gdb/rdi-share/bytesex.c

   1 /*
   2  * Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved.
   3  *
   4  * This software may be freely used, copied, modified, and distributed
   5  * provided that the above copyright notice is preserved in all copies of the
   6  * software.
   7  */
   8
   9 /*
  10  * bytesex.c - Code to support byte-sex independence
  11  * Copyright: (C) 1991, Advanced RISC Machines Ltd., Cambridge, England.
  12  */
  13
  14 /*
  15  * RCS $Revision$
  16  * Checkin $Date$
  17  */
  18
  19 #include "bytesex.h"
  20
  21 static int reversing_bytes = 0;
  22
  23 void bytesex_reverse(yes_or_no)
  24 int yes_or_no;
  25 { reversing_bytes = yes_or_no;
  26 }
  27
  28 int bytesex_reversing()
  29 {
  30   return reversing_bytes;
  31 }
  32
  33 int32 bytesex_hostval(v)
  34 int32 v;
  35 { /* Return v with the same endian-ness as the host */
  36   /* This mess generates better ARM code than the more obvious mess */
  37   /* and may eventually peephole to optimal code...                 */
  38   if (reversing_bytes)
  39   { unsigned32 t;
  40     /* t = v ^ (v ror 16) */
  41     t = v ^ ((v << 16) | (((unsigned32)v) >> 16));
  42     t &= ~0xff0000;
  43     /* v = v ror 8 */
  44     v = (v << 24) | (((unsigned32)v) >> 8);
  45     v = v ^ (t >> 8);
  46   }
  47   return v;
  48 }
  49
  50 int32 bytesex_hostval_16(v)
  51 int32 v;
  52 {
  53   if (reversing_bytes) {
  54     v = ((v >> 8) & 0xff) | ((v << 8) & 0xff00);
  55   }
  56   return v;
  57 }