Subversion Repositories neorv32

// #################################################################################################

// # << NEORV32 - CFS Demo Program >>                                                              #

// # ********************************************************************************************* #

// # BSD 3-Clause License                                                                          #

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// # Copyright (c) 2022, Stephan Nolting. All rights reserved.                                     #

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// # The NEORV32 Processor - https://github.com/stnolting/neorv32              (c) Stephan Nolting #

// #################################################################################################

/**********************************************************************//**

 * @file demo_cfs/main.c

 * @author Stephan Nolting

 * @brief Simple demo program for the _default_ custom functions subsystem (CFS) module.

 **************************************************************************/

#include <neorv32.h>

/**********************************************************************//**

 * @name User configuration

 **************************************************************************/

/**@{*/

/** UART BAUD rate */

#define BAUD_RATE 19200

/** Number of test cases per CFS function */

#define TESTCASES 4

/**@}*/

/**********************************************************************//**

 * @name Prototypes

 **************************************************************************/

uint32_t xorshift32(void);

/**********************************************************************//**

 * Main function

 *

 * @note This program requires the CFS and UART0.

 *

 * @return 0 if execution was successful

 **************************************************************************/

int main() {

  uint32_t i, tmp;

  // init UART0 at default baud rate, no parity bits, no HW flow control

  neorv32_uart0_setup(BAUD_RATE, PARITY_NONE, FLOW_CONTROL_NONE);

  // capture all exceptions and give debug info via UART0

  // this is not required, but keeps us safe

  neorv32_rte_setup();

  // check if CFS is implemented at all

  if (neorv32_cfs_available() == 0) {

    neorv32_uart0_printf("Error! No CFS synthesized!\n");

    return 1;

  }

  // intro

  neorv32_uart0_printf("<<< NEORV32 Custom Functions Subsystem (CFS) Demo Program >>>\n\n");

  neorv32_uart0_printf("NOTE: This program assumes the _default_ CFS hardware module, which implements\n"

                       "      simple data conversion functions using four memory-mapped registers.\n\n");

  neorv32_uart0_printf("Default CFS memory-mapped registers:\n"

                       " * NEORV32_CFS.REG[0] (r/w): convert binary to gray code\n"

                       " * NEORV32_CFS.REG[1] (r/w): convert gray to binary code\n"

                       " * NEORV32_CFS.REG[2] (r/w): bit reversal\n"

                       " * NEORV32_CFS.REG[3] (r/w): byte swap\n"

                       "The remaining 28 CFS registers are unused and will return 0 when read.\n");

  // function examples

  neorv32_uart0_printf("\n--- CFS 'binary to gray' function ---\n");

  for (i=0; i<TESTCASES; i++) {

    tmp = xorshift32(); // get random test data

    NEORV32_CFS.REG[0] = tmp; // write to CFS memory-mapped register 0

    neorv32_uart0_printf("%u: IN = 0x%x, OUT = 0x%x\n", i, tmp, NEORV32_CFS.REG[0]); // read from CFS memory-mapped register 0

  }

  neorv32_uart0_printf("\n--- CFS 'gray to binary' function ---\n");

  for (i=0; i<TESTCASES; i++) {

    tmp = xorshift32(); // get random test data

    NEORV32_CFS.REG[1] = tmp; // write to CFS memory-mapped register 1

    neorv32_uart0_printf("%u: IN = 0x%x, OUT = 0x%x\n", i, tmp, NEORV32_CFS.REG[1]); // read from CFS memory-mapped register 1

  }

  neorv32_uart0_printf("\n--- CFS 'bit reversal' function ---\n");

  for (i=0; i<TESTCASES; i++) {

    tmp = xorshift32(); // get random test data

    NEORV32_CFS.REG[2] = tmp; // write to CFS memory-mapped register 2

    neorv32_uart0_printf("%u: IN = 0x%x, OUT = 0x%x\n", i, tmp, NEORV32_CFS.REG[2]); // read from CFS memory-mapped register 2

  }

  neorv32_uart0_printf("\n--- CFS 'byte swap' function ---\n");

  for (i=0; i<TESTCASES; i++) {

    tmp = xorshift32(); // get random test data

    NEORV32_CFS.REG[3] = tmp; // write to CFS memory-mapped register 3

    neorv32_uart0_printf("%u: IN = 0x%x, OUT = 0x%x\n", i, tmp, NEORV32_CFS.REG[3]); // read from CFS memory-mapped register 3

  }

  neorv32_uart0_printf("\nCFS demo program completed.\n");

  return 0;

}

/**********************************************************************//**

 * Pseudo-Random Number Generator (to generate deterministic test vectors).

 *

 * @return Random data (32-bit).

 **************************************************************************/

uint32_t xorshift32(void) {

  static uint32_t x32 = 314159265;

  x32 ^= x32 << 13;

  x32 ^= x32 >> 17;

  x32 ^= x32 << 5;

  return x32;

}