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      1 /*
      2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #ifndef VPX_PORTS_MEM_OPS_H_
     12 #define VPX_PORTS_MEM_OPS_H_
     13 
     14 /* \file
     15  * \brief Provides portable memory access primitives
     16  *
     17  * This function provides portable primitives for getting and setting of
     18  * signed and unsigned integers in 16, 24, and 32 bit sizes. The operations
     19  * can be performed on unaligned data regardless of hardware support for
     20  * unaligned accesses.
     21  *
     22  * The type used to pass the integral values may be changed by defining
     23  * MEM_VALUE_T with the appropriate type. The type given must be an integral
     24  * numeric type.
     25  *
     26  * The actual functions instantiated have the MEM_VALUE_T type name pasted
     27  * on to the symbol name. This allows the developer to instantiate these
     28  * operations for multiple types within the same translation unit. This is
     29  * of somewhat questionable utility, but the capability exists nonetheless.
     30  * Users not making use of this functionality should call the functions
     31  * without the type name appended, and the preprocessor will take care of
     32  * it.
     33  *
     34  * NOTE: This code is not supported on platforms where char > 1 octet ATM.
     35  */
     36 
     37 #ifndef MAU_T
     38 /* Minimum Access Unit for this target */
     39 #define MAU_T unsigned char
     40 #endif
     41 
     42 #ifndef MEM_VALUE_T
     43 #define MEM_VALUE_T int
     44 #endif
     45 
     46 #undef MEM_VALUE_T_SZ_BITS
     47 #define MEM_VALUE_T_SZ_BITS (sizeof(MEM_VALUE_T) << 3)
     48 
     49 #undef  mem_ops_wrap_symbol
     50 #define mem_ops_wrap_symbol(fn) mem_ops_wrap_symbol2(fn, MEM_VALUE_T)
     51 #undef  mem_ops_wrap_symbol2
     52 #define mem_ops_wrap_symbol2(fn,typ) mem_ops_wrap_symbol3(fn,typ)
     53 #undef  mem_ops_wrap_symbol3
     54 #define mem_ops_wrap_symbol3(fn,typ) fn##_as_##typ
     55 
     56 /*
     57  * Include aligned access routines
     58  */
     59 #define INCLUDED_BY_MEM_OPS_H
     60 #include "mem_ops_aligned.h"
     61 #undef  INCLUDED_BY_MEM_OPS_H
     62 
     63 #undef  mem_get_be16
     64 #define mem_get_be16 mem_ops_wrap_symbol(mem_get_be16)
     65 static unsigned MEM_VALUE_T mem_get_be16(const void *vmem) {
     66   unsigned MEM_VALUE_T  val;
     67   const MAU_T          *mem = (const MAU_T *)vmem;
     68 
     69   val = mem[0] << 8;
     70   val |= mem[1];
     71   return val;
     72 }
     73 
     74 #undef  mem_get_be24
     75 #define mem_get_be24 mem_ops_wrap_symbol(mem_get_be24)
     76 static unsigned MEM_VALUE_T mem_get_be24(const void *vmem) {
     77   unsigned MEM_VALUE_T  val;
     78   const MAU_T          *mem = (const MAU_T *)vmem;
     79 
     80   val = mem[0] << 16;
     81   val |= mem[1] << 8;
     82   val |= mem[2];
     83   return val;
     84 }
     85 
     86 #undef  mem_get_be32
     87 #define mem_get_be32 mem_ops_wrap_symbol(mem_get_be32)
     88 static unsigned MEM_VALUE_T mem_get_be32(const void *vmem) {
     89   unsigned MEM_VALUE_T  val;
     90   const MAU_T          *mem = (const MAU_T *)vmem;
     91 
     92   val = mem[0] << 24;
     93   val |= mem[1] << 16;
     94   val |= mem[2] << 8;
     95   val |= mem[3];
     96   return val;
     97 }
     98 
     99 #undef  mem_get_le16
    100 #define mem_get_le16 mem_ops_wrap_symbol(mem_get_le16)
    101 static unsigned MEM_VALUE_T mem_get_le16(const void *vmem) {
    102   unsigned MEM_VALUE_T  val;
    103   const MAU_T          *mem = (const MAU_T *)vmem;
    104 
    105   val = mem[1] << 8;
    106   val |= mem[0];
    107   return val;
    108 }
    109 
    110 #undef  mem_get_le24
    111 #define mem_get_le24 mem_ops_wrap_symbol(mem_get_le24)
    112 static unsigned MEM_VALUE_T mem_get_le24(const void *vmem) {
    113   unsigned MEM_VALUE_T  val;
    114   const MAU_T          *mem = (const MAU_T *)vmem;
    115 
    116   val = mem[2] << 16;
    117   val |= mem[1] << 8;
    118   val |= mem[0];
    119   return val;
    120 }
    121 
    122 #undef  mem_get_le32
    123 #define mem_get_le32 mem_ops_wrap_symbol(mem_get_le32)
    124 static unsigned MEM_VALUE_T mem_get_le32(const void *vmem) {
    125   unsigned MEM_VALUE_T  val;
    126   const MAU_T          *mem = (const MAU_T *)vmem;
    127 
    128   val = mem[3] << 24;
    129   val |= mem[2] << 16;
    130   val |= mem[1] << 8;
    131   val |= mem[0];
    132   return val;
    133 }
    134 
    135 #define mem_get_s_generic(end,sz) \
    136   static signed MEM_VALUE_T mem_get_s##end##sz(const void *vmem) {\
    137     const MAU_T *mem = (const MAU_T*)vmem;\
    138     signed MEM_VALUE_T val = mem_get_##end##sz(mem);\
    139     return (val << (MEM_VALUE_T_SZ_BITS - sz)) >> (MEM_VALUE_T_SZ_BITS - sz);\
    140   }
    141 
    142 #undef  mem_get_sbe16
    143 #define mem_get_sbe16 mem_ops_wrap_symbol(mem_get_sbe16)
    144 mem_get_s_generic(be, 16)
    145 
    146 #undef  mem_get_sbe24
    147 #define mem_get_sbe24 mem_ops_wrap_symbol(mem_get_sbe24)
    148 mem_get_s_generic(be, 24)
    149 
    150 #undef  mem_get_sbe32
    151 #define mem_get_sbe32 mem_ops_wrap_symbol(mem_get_sbe32)
    152 mem_get_s_generic(be, 32)
    153 
    154 #undef  mem_get_sle16
    155 #define mem_get_sle16 mem_ops_wrap_symbol(mem_get_sle16)
    156 mem_get_s_generic(le, 16)
    157 
    158 #undef  mem_get_sle24
    159 #define mem_get_sle24 mem_ops_wrap_symbol(mem_get_sle24)
    160 mem_get_s_generic(le, 24)
    161 
    162 #undef  mem_get_sle32
    163 #define mem_get_sle32 mem_ops_wrap_symbol(mem_get_sle32)
    164 mem_get_s_generic(le, 32)
    165 
    166 #undef  mem_put_be16
    167 #define mem_put_be16 mem_ops_wrap_symbol(mem_put_be16)
    168 static void mem_put_be16(void *vmem, MEM_VALUE_T val) {
    169   MAU_T *mem = (MAU_T *)vmem;
    170 
    171   mem[0] = (val >> 8) & 0xff;
    172   mem[1] = (val >> 0) & 0xff;
    173 }
    174 
    175 #undef  mem_put_be24
    176 #define mem_put_be24 mem_ops_wrap_symbol(mem_put_be24)
    177 static void mem_put_be24(void *vmem, MEM_VALUE_T val) {
    178   MAU_T *mem = (MAU_T *)vmem;
    179 
    180   mem[0] = (val >> 16) & 0xff;
    181   mem[1] = (val >>  8) & 0xff;
    182   mem[2] = (val >>  0) & 0xff;
    183 }
    184 
    185 #undef  mem_put_be32
    186 #define mem_put_be32 mem_ops_wrap_symbol(mem_put_be32)
    187 static void mem_put_be32(void *vmem, MEM_VALUE_T val) {
    188   MAU_T *mem = (MAU_T *)vmem;
    189 
    190   mem[0] = (val >> 24) & 0xff;
    191   mem[1] = (val >> 16) & 0xff;
    192   mem[2] = (val >>  8) & 0xff;
    193   mem[3] = (val >>  0) & 0xff;
    194 }
    195 
    196 #undef  mem_put_le16
    197 #define mem_put_le16 mem_ops_wrap_symbol(mem_put_le16)
    198 static void mem_put_le16(void *vmem, MEM_VALUE_T val) {
    199   MAU_T *mem = (MAU_T *)vmem;
    200 
    201   mem[0] = (val >>  0) & 0xff;
    202   mem[1] = (val >>  8) & 0xff;
    203 }
    204 
    205 #undef  mem_put_le24
    206 #define mem_put_le24 mem_ops_wrap_symbol(mem_put_le24)
    207 static void mem_put_le24(void *vmem, MEM_VALUE_T val) {
    208   MAU_T *mem = (MAU_T *)vmem;
    209 
    210   mem[0] = (val >>  0) & 0xff;
    211   mem[1] = (val >>  8) & 0xff;
    212   mem[2] = (val >> 16) & 0xff;
    213 }
    214 
    215 #undef  mem_put_le32
    216 #define mem_put_le32 mem_ops_wrap_symbol(mem_put_le32)
    217 static void mem_put_le32(void *vmem, MEM_VALUE_T val) {
    218   MAU_T *mem = (MAU_T *)vmem;
    219 
    220   mem[0] = (val >>  0) & 0xff;
    221   mem[1] = (val >>  8) & 0xff;
    222   mem[2] = (val >> 16) & 0xff;
    223   mem[3] = (val >> 24) & 0xff;
    224 }
    225 
    226 #endif  // VPX_PORTS_MEM_OPS_H_
    227