#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>

#include "speed_stats.h"

#define D_FLOP_ITERS    1
#define I_OP_ITERS      1
#define BANDWIDTH_ITERS 1

//#define RUN_TEST

#ifdef RUN_TEST

int main( void ) {
    int cache_size;
    
    cache_size = check_cache_size( CACHE_MAX );
    
    run_test_suite( 4 );
    
    return 0;
}

#endif

int check_cache_size( int mem_size ) {
    int i, n, index, stride, *memBlock, logStride, logCache;
    double **results;
    int steps, tsteps, csize, limit, temp, cind, sind;
    clock_t total_sec, sec;
    double secs, nanosecs, temp2;
    int not_found;
    
    logStride = (int)(log(STRIDE_MAX/STRIDE_MIN)/log(2))+1;
    logCache = (int)(log(CACHE_MAX/CACHE_MIN)/log(2))+1;
    
    printf( "Test will take about %.2f seconds.\n", SECS_PER_RUN*logStride*logCache );
    results = (double **)malloc( sizeof( double * )*logStride );
    
    for( i=0;i<logStride;i++ ) {
        results[i] = (double *)malloc( sizeof( double )*logCache );
        for( n=0;n<logCache;n++ ) {
            results[i][n] = 1.0;
        }
    }
    
    printf( "|" );
    for( i=0;i<logCache;i++ ) {
        printf( "-" );
    }
    
    printf( "|\n" );
    memBlock = (int *)malloc( sizeof( int )*mem_size );
    printf( " " );
    
    for( csize=CACHE_MIN,cind=0;csize<=CACHE_MAX;csize*=2,cind++ ) {
        for (stride = STRIDE_MIN,sind=0; stride<=STRIDE_MAX; stride*=2,sind++ ) {
            limit = csize - stride + 1;                // cache size this loop

            steps = 0;
            sec = clock();
            do {                            // repeat until collect 1 second
                for (i = SAMPLE * stride; i != 0; i-- )    {    // larger sample
                    for (index = 0; index < limit; index += stride) {
                        memBlock[index]++;                // cache access
                    }
                }
                steps++;                    // count while loop iterations
            } while (clock() < sec+(CLOCKS_PER_SEC*SECS_PER_RUN));    // until collect 1 second
            total_sec = clock()-sec;

            // Repeat empty loop to loop subtract overhead
            tsteps = 0;                        // used to match no. while iterations
            temp = 0;
            sec = clock();
            do {                            // repeat until same no. iterations as above
                for (i = SAMPLE * stride; i != 0; i-- )    {    // larger sample
                    for (index = 0; index < limit; index += stride) {
                        temp += index;                // dummy code
                    }
                }
                tsteps++;                    // count while iterations
            } while (tsteps < steps);                    // until = no. iterations
            total_sec -= clock()-sec;
            
            secs = ((double)total_sec) / CLOCKS_PER_SEC;
            
            if( temp == 3 ) {
                printf( "Howdy\n" );
            }
            
            nanosecs = (double) secs * 1e9 / (steps * SAMPLE * stride * ((limit - 1) / stride + 1));
            results[sind][cind] = nanosecs;
            
            //if( stride==STRIDE_MIN ) printf("\n");
            printf(
                "Size (bytes): %7d Stride (bytes): %4d read+write: %4.0f ns, %d %d\n",
                csize * sizeof (int), stride * sizeof( int ), nanosecs, sind, cind
            );
        }
        printf( "." );
        fflush( stdout );
    }
    printf( "\n" );
    
    for( i=0;i<logStride;i++ ) {
        for( n=0;n<logCache;n++ ) {
            printf ("%4.0f ", results[i][n]);
        }
        printf( "\n" );
    }
    
    for( i=0;i<logStride;i++ ) {
        for( n=logCache;n>0;n-- ) {
            results[i][n] /= results[i][n-1];
        }
    }
    
    for( i=0;i<logCache;i++ ) {
        temp2 = 0;
        for( n=0;n<logStride;n++ ) {
            temp2 += results[n][i];
        }
        results[0][i] = temp2/logStride;
    }
    
    printf( "\n" );
    for( i=0;i<logStride;i++ ) {
        for( n=1;n<logCache;n++ ) {
            printf ("%1.3f ", results[i][n]);
        }
        printf( "\n" );
    }
    
    csize=CACHE_MIN;
    i = 1;
    not_found = 2;
    while( not_found && i < logCache ) {
        if( not_found == 1 && results[0][i] > 1.5 ) {
            printf( "Level 2 Data Cache is %d KB.\n", csize*sizeof(int)/CACHE_MIN );
            not_found = 0;
        }
        if( not_found == 2 && results[0][i] > 1.5 ) {
            printf( "Level 1 Data Cache is %d KB.\n", csize*sizeof(int)/CACHE_MIN );
            not_found = 1;
        }
        i++;
        csize *= 2;
    }
    
    free( memBlock );
    for( i=0;i<logStride;i++ )
        free( results[i] );
    
    free( results );
    
    return 0;
}

double run_double_prec_test( double num_secs ) {
    int df_test_time, df_iters;
    double df_secs;
    
    // Start by doing some quick timing tests for rough calibration
    df_test_time = (int)double_flop_test( D_FLOP_ITERS, 0 );
    if( df_test_time <= 0 ) df_test_time = 1;
    df_secs = (double)df_test_time/CLOCKS_PER_SEC;

    // Calculate the # of iterations based on these tests
    df_iters = (int)(D_FLOP_ITERS*num_secs/df_secs);

    if( df_iters > D_FLOP_ITERS )  {    // no need to redo test
        df_test_time = (int)double_flop_test( df_iters, 0 );
    } else {
        df_iters = D_FLOP_ITERS;
    }
        
    df_secs = (double)df_test_time/CLOCKS_PER_SEC;
    
    return 1000000*df_iters/df_secs;
}

double run_int_test( double num_secs ) {
    int int_test_time, int_iters;
    double int_secs;

    // Start by doing some quick timing tests for rough calibration
    int_test_time = (int)int_op_test( I_OP_ITERS, 0 );
    if( int_test_time <= 0 ) int_test_time = 1;
    int_secs = (double)int_test_time/CLOCKS_PER_SEC;

    // Calculate the # of iterations based on these tests
    int_iters = (int)(I_OP_ITERS*num_secs/int_secs);

    if( int_iters > I_OP_ITERS )  { // no need to redo test
        int_test_time = (int)int_op_test( int_iters, 0 );
    } else {
        int_iters = I_OP_ITERS;
    }
    
    int_secs = (double)int_test_time/CLOCKS_PER_SEC;
    
    return 1000000*int_iters/int_secs;
}

double run_mem_bandwidth_test( double num_secs ) {
    int bw_test_time;
    double bw_secs;
    int bw_iters;

    // Start by doing some quick timing tests for rough calibration
    bw_test_time = (int)bandwidth_test( BANDWIDTH_ITERS, 0 );
    if( bw_test_time <= 0 ) bw_test_time = 1;
    bw_secs = (double)bw_test_time/CLOCKS_PER_SEC;
    
    // Calculate the # of iterations based on these tests
    bw_iters = (int)(BANDWIDTH_ITERS*num_secs/bw_secs);
    
    if( bw_iters > BANDWIDTH_ITERS )  { // no need to redo test
        bw_test_time = (int)bandwidth_test( bw_iters, 0 );
    } else {
        bw_iters = BANDWIDTH_ITERS;
    }

    bw_secs = (double)bw_test_time/CLOCKS_PER_SEC;
    return 1000000*bw_iters/bw_secs;
}

void run_test_suite( double num_secs_per_test ) {
    printf(
        "Running tests.  This will take about %.1lf seconds.\n\n",
        num_secs_per_test*3
    );
    
    printf(
        "Speed: %.5lf million flops/sec\n\n",
        run_double_prec_test(num_secs_per_test)/1000000
    );
    printf(
        "Speed: %.5lf million integer ops/sec\n\n",
        run_int_test(num_secs_per_test)/1000000
    );
    printf(
        "Speed: %.5lf MB/sec\n\n",
        12*sizeof(double)*run_mem_bandwidth_test(num_secs_per_test)/1000000
    );
}

// One iteration == D_LOOP_ITERS (1,000,000) floating point operations

clock_t double_flop_test( int iterations, int print_debug ) {
    double a[NUM_DOUBLES],t1,t2;
    double temp;
    clock_t time_start, time_total;
    int i,j,k,calc_error;
    
    // Initialize the array
    a[0] = 1;
    for( i=1;i<NUM_DOUBLES;i++ )
        a[i] = a[i-1]/2.0;
    
    // Ideally, the array "a" will fit into cache, meaning this test doesn't
    // really include memory accesses
    time_start = clock();
    for( i=0;i<iterations;i++ ) {
        for( j=0;j<D_LOOP_ITERS;j+=((NUM_DOUBLES-1)*5) ) {
            temp = 1;
            t1 = a[0];
            // These tests do a pretty good job of breaking the processor pipeline,
            // since the result from all but one of the lines is required for the
            // next line.
           
            for( k=0;k<NUM_DOUBLES-1;k++ ) {
                t2 = a[k+1];
                t1 = t1 * t2;            // 1st FLOP
                temp = temp + temp;       // 2nd FLOP
                t1 = t1 * temp;          // 3rd FLOP
                t1 = t1 + t2;            // 4th FLOP
                t1 = t1 / 1.5;           // 5th FLOP
                a[k] = t1;
                t1 = t2;
            }
        }
    }
    
    time_total = clock()-time_start;
    
    calc_error = 0;
    temp = 1;
    // Check to make sure all the values are the same
    for( i=0;i<NUM_DOUBLES;i++ ) {
        if( (float)a[i] != (float)temp ) {
            calc_error = 1;
        }
        
        temp /= 3;
    }
    
    if( calc_error ) printf( "Calc error\n" );
    
    if( print_debug ) {
        for( i=0;i<NUM_DOUBLES;i++ ) {
            printf( "%3d: %.50lf\n", i, a[i] );
        }
    }
    
    return time_total;
}

// One iteration == 1,000,000 integer operations

clock_t int_op_test( int iterations, int print_debug ) {
    int a[NUM_INTS], temp;
    clock_t time_start, time_total;
    int i,j,k,calc_error;

    a[0] = 1;
    for( i=1;i<NUM_INTS;i++ ) {
        a[i] = 2*a[i-1];
    }
    
    time_start = clock();
    for( i=0;i<iterations;i++ ) {
        for( j=0;j<I_LOOP_ITERS/(NUM_INTS*8);j++ ) {
            for( k=0;k<NUM_INTS;k++ ) {
                a[k] *= 3;   // 2 int ops
            }
            for( k=NUM_INTS-1;k>=0;k-- ) {
                a[k] += 6;   // 2 int ops
            }
            for( k=0;k<NUM_INTS;k++ ) {
                a[k] /= 3;   // 2 int ops
            }
            for( k=NUM_INTS-1;k>=0;k-- ) {
                a[k] -= 2;   // 2 int ops
            }
            //for( k=NUM_INTS-1;k>0;k-- ) {
            //    a[k] -= a[k-1];
            //}
            for( k=1;k<NUM_INTS;k++ ) {
                a[k] = 2*a[k-1];
            }
            for( k=NUM_INTS-1;k>0;k-- ) {
                a[k] /= a[k-1];
            }
            a[0] /= 2;
            for( k=1;k<NUM_INTS;k++ ) {
                a[k] = 2*a[k-1];
            }
        }
    }

    time_total = clock()-time_start;
    
    calc_error = 0;
    temp = 1;
    // Check to make sure all the values are the same
    for( i=0;i<NUM_INTS;i++ ) {
        if( a[i] != temp ) {
            calc_error = 1;
        }
        
        temp *= 2;
    }
    
    if( calc_error )
        printf( "Calc error\n" );
    
    if( print_debug ) {
        for( i=0;i<NUM_INTS;i++ ) {
            printf( "%3d: %d\n", i, a[i] );
        }
    }
    
    return time_total;
}

// One iteration == Read of 6M*sizeof(double), Write of 6M*sizeof(double)

clock_t bandwidth_test( int iterations, int print_debug ) {
    // a, b, and c are arrays of doubles we will copy around to test memory bandwidth
    double *a, *b, *c;
    // aVal and bVal are the values of all elements of a and b.
    // These values use every other bit,
    // so that if there is a HW problem it will easily manifest itself

    double aVal, bVal;
    // Start and stop times for the clock
    clock_t time_start, time_total;
    int i,j,copy_error;

    // These are doubles in order to make full use of bus and instruction bandwidth
    a = (double *)malloc( MEM_SIZE * sizeof( double ) );
    b = (double *)malloc( MEM_SIZE * sizeof( double ) );
    c = (double *)malloc( MEM_SIZE * sizeof( double ) );
    
    // These values use all the bits in a floating point number (Investigate these values)
    aVal = (-2.0/3.0)*pow(2.0,-341.0);
    bVal = (1.0/3.0)*pow(2.0,342.0);
    
    // We add i to each value to prevent compiler optimizations of the copy
    for( i=0;i<MEM_SIZE;i++ ) {
        a[i] = aVal+i; b[i] = bVal+i; c[i] = 1.0;
    }
    
    // Start the clock
    time_start = clock();
    
    // 6 read, 6 write operations per iteration which will preserve a and b
    for( i=0;i<iterations*2;i++ ) {
        for( j=0;j<MEM_SIZE;j++ ) {
            c[j] = a[j];
            a[j] = b[j];
            b[j] = c[j];
        }
    }

    // Stop the clock
    time_total = clock();
    
    // Accomodate for the possibility of clock wraparound
    if( time_total > time_start ) {
        time_total -= time_start;
    } else {
        time_total -= time_start;
    }
    
    copy_error = 0;
    for( i=0;i<MEM_SIZE;i++ ) {
        if( a[i] != aVal+i || b[i] != bVal+i ) {
            copy_error = 1;
        }
    }
    
    if( copy_error ) {
        printf( "Copy error\n" );
    }
    
    free( a );
    free( b );
    free( c );
    
    return time_total;
}