#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>

#include <libmcpu.h>


static int failures = 0;

#define CHECK(cond,msg) \
  do { \
    if( !(cond) ) \
    { \
      fprintf( stderr, "FAIL: %s\n", (msg) ); \
      ++failures; \
    } \
  } while( 0 )


int
main( void )
{
  __mpu_UNIT_t *r64;
  __mpu_UNIT_t *r32_0;
  __mpu_UNIT_t *r32_4;
  __mpu_UNIT_t *r16_2;
  __mpu_UNIT_t *r8_3;
  unsigned int i;

  __cpu_init();

  r64   = __cpu_reg_ptr( 64, 0 );
  r32_0 = __cpu_reg_ptr( 32, 0 );
  r32_4 = __cpu_reg_ptr( 32, 4 );
  r16_2 = __cpu_reg_ptr( 16, 2 );
  r8_3  = __cpu_reg_ptr(  8, 3 );

  CHECK( r64   != 0, "r64@0 pointer" );
  CHECK( r32_0 != 0, "r32@0 pointer" );
  CHECK( r32_4 != 0, "r32@4 pointer" );
  CHECK( r16_2 != 0, "r16@2 pointer" );
  CHECK( r8_3  != 0, "r8@3 pointer" );

  CHECK( r64 == r32_0, "r64@0 and r32@0 start at same byte" );
  CHECK( r32_4 == r64 + 4, "r32@4 overlaps upper four bytes of r64@0" );
  CHECK( r16_2 == r64 + 2, "r16@2 overlaps bytes 2..3 of r64@0" );
  CHECK( r8_3 == r64 + 3, "r8@3 overlaps byte 3 of r64@0" );

  for( i = 0; i < 8; ++i ) r64[i] = (__mpu_UNIT_t)( 0x10 + i );

  CHECK( r32_0[0] == 0x10 && r32_0[1] == 0x11 &&
         r32_0[2] == 0x12 && r32_0[3] == 0x13,
         "r32@0 sees bytes written through r64@0" );

  CHECK( r32_4[0] == 0x14 && r32_4[1] == 0x15 &&
         r32_4[2] == 0x16 && r32_4[3] == 0x17,
         "r32@4 sees bytes written through r64@0" );

  CHECK( r16_2[0] == 0x12 && r16_2[1] == 0x13,
         "r16@2 sees bytes written through r64@0" );

  *r8_3 = 0xa5;
  CHECK( r64[3] == 0xa5,
         "write through r8@3 changes r64@0 storage" );
  CHECK( r32_0[3] == 0xa5,
         "write through r8@3 changes r32@0 storage" );
  CHECK( r16_2[1] == 0xa5,
         "write through r8@3 changes r16@2 storage" );

  /* Check the same property at a non-zero naturally aligned address. */
  {
    __mpu_UNIT_t *r128 = __cpu_reg_ptr( 128, 0x00100 );
    __mpu_UNIT_t *r32  = __cpu_reg_ptr(  32, 0x0010c );
    __mpu_UNIT_t *r8   = __cpu_reg_ptr(   8, 0x0010f );

    CHECK( r128 != 0 && r32 != 0 && r8 != 0,
           "overlap pointers at 0x00100" );
    CHECK( r32 == r128 + 12,
           "r32@0x0010c inside r128@0x00100" );
    CHECK( r8 == r128 + 15,
           "r8@0x0010f inside r128@0x00100" );

    r128[15] = 0x5a;
    CHECK( *r8 == 0x5a,
           "r8 view sees r128 storage" );

    r32[3] = 0xc3;
    CHECK( r128[15] == 0xc3,
           "r32 view changes r128 storage" );
  }

  if( failures != 0 )
  {
    fprintf( stderr, "libcpu overlap regression: %d failure(s)\n", failures );
    return( 1 );
  }

  printf( "libcpu 0.0.3 overlapping register views regression: PASS\n" );
  printf( "overlap is byte-storage aliasing and is endian independent\n" );

  return( 0 );
}