michael@0: /*
michael@0:  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
michael@0:  *
michael@0:  *  Use of this source code is governed by a BSD-style license
michael@0:  *  that can be found in the LICENSE file in the root of the source
michael@0:  *  tree. An additional intellectual property rights grant can be found
michael@0:  *  in the file PATENTS.  All contributing project authors may
michael@0:  *  be found in the AUTHORS file in the root of the source tree.
michael@0:  */
michael@0: 
michael@0: 
michael@0: /* \file
michael@0:  * \brief Provides portable memory access primitives
michael@0:  *
michael@0:  * This function provides portable primitives for getting and setting of
michael@0:  * signed and unsigned integers in 16, 24, and 32 bit sizes. The operations
michael@0:  * can be performed on unaligned data regardless of hardware support for
michael@0:  * unaligned accesses.
michael@0:  *
michael@0:  * The type used to pass the integral values may be changed by defining
michael@0:  * MEM_VALUE_T with the appropriate type. The type given must be an integral
michael@0:  * numeric type.
michael@0:  *
michael@0:  * The actual functions instantiated have the MEM_VALUE_T type name pasted
michael@0:  * on to the symbol name. This allows the developer to instantiate these
michael@0:  * operations for multiple types within the same translation unit. This is
michael@0:  * of somewhat questionable utility, but the capability exists nonetheless.
michael@0:  * Users not making use of this functionality should call the functions
michael@0:  * without the type name appended, and the preprocessor will take care of
michael@0:  * it.
michael@0:  *
michael@0:  * NOTE: This code is not supported on platforms where char > 1 octet ATM.
michael@0:  */
michael@0: 
michael@0: #ifndef MAU_T
michael@0: /* Minimum Access Unit for this target */
michael@0: #define MAU_T unsigned char
michael@0: #endif
michael@0: 
michael@0: #ifndef MEM_VALUE_T
michael@0: #define MEM_VALUE_T int
michael@0: #endif
michael@0: 
michael@0: #undef MEM_VALUE_T_SZ_BITS
michael@0: #define MEM_VALUE_T_SZ_BITS (sizeof(MEM_VALUE_T) << 3)
michael@0: 
michael@0: #undef  mem_ops_wrap_symbol
michael@0: #define mem_ops_wrap_symbol(fn) mem_ops_wrap_symbol2(fn, MEM_VALUE_T)
michael@0: #undef  mem_ops_wrap_symbol2
michael@0: #define mem_ops_wrap_symbol2(fn,typ) mem_ops_wrap_symbol3(fn,typ)
michael@0: #undef  mem_ops_wrap_symbol3
michael@0: #define mem_ops_wrap_symbol3(fn,typ) fn##_as_##typ
michael@0: 
michael@0: /*
michael@0:  * Include aligned access routines
michael@0:  */
michael@0: #define INCLUDED_BY_MEM_OPS_H
michael@0: #include "mem_ops_aligned.h"
michael@0: #undef  INCLUDED_BY_MEM_OPS_H
michael@0: 
michael@0: #undef  mem_get_be16
michael@0: #define mem_get_be16 mem_ops_wrap_symbol(mem_get_be16)
michael@0: static unsigned MEM_VALUE_T mem_get_be16(const void *vmem) {
michael@0:   unsigned MEM_VALUE_T  val;
michael@0:   const MAU_T          *mem = (const MAU_T *)vmem;
michael@0: 
michael@0:   val = mem[0] << 8;
michael@0:   val |= mem[1];
michael@0:   return val;
michael@0: }
michael@0: 
michael@0: #undef  mem_get_be24
michael@0: #define mem_get_be24 mem_ops_wrap_symbol(mem_get_be24)
michael@0: static unsigned MEM_VALUE_T mem_get_be24(const void *vmem) {
michael@0:   unsigned MEM_VALUE_T  val;
michael@0:   const MAU_T          *mem = (const MAU_T *)vmem;
michael@0: 
michael@0:   val = mem[0] << 16;
michael@0:   val |= mem[1] << 8;
michael@0:   val |= mem[2];
michael@0:   return val;
michael@0: }
michael@0: 
michael@0: #undef  mem_get_be32
michael@0: #define mem_get_be32 mem_ops_wrap_symbol(mem_get_be32)
michael@0: static unsigned MEM_VALUE_T mem_get_be32(const void *vmem) {
michael@0:   unsigned MEM_VALUE_T  val;
michael@0:   const MAU_T          *mem = (const MAU_T *)vmem;
michael@0: 
michael@0:   val = mem[0] << 24;
michael@0:   val |= mem[1] << 16;
michael@0:   val |= mem[2] << 8;
michael@0:   val |= mem[3];
michael@0:   return val;
michael@0: }
michael@0: 
michael@0: #undef  mem_get_le16
michael@0: #define mem_get_le16 mem_ops_wrap_symbol(mem_get_le16)
michael@0: static unsigned MEM_VALUE_T mem_get_le16(const void *vmem) {
michael@0:   unsigned MEM_VALUE_T  val;
michael@0:   const MAU_T          *mem = (const MAU_T *)vmem;
michael@0: 
michael@0:   val = mem[1] << 8;
michael@0:   val |= mem[0];
michael@0:   return val;
michael@0: }
michael@0: 
michael@0: #undef  mem_get_le24
michael@0: #define mem_get_le24 mem_ops_wrap_symbol(mem_get_le24)
michael@0: static unsigned MEM_VALUE_T mem_get_le24(const void *vmem) {
michael@0:   unsigned MEM_VALUE_T  val;
michael@0:   const MAU_T          *mem = (const MAU_T *)vmem;
michael@0: 
michael@0:   val = mem[2] << 16;
michael@0:   val |= mem[1] << 8;
michael@0:   val |= mem[0];
michael@0:   return val;
michael@0: }
michael@0: 
michael@0: #undef  mem_get_le32
michael@0: #define mem_get_le32 mem_ops_wrap_symbol(mem_get_le32)
michael@0: static unsigned MEM_VALUE_T mem_get_le32(const void *vmem) {
michael@0:   unsigned MEM_VALUE_T  val;
michael@0:   const MAU_T          *mem = (const MAU_T *)vmem;
michael@0: 
michael@0:   val = mem[3] << 24;
michael@0:   val |= mem[2] << 16;
michael@0:   val |= mem[1] << 8;
michael@0:   val |= mem[0];
michael@0:   return val;
michael@0: }
michael@0: 
michael@0: #define mem_get_s_generic(end,sz) \
michael@0:   static signed MEM_VALUE_T mem_get_s##end##sz(const void *vmem) {\
michael@0:     const MAU_T *mem = (const MAU_T*)vmem;\
michael@0:     signed MEM_VALUE_T val = mem_get_##end##sz(mem);\
michael@0:     return (val << (MEM_VALUE_T_SZ_BITS - sz)) >> (MEM_VALUE_T_SZ_BITS - sz);\
michael@0:   }
michael@0: 
michael@0: #undef  mem_get_sbe16
michael@0: #define mem_get_sbe16 mem_ops_wrap_symbol(mem_get_sbe16)
michael@0: mem_get_s_generic(be, 16)
michael@0: 
michael@0: #undef  mem_get_sbe24
michael@0: #define mem_get_sbe24 mem_ops_wrap_symbol(mem_get_sbe24)
michael@0: mem_get_s_generic(be, 24)
michael@0: 
michael@0: #undef  mem_get_sbe32
michael@0: #define mem_get_sbe32 mem_ops_wrap_symbol(mem_get_sbe32)
michael@0: mem_get_s_generic(be, 32)
michael@0: 
michael@0: #undef  mem_get_sle16
michael@0: #define mem_get_sle16 mem_ops_wrap_symbol(mem_get_sle16)
michael@0: mem_get_s_generic(le, 16)
michael@0: 
michael@0: #undef  mem_get_sle24
michael@0: #define mem_get_sle24 mem_ops_wrap_symbol(mem_get_sle24)
michael@0: mem_get_s_generic(le, 24)
michael@0: 
michael@0: #undef  mem_get_sle32
michael@0: #define mem_get_sle32 mem_ops_wrap_symbol(mem_get_sle32)
michael@0: mem_get_s_generic(le, 32)
michael@0: 
michael@0: #undef  mem_put_be16
michael@0: #define mem_put_be16 mem_ops_wrap_symbol(mem_put_be16)
michael@0: static void mem_put_be16(void *vmem, MEM_VALUE_T val) {
michael@0:   MAU_T *mem = (MAU_T *)vmem;
michael@0: 
michael@0:   mem[0] = (val >> 8) & 0xff;
michael@0:   mem[1] = (val >> 0) & 0xff;
michael@0: }
michael@0: 
michael@0: #undef  mem_put_be24
michael@0: #define mem_put_be24 mem_ops_wrap_symbol(mem_put_be24)
michael@0: static void mem_put_be24(void *vmem, MEM_VALUE_T val) {
michael@0:   MAU_T *mem = (MAU_T *)vmem;
michael@0: 
michael@0:   mem[0] = (val >> 16) & 0xff;
michael@0:   mem[1] = (val >>  8) & 0xff;
michael@0:   mem[2] = (val >>  0) & 0xff;
michael@0: }
michael@0: 
michael@0: #undef  mem_put_be32
michael@0: #define mem_put_be32 mem_ops_wrap_symbol(mem_put_be32)
michael@0: static void mem_put_be32(void *vmem, MEM_VALUE_T val) {
michael@0:   MAU_T *mem = (MAU_T *)vmem;
michael@0: 
michael@0:   mem[0] = (val >> 24) & 0xff;
michael@0:   mem[1] = (val >> 16) & 0xff;
michael@0:   mem[2] = (val >>  8) & 0xff;
michael@0:   mem[3] = (val >>  0) & 0xff;
michael@0: }
michael@0: 
michael@0: #undef  mem_put_le16
michael@0: #define mem_put_le16 mem_ops_wrap_symbol(mem_put_le16)
michael@0: static void mem_put_le16(void *vmem, MEM_VALUE_T val) {
michael@0:   MAU_T *mem = (MAU_T *)vmem;
michael@0: 
michael@0:   mem[0] = (val >>  0) & 0xff;
michael@0:   mem[1] = (val >>  8) & 0xff;
michael@0: }
michael@0: 
michael@0: #undef  mem_put_le24
michael@0: #define mem_put_le24 mem_ops_wrap_symbol(mem_put_le24)
michael@0: static void mem_put_le24(void *vmem, MEM_VALUE_T val) {
michael@0:   MAU_T *mem = (MAU_T *)vmem;
michael@0: 
michael@0:   mem[0] = (val >>  0) & 0xff;
michael@0:   mem[1] = (val >>  8) & 0xff;
michael@0:   mem[2] = (val >> 16) & 0xff;
michael@0: }
michael@0: 
michael@0: #undef  mem_put_le32
michael@0: #define mem_put_le32 mem_ops_wrap_symbol(mem_put_le32)
michael@0: static void mem_put_le32(void *vmem, MEM_VALUE_T val) {
michael@0:   MAU_T *mem = (MAU_T *)vmem;
michael@0: 
michael@0:   mem[0] = (val >>  0) & 0xff;
michael@0:   mem[1] = (val >>  8) & 0xff;
michael@0:   mem[2] = (val >> 16) & 0xff;
michael@0:   mem[3] = (val >> 24) & 0xff;
michael@0: }