/*

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

  Name: duff

  Author: Jakob Engblom

  Function: Duff's device

  Source: MRTC
          http://www.mrtc.mdh.se/projects/wcet/wcet_bench/duff/duff.c

  Changes: no major functional changes

  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);

void duff_copy(char *to, char *from, int count);
void duff_initialize(char *arr, int length);
void duff_init();
__attribute__((noinline)) __attribute__((export_name("entrypoint"))) void
duff_main(void);
int duff_return(void);
__attribute__((noinline)) __attribute__((export_name("main"))) int main(void);

/*
  Declaration of global variables
*/

char duff_source[100];
char duff_target[100];

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

void
duff_init() {
    unsigned int i;
    unsigned char *p;
    volatile char bitmask = 0;

    duff_initialize(duff_source, 100);

    /*
      Apply volatile XOR-bitmask to entire input array.
    */
    p = (unsigned char *) &duff_source[0];
    __pragma_loopbound(400, 400);
    for (i = 0; i < sizeof(duff_source); ++i, ++p)
        *p ^= bitmask;
}

int
duff_return(void) {
    return (duff_target[28] - 72 != 0);
}

/*
  Algorithm core functions
*/

void
duff_initialize(char *arr, int length) {
    int i;

    __pragma_loopbound(100, 100);
    for (i = 0; i < length; i++)
        arr[i] = length - i;
}

void
duff_copy(char *to, char *from, int count) {
    int n = (count + 7) / 8;

    _Pragma("marker outside") switch (count % 8) {
    case 0:
        do {
            *to++ = *from++;
        case 7:
            *to++ = *from++;
        case 6:
            *to++ = *from++;
        case 5:
            *to++ = *from++;
        case 4:
            *to++ = *from++;
        case 3:
            *to++ = *from++;
        case 2:
            *to++ = *from++;
        case 1:
            _Pragma("marker inside") *to++ = *from++;

        } while (--n > 0);
    }
    _Pragma("flowrestriction 1*inside <= 6*outside")
}

/*
  Main functions
*/

__attribute__((noinline)) __attribute__((export_name("entrypoint"))) void
duff_main(void) {
    duff_copy(duff_target, duff_source, 43);
}

__attribute__((noinline)) __attribute__((export_name("main"))) int
main(void) {
    duff_init();
    duff_main();

    return (duff_return());
}