/*
 * test-adder.c
 * ------------
 * This program tests the Novena EIM interface by repeatedly writing
 * two 32-bit values to the FPGA, and reading back the sum.
 *
 * Author: Pavel Shatov
 * Copyright (c) 2015, NORDUnet A/S All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the NORDUnet nor the names of its contributors may
 *   be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


//------------------------------------------------------------------------------
// Headers
//------------------------------------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

#include "novena-eim.h"


//------------------------------------------------------------------------------
// Demo Adder
//------------------------------------------------------------------------------
#define DEMO_ADDER_BASE_ADDR    (0x3210)
#define DEMO_ADDER_REG_X        (EIM_BASE_ADDR + DEMO_ADDER_BASE_ADDR + (0<<2))
#define DEMO_ADDER_REG_Y        (EIM_BASE_ADDR + DEMO_ADDER_BASE_ADDR + (1<<2))
#define DEMO_ADDER_REG_Z        (EIM_BASE_ADDR + DEMO_ADDER_BASE_ADDR + (2<<2))
#define DEMO_ADDER_REG_SC       (EIM_BASE_ADDR + DEMO_ADDER_BASE_ADDR + (3<<2))


//------------------------------------------------------------------------------
// Prototypes
//------------------------------------------------------------------------------
uint32_t    demo_adder_test_round   (uint32_t, uint32_t);
uint32_t    lfsr_next_x             (uint32_t);
uint32_t    lfsr_next_y             (uint32_t);


//------------------------------------------------------------------------------
// Testing Parameters
//------------------------------------------------------------------------------
const int   NUM_TEST_ROUNDS     = 10000;
const int   PRINT_XYZ_VALUES    = 1;


//------------------------------------------------------------------------------
int main(void)
//------------------------------------------------------------------------------
{
    int i;
    uint32_t x = 0x12341234, y = 0xABCDABCD, zyx;

    // try to setup eim (return value should be 1)
    printf("Configuring EIM .. ");
    if (eim_setup() < 1) {
        printf("ERROR\n");
        return EXIT_FAILURE;
    }
    else
        printf("OK\n");

    // run test
    printf("Testing started.\n");
    for (i=0; i<NUM_TEST_ROUNDS; i++) {
        // run another round
        uint32_t z = demo_adder_test_round(x, y);

        // calculate correct answer
        zyx = x + y;

        // check result
        if (z != zyx) {
            printf("ERROR: round %10d of %10d: x == 0x%08X, y == 0x%08X, "
                   "z == 0x%08X [z should be 0x%08X]\n",
                   i+1, NUM_TEST_ROUNDS, x, y, z, zyx);
            exit(EXIT_FAILURE);
        }
        else if (PRINT_XYZ_VALUES)
            printf("OK: round %10d of %10d: x == 0x%08X, y == 0x%08X, "
                   "z == 0x%08X\n", i+1, NUM_TEST_ROUNDS, x, y, z);

        // update input values
        x = lfsr_next_x(x);
        y = lfsr_next_x(y);
    }

    // ok
    printf("Testing completed successfully.\n");

    // done
    return EXIT_SUCCESS;
}


//------------------------------------------------------------------------------
uint32_t demo_adder_test_round(uint32_t x, uint32_t y)
//------------------------------------------------------------------------------
{
    uint32_t ctl;
    uint32_t sts;
    uint32_t z;

    // write x
    eim_write_32(DEMO_ADDER_REG_X, &x);

    // write y
    eim_write_32(DEMO_ADDER_REG_Y, &y);

    /* To make adder calculate something we need to change its control
     * register, so we read it, increment and write back. Control register is
     * in the lower 16 bits.
     */
    eim_read_32(DEMO_ADDER_REG_SC, &ctl);
    ctl += 1;
    ctl &= 0x0000FFFF;
    eim_write_32(DEMO_ADDER_REG_SC, &ctl);

    /* When adder is done, it will write new control value into its status
     * register. Adder has 1-cycle latency which is very small, we don't even
     * need to poll, just check that status was updated. Status register is in
     * the upper 16 bits.
     */
    eim_read_32(DEMO_ADDER_REG_SC, &sts);
    sts >>= 16;
    if (sts != ctl)
    {   printf("ERROR: Adder timeout!\n");
        exit(EXIT_FAILURE);
    }

    // read z
    eim_read_32(DEMO_ADDER_REG_Z, &z);

    // uncomment to trigger an error
    //z++;

    // done
    return z;
}


//------------------------------------------------------------------------------
uint32_t lfsr_next_x(uint32_t value)
//------------------------------------------------------------------------------
{
    //
    // [32, 31, 29, 28, 27, 25, 24, 23, 21, 19, 17, 14, 10, 6, 4, 2]
    //   0   1   3   4   5   7   8   9  11  13  15  18  22 24 28 30
    //

    uint32_t carry = 0;

    carry ^= (value >>  0);
    carry ^= (value >>  1);
    carry ^= (value >>  3);
    carry ^= (value >>  4);

    carry ^= (value >>  5);
    carry ^= (value >>  7);
    carry ^= (value >>  8);
    carry ^= (value >>  9);

    carry ^= (value >> 11);
    carry ^= (value >> 13);
    carry ^= (value >> 15);
    carry ^= (value >> 18);

    carry ^= (value >> 22);
    carry ^= (value >> 24);
    carry ^= (value >> 28);
    carry ^= (value >> 30);

    value >>= 1, value |= (carry << 31);

    return value;
}


//------------------------------------------------------------------------------
uint32_t lfsr_next_y(uint32_t value)
//------------------------------------------------------------------------------
{
    //
    // [32, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 1]
    //   0  15  16  17  18  19  20  21  22 23 24 25 26 27 28 31
    //

    uint32_t carry = 0;

    carry ^= (value >>  0);
    carry ^= (value >> 15);
    carry ^= (value >> 16);
    carry ^= (value >> 17);

    carry ^= (value >> 18);
    carry ^= (value >> 19);
    carry ^= (value >> 20);
    carry ^= (value >> 21);

    carry ^= (value >> 22);
    carry ^= (value >> 23);
    carry ^= (value >> 24);
    carry ^= (value >> 25);

    carry ^= (value >> 26);
    carry ^= (value >> 27);
    carry ^= (value >> 28);
    carry ^= (value >> 31);

    value >>= 1, value |= (carry << 31);

    return value;
}



//------------------------------------------------------------------------------
// End-of-File
//------------------------------------------------------------------------------