none/tests/ppc32/mftocrf.c

   1
   2 #include <stdio.h>
   3 #include <config.h>
   4
   5 static
   6 int try_mtocrf ( int x )
   7 {
   8   int base = 0x31415927;
   9   int res;
  10 #ifdef HAVE_AS_PPC_MFTOCRF
  11   /* pre-set CR */
  12   __asm__ __volatile__(
  13      "mtcr %0"
  14      : /*w*/ : /*r*/ "b"(base) : /*trash*/"cc" );
  15
  16   /* do it */
  17   __asm__ __volatile__(
  18      "mtocrf 4, %0"
  19      : /*w*/ : /*r*/ "b"(x) : /*trash*/"cc" );
  20
  21   /* get CR */
  22   __asm__ __volatile__(
  23      "mfcr %0"
  24      : /*w*/"=b"(res) : /*r*/ );
  25 #else
  26   res = 42;
  27 #endif
  28   return res;
  29 }
  30
  31 static
  32 int try_mfocrf ( int x )
  33 {
  34    int res;
  35 #ifdef HAVE_AS_PPC_MFTOCRF
  36    /* CR = x */
  37    __asm__ __volatile__(
  38      "mtcr %0"
  39      : /*w*/ : /*r*/ "b"(x) : /*trash*/"cc" );
  40
  41   /* do it */
  42   __asm__ __volatile__(
  43      "li %0,0\n\t"
  44      "mfocrf %0,64"
  45      : /*w*/"=b"(res) : /*r*/ );
  46 #else
  47   res = 42;
  48 #endif
  49   return res;
  50 }
  51
  52 /* This is a bit of a kludge since mfocrf reads the spec'd CR field,
  53    but the remaining returned bits are undefined.  It seems like on
  54    MPC7447A (Apple Mac Mini) mfocrf just reads the entire CR, which is
  55    an acceptable implementation, but is not necessarily what other
  56    implementations are going to do. */
  57
  58 int main ( void )
  59 {
  60   int i, j;
  61   for (i = 0; i < 32; i++) {
  62     printf("0x%08x\n", try_mtocrf( 1<<i ));
  63   }
  64   printf("\n");
  65   j = 1;
  66   for (i = 0; i < 32; i++) {
  67     printf("0x%08x\n", try_mfocrf( j ));
  68     j *= 3;
  69   }
  70
  71   return 0;
  72 }