/*
 * Based on:
 * https://os.mbed.com/users/kirchnet/code/Nucleo_vs_Arduino_Speed_Test/
 *
 * This is the same whetstone code with adjustments for the
 * Serial.print function on the Arduino
 * The main loop within the procedure whetstone() is identical.
 * Only the output format is Arduino-specific.
 */
int whetstone(void);

void setup() {
  Serial.begin(115200);
  Serial.println("Starting Whetstone benchmark...");
}

void loop() {
  whetstone();
}

/*
 * Source: http://www.netlib.org/benchmark/whetstonec
 *
 * C Converted Whetstone Double Precision Benchmark
 *      Version 1.2 22 March 1998
 *
 *  (c) Copyright 1998 Painter Engineering, Inc.
 *      All Rights Reserved.
 *
 *      Permission is granted to use, duplicate, and
 *      publish this text and program as long as it
 *      includes this entire comment block and limited
 *      rights reference.
 *
 * Converted by Rich Painter, Painter Engineering, Inc. based on the
 * www.netlib.org benchmark/whetstoned version obtained 16 March 1998.
 *
 * A novel approach was used here to keep the look and feel of the
 * FORTRAN version.  Altering the FORTRAN-based array indices,
 * starting at element 1, to start at element 0 for C, would require
 * numerous changes, including decrementing the variable indices by 1.
 * Instead, the array E1[] was declared 1 element larger in C.  This
 * allows the FORTRAN index range to function without any literal or
 * variable indices changes.  The array element E1[0] is simply never
 * used and does not alter the benchmark results.
 *
 * The major FORTRAN comment blocks were retained to minimize
 * differences between versions.  Modules N5 and N12, like in the
 * FORTRAN version, have been eliminated here.
 *
 * An optional command-line argument has been provided [-c] to
 * offer continuous repetition of the entire benchmark.
 * An optional argument for setting an alternate LOOP count is also
 * provided.  Define PRINTOUT to cause the POUT() function to print
 * outputs at various stages.  Final timing measurements should be
 * made with the PRINTOUT undefined.
 *
 * Questions and comments may be directed to the author at
 *          r.painter@ieee.org
 */
/*
C**********************************************************************
C     Benchmark #2 -- Double  Precision Whetstone (A001)
C
C     o This is a REAL*8 version of
C   the Whetstone benchmark program.
C
C     o DO-loop semantics are ANSI-66 compatible.
C
C     o Final measurements are to be made with all
C   WRITE statements and FORMAT sttements removed.
C
C**********************************************************************
*/

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
/* the following is optional depending on the timing function used */
#include <time.h>

/* map the FORTRAN math functions, etc. to the C versions */
#define DSIN    sin
#define DCOS    cos
#define DATAN   atan
#define DLOG    log
#define DEXP    exp
#define DSQRT   sqrt
#define IF      if

/* function prototypes */
void POUT(long N, long J, long K, double X1, double X2, double X3, double X4);
void PA(double E[]);
void P0(void);
void P3(double X, double Y, double *Z);
#define USAGE   "usage: whetdc [-c] [loops]\n"
//#define PRINTOUT

/*
    COMMON T,T1,T2,E1(4),J,K,L
*/
double T,T1,T2,E1[5];
int J,K,L;

int
whetstone(void)
{
    /* used in the FORTRAN version */
    long I;
    long N1, N2, N3, N4, N6, N7, N8, N9, N10, N11;
    double X1,X2,X3,X4,X,Y,Z;
    long LOOP;
    int II, JJ;

    /* added for this version */
    long loopstart;
    long startsec, finisec;
    float KIPS;
    int continuous;

    loopstart = 1000;       /* see the note about LOOP below */
    continuous = 0;

LCONT:
/*
C
C   Start benchmark timing at this point.
C
*/
    startsec = millis();

/*
C
C   The actual benchmark starts here.
C
*/
    T  = .499975;
    T1 = 0.50025;
    T2 = 2.0;
/*
C
C   With loopcount LOOP=10, one million Whetstone instructions
C   will be executed in EACH MAJOR LOOP..A MAJOR LOOP IS EXECUTED
C   'II' TIMES TO INCREASE WALL-CLOCK TIMING ACCURACY.
C
    LOOP = 1000;
*/
    LOOP = loopstart;
    II   = 1;

    JJ = 1;

IILOOP:
    N1  = 0;
    N2  = 12 * LOOP;
    N3  = 14 * LOOP;
    N4  = 345 * LOOP;
    N6  = 210 * LOOP;
    N7  = 32 * LOOP;
    N8  = 899 * LOOP;
    N9  = 616 * LOOP;
    N10 = 0;
    N11 = 93 * LOOP;
/*
C
C   Module 1: Simple identifiers
C
*/
    X1  =  1.0;
    X2  = -1.0;
    X3  = -1.0;
    X4  = -1.0;

    for (I = 1; I <= N1; I++) {
        X1 = (X1 + X2 + X3 - X4) * T;
        X2 = (X1 + X2 - X3 + X4) * T;
        X3 = (X1 - X2 + X3 + X4) * T;
        X4 = (-X1+ X2 + X3 + X4) * T;
    }
#ifdef PRINTOUT
    IF (JJ==II)POUT(N1,N1,N1,X1,X2,X3,X4);
#endif

/*
C
C   Module 2: Array elements
C
*/
    E1[1] =  1.0;
    E1[2] = -1.0;
    E1[3] = -1.0;
    E1[4] = -1.0;

    for (I = 1; I <= N2; I++) {
        E1[1] = ( E1[1] + E1[2] + E1[3] - E1[4]) * T;
        E1[2] = ( E1[1] + E1[2] - E1[3] + E1[4]) * T;
        E1[3] = ( E1[1] - E1[2] + E1[3] + E1[4]) * T;
        E1[4] = (-E1[1] + E1[2] + E1[3] + E1[4]) * T;
    }

#ifdef PRINTOUT
    IF (JJ==II)POUT(N2,N3,N2,E1[1],E1[2],E1[3],E1[4]);
#endif

/*
C
C   Module 3: Array as parameter
C
*/
    for (I = 1; I <= N3; I++)
        PA(E1);

#ifdef PRINTOUT
    IF (JJ==II)POUT(N3,N2,N2,E1[1],E1[2],E1[3],E1[4]);
#endif

/*
C
C   Module 4: Conditional jumps
C
*/
    J = 1;
    for (I = 1; I <= N4; I++) {
        if (J == 1)
            J = 2;
        else
            J = 3;

        if (J > 2)
            J = 0;
        else
            J = 1;

        if (J < 1)
            J = 1;
        else
            J = 0;
    }

#ifdef PRINTOUT
    IF (JJ==II)POUT(N4,J,J,X1,X2,X3,X4);
#endif

/*
C
C   Module 5: Omitted
C   Module 6: Integer arithmetic
C
*/

    J = 1;
    K = 2;
    L = 3;

    for (I = 1; I <= N6; I++) {
        J = J * (K-J) * (L-K);
        K = L * K - (L-J) * K;
        L = (L-K) * (K+J);
        E1[L-1] = J + K + L;
        E1[K-1] = J * K * L;
    }

#ifdef PRINTOUT
    IF (JJ==II)POUT(N6,J,K,E1[1],E1[2],E1[3],E1[4]);
#endif

/*
C
C   Module 7: Trigonometric functions
C
*/
    X = 0.5;
    Y = 0.5;

    for (I = 1; I <= N7; I++) {
        X = T * DATAN(T2*DSIN(X)*DCOS(X)/(DCOS(X+Y)+DCOS(X-Y)-1.0));
        Y = T * DATAN(T2*DSIN(Y)*DCOS(Y)/(DCOS(X+Y)+DCOS(X-Y)-1.0));
    }

#ifdef PRINTOUT
    IF (JJ==II)POUT(N7,J,K,X,X,Y,Y);
#endif

/*
C
C   Module 8: Procedure calls
C
*/
    X = 1.0;
    Y = 1.0;
    Z = 1.0;

    for (I = 1; I <= N8; I++)
        P3(X,Y,&Z);

#ifdef PRINTOUT
    IF (JJ==II)POUT(N8,J,K,X,Y,Z,Z);
#endif

/*
C
C   Module 9: Array references
C
*/
    J = 1;
    K = 2;
    L = 3;
    E1[1] = 1.0;
    E1[2] = 2.0;
    E1[3] = 3.0;

    for (I = 1; I <= N9; I++)
        P0();

#ifdef PRINTOUT
    IF (JJ==II)POUT(N9,J,K,E1[1],E1[2],E1[3],E1[4]);
#endif

/*
C
C   Module 10: Integer arithmetic
C
*/
    J = 2;
    K = 3;

    for (I = 1; I <= N10; I++) {
        J = J + K;
        K = J + K;
        J = K - J;
        K = K - J - J;
    }

#ifdef PRINTOUT
    IF (JJ==II)POUT(N10,J,K,X1,X2,X3,X4);
#endif

/*
C
C   Module 11: Standard functions
C
*/
    X = 0.75;

    for (I = 1; I <= N11; I++)
        X = DSQRT(DEXP(DLOG(X)/T1));

#ifdef PRINTOUT
    IF (JJ==II)POUT(N11,J,K,X,X,X,X);
#endif

/*
C
C      THIS IS THE END OF THE MAJOR LOOP.
C
*/
    if (++JJ <= II)
        goto IILOOP;

/*
C
C      Stop benchmark timing at this point.
C
*/
    finisec = millis();

/*
C----------------------------------------------------------------
C      Performance in Whetstone KIP's per second is given by
C
C   (100*LOOP*II)/TIME
C
C      where TIME is in seconds.
C--------------------------------------------------------------------
*/
    Serial.write("\n");
    if (finisec-startsec <= 0) {
        Serial.write("Insufficient duration- Increase the LOOP count\n");
        return(1);
    }

    Serial.print("Loops: ");
    Serial.print(LOOP);
    Serial.print(" Iterations: ");
    Serial.print(II);
    Serial.print(" Duration: ");
    Serial.print(finisec-startsec);
    Serial.println(" millisec.");//Arduino measures time in milliseconds

//    KIPS = (100.0*LOOP*II)/(float)(finisec-startsec);
      KIPS = (100.0*LOOP*II)/(float)(finisec-startsec)*1000;//convert to seconds from milliseconds
    if (KIPS >= 1000.0){
        Serial.print("C Converted Double Precision Whetstones: ");
        Serial.print(KIPS/1000.0);
        Serial.println(" MIPS");
    }
    else{
        Serial.print("C Converted Double Precision Whetstones: ");
        Serial.print(KIPS);
        Serial.println(" KIPS");
    }

    if (continuous)
        goto LCONT;

    return(0);
}

void
PA(double E[])
{
    J = 0;

L10:
    E[1] = ( E[1] + E[2] + E[3] - E[4]) * T;
    E[2] = ( E[1] + E[2] - E[3] + E[4]) * T;
    E[3] = ( E[1] - E[2] + E[3] + E[4]) * T;
    E[4] = (-E[1] + E[2] + E[3] + E[4]) / T2;
    J += 1;

    if (J < 6)
        goto L10;
}

void
P0(void)
{
    E1[J] = E1[K];
    E1[K] = E1[L];
    E1[L] = E1[J];
}

void
P3(double X, double Y, double *Z)
{
    double X1, Y1;

    X1 = X;
    Y1 = Y;
    X1 = T * (X1 + Y1);
    Y1 = T * (X1 + Y1);
    *Z  = (X1 + Y1) / T2;
}

#ifdef PRINTOUT
void
POUT(long N, long J, long K, double X1, double X2, double X3, double X4)
{
   //sprintf("%7ld %7ld %7ld %12.4e %12.4e %12.4e %12.4e\n",
   //                     N, J, K, X1, X2, X3, X4);
   Serial.print(N);
   Serial.print("\t");
   Serial.print(J);
   Serial.print("\t");
   Serial.print(K);
   Serial.print("\t");
   Serial.print(X1);
   Serial.print("\t");
   Serial.print(X2);
   Serial.print("\t");
   Serial.print(X3);
   Serial.print("\t");
   Serial.print(X4);
   Serial.print("\t");
   Serial.println(N);
}
#endif