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      1 
      2 /*--------------------------------------------------------------------*/
      3 /*--- Asm-only TransTab stuff.             pub_core_transtab_asm.h ---*/
      4 /*--------------------------------------------------------------------*/
      5 
      6 /*
      7    This file is part of Valgrind, a dynamic binary instrumentation
      8    framework.
      9 
     10    Copyright (C) 2000-2010 Julian Seward
     11       jseward (at) acm.org
     12 
     13    This program is free software; you can redistribute it and/or
     14    modify it under the terms of the GNU General Public License as
     15    published by the Free Software Foundation; either version 2 of the
     16    License, or (at your option) any later version.
     17 
     18    This program is distributed in the hope that it will be useful, but
     19    WITHOUT ANY WARRANTY; without even the implied warranty of
     20    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     21    General Public License for more details.
     22 
     23    You should have received a copy of the GNU General Public License
     24    along with this program; if not, write to the Free Software
     25    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
     26    02111-1307, USA.
     27 
     28    The GNU General Public License is contained in the file COPYING.
     29 */
     30 
     31 #ifndef __PUB_CORE_TRANSTAB_ASM_H
     32 #define __PUB_CORE_TRANSTAB_ASM_H
     33 
     34 /* Constants for the fast translation lookup cache.  It is a direct
     35    mapped cache, with 2^VG_TT_FAST_BITS entries.
     36 
     37    On x86/amd64, the cache index is computed as
     38    'address[VG_TT_FAST_BITS-1 : 0]'.
     39 
     40    On ppc32/ppc64, the bottom two bits of instruction addresses are
     41    zero, which means that function causes only 1/4 of the entries to
     42    ever be used.  So instead the function is '(address >>u
     43    2)[VG_TT_FAST_BITS-1 : 0]' on those targets.
     44 
     45    On ARM we do like ppc32/ppc64, although that will have to be
     46    revisited when we come to implement Thumb. */
     47 
     48 #define VG_TT_FAST_BITS 15
     49 #define VG_TT_FAST_SIZE (1 << VG_TT_FAST_BITS)
     50 #define VG_TT_FAST_MASK ((VG_TT_FAST_SIZE) - 1)
     51 
     52 /* This macro isn't usable in asm land; nevertheless this seems
     53    like a good place to put it. */
     54 #if defined(VGA_x86) || defined(VGA_amd64)
     55 #  define VG_TT_FAST_HASH(_addr)  ((((UWord)(_addr))     ) & VG_TT_FAST_MASK)
     56 #elif defined(VGA_ppc32) || defined(VGA_ppc64) || defined(VGA_arm)
     57 #  define VG_TT_FAST_HASH(_addr)  ((((UWord)(_addr)) >> 2) & VG_TT_FAST_MASK)
     58 #else
     59 #  error "VG_TT_FAST_HASH: unknown platform"
     60 #endif
     61 
     62 #endif   // __PUB_CORE_TRANSTAB_ASM_H
     63 
     64 /*--------------------------------------------------------------------*/
     65 /*--- end                                                          ---*/
     66 /*--------------------------------------------------------------------*/
     67