/* test mixed integer and char operations on the Hades MIPS processors.
 *
 * 04.04.06 fnh
 *
 * Note that the compiler will use load-byte and store-byte instructions,
 * which means that the endianness of the processor matters.
 * Our gcc x86-x86-mips-elf (2.7.2.3) crosscompiler uses little-endian 
 * memory accesses, and the MIPS must be configured correspondingly.
 *
 * When successful, the program writes an array of 256 chars (bytes)
 * with values 00,01,02,...,fe,ff starting at memory address 0x*400
 * (Hades MipsRAM internal address 0x00100), and a second array of
 * 256 bytes with values 03,04,05,...,fe,ff,00,01,02 starting at 
 * memory address 0x*600 (internal address 0x00150).
 * The program then tries to read the first array back and checks
 * the values. If successful, the program writes the magic value
 * 0xcafe0000 into memory address 0x*3ff (0x000ff) and enters an endless
 * loop.
 * When the read-back values don't match, the program writes the value
 * 0xdead0000 and enters an endless loop.
 */


#define BASE  0x00000400
#define OK    (BASE- 8)
#define BAD   (BASE- 12)


static char* hello = "Hello, world!\n\f";



void bad( int c ) {
  int i, *bad;
 
  bad= (int*) BAD;
  *(bad-1) = 0xdead0000 + c;
  for( i=0; ; i++ ) {
    *bad= i;
  }
}


int main( int argc, char** argv ) {
 
  char c, d;
  char *ptr, *ptr2;
  int  *ready;
  int  i,j;


  ptr = (char*) (BASE-32);

  *ptr = 'a';
  *(ptr+1) = 'b';
  *(ptr+2) = 'c';
  *(ptr+3) = 'd';

  // *(ptr+4) = 'e';
  *(ptr+5) = 'f';

  d = *(ptr+3);

  ready = (int*) OK;
  *(ready-12) = 0xbabe0000 | d;
  *(ready-11) = 0x000a1234 | d;

  ptr = (char*) BASE;
  ptr2 = (char*) (BASE+256+64);

  // write sequence of ASCII chars
  c = (char) 1;
  for( i=0; i < 256; i++ ) {
    c = (char) i;
    d = (char) (i+3);

    *(ptr+i)  = c;

    *ptr2 = d;
    ptr2++;
  }

  

  // read them back and compare
  ptr = (char*) BASE;
  for( i=0; i < 256; i++ ) {
    c = (*ptr); 
    if (c != (char)i) {
      bad( i );
    }
    ptr++;
  }

  // success: endless loop
  *(ready+1) = 0xcafe0000;
  for( i=0; ; i++ ) {
    *ready = i;
  }
}