src/add-ons/media/media-add-ons/mixer/ByteSwap.cpp

   1 /*
   2  * Copyright 2003-2007 Marcus Overhagen
   3  * Copyright 2007 Haiku Inc. All rights reserved.
   4  * Distributed under the terms of the MIT License.
   5  */
   6
   7
   8 #include "ByteSwap.h"
   9
  10 #include <ByteOrder.h>
  11 #include <MediaDefs.h>
  12
  13 #include "MixerDebug.h"
  14
  15
  16 static void swap_float(void *buffer, size_t bytecount);
  17 static void swap_int32(void *buffer, size_t bytecount);
  18 static void swap_int16(void *buffer, size_t bytecount);
  19 static void do_nothing(void *buffer, size_t bytecount);
  20
  21
  22 ByteSwap::ByteSwap(uint32 format)
  23 {
  24         switch (format) {
  25                 case media_raw_audio_format::B_AUDIO_FLOAT:
  26                         fFunc = &swap_float;
  27                         break;
  28                 case media_raw_audio_format::B_AUDIO_INT:
  29                         fFunc = &swap_int32;
  30                         break;
  31                 case media_raw_audio_format::B_AUDIO_SHORT:
  32                         fFunc = &swap_int16;
  33                         break;
  34                 default:
  35                         fFunc = &do_nothing;
  36                         break;
  37         }
  38 }
  39
  40
  41 ByteSwap::~ByteSwap()
  42 {
  43 }
  44
  45
  46 void
  47 do_nothing(void *buffer, size_t bytecount)
  48 {
  49 }
  50
  51
  52 #if __INTEL__
  53 // #pragma mark - optimized for IA32 platform
  54
  55
  56 void
  57 swap_float(void *buffer, size_t bytecount)
  58 {
  59         // XXX Should be optimized
  60         swap_data(B_FLOAT_TYPE, buffer, bytecount, B_SWAP_ALWAYS);
  61 }
  62
  63
  64 void
  65 swap_int32(void *buffer, size_t bytecount)
  66 {
  67         // XXX Should be optimized
  68         swap_data(B_INT32_TYPE, buffer, bytecount, B_SWAP_ALWAYS);
  69 }
  70
  71
  72 void
  73 swap_int16(void *buffer, size_t bytecount)
  74 {
  75         // GCC FAQ: To write an asm which modifies an input operand but does
  76         //          not output anything usable, specify that operand as an
  77         //          output operand outputting to an unused dummy variable.
  78         uint32 dummy1;
  79         uint32 dummy2;
  80          // GCC is way too smart and will remove the complete asm statement
  81          // if we do not specify it as __volatile__. Don't remove that!
  82         __asm__ __volatile__ (
  83         "pushl  %%ebx   \n\t"
  84         "movl   %%eax, %%ebx    \n\t"
  85         "movl   %%edx, %%eax    \n\t"
  86         "andl   $0xFFFFFFE0,%%eax       \n\t"
  87         "pushl  %%eax   \n\t"
  88         ".L_swap_loop: \n\t"
  89                 "rolw   $8,-32(%%ebx,%%eax)     \n\t"
  90                 "rolw   $8,-30(%%ebx,%%eax)     \n\t"
  91                 "rolw   $8,-28(%%ebx,%%eax)     \n\t"
  92                 "rolw   $8,-26(%%ebx,%%eax)     \n\t"
  93                 "rolw   $8,-24(%%ebx,%%eax)     \n\t"
  94                 "rolw   $8,-22(%%ebx,%%eax)     \n\t"
  95                 "rolw   $8,-20(%%ebx,%%eax)     \n\t"
  96                 "rolw   $8,-18(%%ebx,%%eax)     \n\t"
  97                 "rolw   $8,-16(%%ebx,%%eax)     \n\t"
  98                 "rolw   $8,-14(%%ebx,%%eax)     \n\t"
  99                 "rolw   $8,-12(%%ebx,%%eax)     \n\t"
 100                 "rolw   $8,-10(%%ebx,%%eax)     \n\t"
 101                 "rolw   $8,-8(%%ebx,%%eax)      \n\t"
 102                 "rolw   $8,-6(%%ebx,%%eax)      \n\t"
 103                 "rolw   $8,-4(%%ebx,%%eax)      \n\t"
 104                 "rolw   $8,-2(%%ebx,%%eax)      \n\t"
 105                 "subl   $32,%%eax       \n\t"
 106                 "jnz    .L_swap_loop    \n\t"
 107         "popl   %%eax   \n\t"
 108         "addl   %%eax,%%ebx     \n\t"
 109         "andl   $0x1F,%%edx     \n\t"
 110         "jz             .L_swap_end     \n\t"
 111         "addl   %%ebx, %%edx    \n\t"
 112         ".L_swap_loop_2: \n\t"
 113                 "rolw   $8,(%%ebx)      \n\t"
 114                 "addl   $2,%%ebx        \n\t"
 115                 "cmpl   %%edx,%%ebx     \n\t"
 116                 "jne    .L_swap_loop_2 \n\t"
 117         ".L_swap_end:   \n\t"
 118         "popl   %%ebx \n\t"
 119         : "=a" (dummy1), "=d" (dummy2)
 120         : "d" (bytecount), "a" (buffer)
 121         : "cc", "memory");
 122 }
 123
 124
 125 #else   // !__INTEL__
 126 // #pragma mark - generic versions
 127
 128
 129 void
 130 swap_float(void *buffer, size_t bytecount)
 131 {
 132         swap_data(B_FLOAT_TYPE, buffer, bytecount, B_SWAP_ALWAYS);
 133 }
 134
 135
 136 void
 137 swap_int32(void *buffer, size_t bytecount)
 138 {
 139         swap_data(B_INT32_TYPE, buffer, bytecount, B_SWAP_ALWAYS);
 140 }
 141
 142
 143 void
 144 swap_int16(void *buffer, size_t bytecount)
 145 {
 146         swap_data(B_INT16_TYPE, buffer, bytecount, B_SWAP_ALWAYS);
 147 }
 148
 149
 150 #endif