYPD_getKeyPressed(&keypad, keystate, &key);
         if (status == KYPD_SINGLE_KEY
               && (status != lastStatus || key != lastKey)) {
            input[i] = key;
            xil_printf("%c", key);
            lastKey = key;
            i++;
         }
         lastStatus = status;
         usleep(1000);
         btn = READ_BTN;
      }
      for(; i < MAX_LENGTH; i++) {
         input[i] = '\0';
      }
      if (btn == 8) {
         break;
      }
      while (btn) {
         btn = READ_BTN; // Wait for button to be released
      }
      int op1, op2;
      char operator = parseInput(input, &op1, &op2);
      int resultDec = evaluate(op1, op2, operator);
      char resultDoz[MAX_LENGTH];
      int isNegative = decToDoz(resultDoz, resultDec);
      print("\n\r            = ");
      if (isNegative) {
         print("-");
      }
      xil_printf("%s\n\r", resultDoz);
   }
   print("\n\rDone\n\r");

   disableCaches();
   return 0;
}

char parseInput(char *input, int *operand1, int *operand2) {
   int op1 = 0;
   int op2 = 0;
   char operator;
   int operatorFound = 0;
   int i = 0;
   while (input[i] != '\0' && i < MAX_LENGTH) {
      if (!operatorFound) {
         if (isOperator(input[i])) {
            operator = input[i];
            operatorFound = 1;
         } else {
            op1 = op1 * 12 + dozToDec(input[i]);
         }
      } else {
         if (!isOperator(input[i])) {
            op2 = op2 * 12 + dozToDec(input[i]);
         }
      }
      i++;
   }
   *operand1 = op1;
   *operand2 = op2;
   return operator;
}

int dozToDec(char digit) {
   if (digit == 'X') {
      return 10;
   } else if (digit == 'E') {
      return 11;
   } else {
      return (int) (digit - '0');
   }
}

// Return 1 if result is negative
int decToDoz(char *result, int num) {
   int isNegative = num < 0;
   int dozDigits[MAX_LENGTH];
   int i = 0;
   if (num == 0) {
      result[0] = '0';
      result[1] = '\0';
   } else {
      if (isNegative) {
         num *= -1;
      }
      while (num > 0 && i < MAX_LENGTH) {
         dozDigits[i] = num % 12; // Determine value in each dozenal place value
         num /= 12;               // in reverse order
         i++;
      }
      int endIndex = i;
      for (i = 0; i < endIndex; i++) {
         if (dozDigits[endIndex - i - 1] == 10) {
            result[i] = 'X';
         } else if (dozDigits[endIndex - i - 1] == 11) {
            result[i] = 'E';
         } else {
            result[i] = dozDigits[endIndex - i - 1] + '0';
         }
      }
      result[endIndex] = '\0';
   }
   return isNegative;
}

int isOperator(char ch) {
   return ch == '+' || ch == '-' || ch == '*' || ch == '/';
}

int evaluate(int op1, int op2, char operator) {
   if (operator == '+') {
      return op1 + op2;
   } else if (operator == '-') {
      return op1 - op2;
   } else if (operator == '*') {
      return op1 * op2;
   } else if (operator == '/') {
      return op1 / op2;
   } else {
      return 0;
   }
}

void enableCaches() {
#ifdef __MICROBLAZE__
#ifdef XPAR_MICROBLAZE_USE_ICACHE
   Xil_ICacheEnable();
#endif
#ifdef XPAR_MICROBLAZE_USE_DCACHE
   Xil_DCacheEnable();
#endif
#endif
}

void disableCaches() {
#ifdef __MICROBLAZE__
#ifdef XPAR_MICROBLAZE_USE_DCACHE
   Xil_DCacheDisable();
#endif
#ifdef XPAR_MICROBLAZE_USE_ICACHE
   Xil_ICacheDisable();
#endif
#endif
}