/*

  This program is part of the TACLeBench benchmark suite.
  Version V 2.0

  Name: iir

  Author: Juan Martinez Velarde

  Function:
    The equations of each biquad section filter are:
      w(n) =    x(n) - ai1*w(n-1) - ai2*w(n-2)
      y(n) = b0*w(n) + bi1*w(n-1) + bi2*w(n-2)

    Biquads are sequentally positioned. Input sample for biquad i is
    xi-1(n). Output sample for biquad i is xi(n).
    System input sample is x0(n). System output sample is xN(n) = y(n)
    for N biquads.

    Each section performs following filtering (biquad i) :

                              wi(n)
      xi-1(n) ---(-)---------->-|->---bi0---(+)-------> xi(n)
                  A             |            A
                  |           |1/z|          |
                  |             | wi(n-1)    |
                  |             v            |
                  |-<--ai1----<-|->---bi1-->-|
                  |             |            |
                  |           |1/z|          |
                  |             | wi(n-2)    |
                  |             v            |
                  |-<--ai2----<--->---bi2-->-|

    The values wi(n-1) and wi(n-2) are stored in wi1 and wi2

  Source: DSPstone
          http://www.ice.rwth-aachen.de/research/tools-projects/entry/detail/dspstone

  Original name: iir_N_sections_float

  Changes:
           24-03-94 creation fixed-point (Martinez Velarde)
           16-03-95 adaption floating-point (Harald L. Schraut)

  License: may be used, modified, and re-distributed freely

*/

/*
  Forward declaration of functions
*/

// Wasm loop bounds




__attribute__((import_module("__pragma"), import_name("loopbound"))) extern void
__pragma_loopbound(unsigned int min_bound, unsigned int max_bound);

__attribute__((always_inline)) static inline void iir_init(void);
__attribute__((always_inline)) static inline int iir_return(void);
__attribute__((noinline)) __attribute__((export_name("entrypoint")))
__attribute__((noinline)) __attribute__((export_name("entrypoint"))) void
iir_main(void);
__attribute__((noinline)) __attribute__((export_name("main")))
__attribute__((noinline)) __attribute__((export_name("main"))) int
main(void);

/*
  Declaration of global variables
*/

volatile float iir_wi[2 * 4];
volatile float iir_coefficients[5 * 4];
float iir_x;

/*
  Initialization- and return-value-related functions
*/

__attribute__((always_inline)) static inline void
iir_init(void) {
    int f;
    unsigned int i;
    unsigned char *p;
    volatile char bitmask = 0;

    __pragma_loopbound(20, 20);
    for (f = 0; f < 5 * 4; f++)
        iir_coefficients[f] = 7;

    __pragma_loopbound(8, 8);
    for (f = 0; f < 2 * 4; f++)
        iir_wi[f] = 0;

    iir_x = (float) 1;

    /*
      Apply volatile XOR-bitmask to entire input array.
    */
    p = (unsigned char *) &iir_coefficients[0];
    __pragma_loopbound(80, 80);
    for (i = 0; i < sizeof(iir_coefficients); ++i, ++p)
        *p ^= bitmask;

    p = (unsigned char *) &iir_wi[0];
    __pragma_loopbound(32, 32);
    for (i = 0; i < sizeof(iir_wi); ++i, ++p)
        *p ^= bitmask;
}

__attribute__((always_inline)) static inline int
iir_return(void) {
    float checksum = 0.0;
    int f;

    __pragma_loopbound(8, 8);
    for (f = 0; f < 2 * 4; f++)
        checksum += iir_wi[f];

    return ((int) checksum);
}

/*
  Main functions
*/

__attribute__((noinline)) __attribute__((export_name("entrypoint")))
__attribute__((noinline)) __attribute__((export_name("entrypoint"))) void
iir_main(void) {
    register float w;
    int f;
    register volatile float *ptr_coeff, *ptr_wi1, *ptr_wi2;
    register float y;

    ptr_coeff = &iir_coefficients[0];
    ptr_wi1 = &iir_wi[0];
    ptr_wi2 = &iir_wi[1];

    y = iir_x;

    __pragma_loopbound(4, 4);
    for (f = 0; f < 4; f++) {
        w = y - *ptr_coeff++ * *ptr_wi1;
        w -= *ptr_coeff++ * *ptr_wi2;

        y = *ptr_coeff++ * w;
        y += *ptr_coeff++ * *ptr_wi1;
        y += *ptr_coeff++ * *ptr_wi2;

        *ptr_wi2++ = *ptr_wi1;
        *ptr_wi1++ = w;

        ptr_wi2++;
        ptr_wi1++;
    }
}

__attribute__((noinline)) __attribute__((export_name("main")))
__attribute__((noinline)) __attribute__((export_name("main"))) int
main(void) {
    iir_init();
    iir_main();

    return (iir_return() - 400 != 0);
}