/*
 * Copyright 2003-2007 Marcus Overhagen
 * Copyright 2007 Haiku Inc. All rights reserved.
 * Distributed under the terms of the MIT License.
 */


#include "ByteSwap.h"

#include <ByteOrder.h>
#include <MediaDefs.h>

#include "MixerDebug.h"


static void swap_float(void *buffer, size_t bytecount);
static void swap_int32(void *buffer, size_t bytecount);
static void swap_int16(void *buffer, size_t bytecount);
static void do_nothing(void *buffer, size_t bytecount);


ByteSwap::ByteSwap(uint32 format)
{
        switch (format) {
                case media_raw_audio_format::B_AUDIO_FLOAT:
                        fFunc = &swap_float;
                        break;
                case media_raw_audio_format::B_AUDIO_INT:
                        fFunc = &swap_int32;
                        break;
                case media_raw_audio_format::B_AUDIO_SHORT:
                        fFunc = &swap_int16;
                        break;
                default:
                        fFunc = &do_nothing;
                        break;
        }
}


ByteSwap::~ByteSwap()
{
}


void
do_nothing(void *buffer, size_t bytecount)
{
}


#if __i386__
// #pragma mark - optimized for IA32 platform


void
swap_float(void *buffer, size_t bytecount)
{
        // XXX Should be optimized
        swap_data(B_FLOAT_TYPE, buffer, bytecount, B_SWAP_ALWAYS);
}


void
swap_int32(void *buffer, size_t bytecount)
{
        // XXX Should be optimized
        swap_data(B_INT32_TYPE, buffer, bytecount, B_SWAP_ALWAYS);
}


void
swap_int16(void *buffer, size_t bytecount)
{
        // GCC FAQ: To write an asm which modifies an input operand but does
        //          not output anything usable, specify that operand as an
        //          output operand outputting to an unused dummy variable.
        uint32 dummy1;
        uint32 dummy2;
         // GCC is way too smart and will remove the complete asm statement
         // if we do not specify it as __volatile__. Don't remove that!
        __asm__ __volatile__ (
        "pushl  %%ebx   \n\t"
        "movl   %%eax, %%ebx    \n\t"
        "movl   %%edx, %%eax    \n\t"
        "andl   $0xFFFFFFE0,%%eax       \n\t"
        "pushl  %%eax   \n\t"
        ".L_swap_loop: \n\t"
                "rolw   $8,-32(%%ebx,%%eax)     \n\t"
                "rolw   $8,-30(%%ebx,%%eax)     \n\t"
                "rolw   $8,-28(%%ebx,%%eax)     \n\t"
                "rolw   $8,-26(%%ebx,%%eax)     \n\t"
                "rolw   $8,-24(%%ebx,%%eax)     \n\t"
                "rolw   $8,-22(%%ebx,%%eax)     \n\t"
                "rolw   $8,-20(%%ebx,%%eax)     \n\t"
                "rolw   $8,-18(%%ebx,%%eax)     \n\t"
                "rolw   $8,-16(%%ebx,%%eax)     \n\t"
                "rolw   $8,-14(%%ebx,%%eax)     \n\t"
                "rolw   $8,-12(%%ebx,%%eax)     \n\t"
                "rolw   $8,-10(%%ebx,%%eax)     \n\t"
                "rolw   $8,-8(%%ebx,%%eax)      \n\t"
                "rolw   $8,-6(%%ebx,%%eax)      \n\t"
                "rolw   $8,-4(%%ebx,%%eax)      \n\t"
                "rolw   $8,-2(%%ebx,%%eax)      \n\t"
                "subl   $32,%%eax       \n\t"
                "jnz    .L_swap_loop    \n\t"
        "popl   %%eax   \n\t"
        "addl   %%eax,%%ebx     \n\t"
        "andl   $0x1F,%%edx     \n\t"
        "jz             .L_swap_end     \n\t"
        "addl   %%ebx, %%edx    \n\t"
        ".L_swap_loop_2: \n\t"
                "rolw   $8,(%%ebx)      \n\t"
                "addl   $2,%%ebx        \n\t"
                "cmpl   %%edx,%%ebx     \n\t"
                "jne    .L_swap_loop_2 \n\t"
        ".L_swap_end:   \n\t"
        "popl   %%ebx \n\t"
        : "=a" (dummy1), "=d" (dummy2)
        : "d" (bytecount), "a" (buffer)
        : "cc", "memory");
}


#else   // !__i386__
// #pragma mark - generic versions


void
swap_float(void *buffer, size_t bytecount)
{
        swap_data(B_FLOAT_TYPE, buffer, bytecount, B_SWAP_ALWAYS);
}


void
swap_int32(void *buffer, size_t bytecount)
{
        swap_data(B_INT32_TYPE, buffer, bytecount, B_SWAP_ALWAYS);
}


void
swap_int16(void *buffer, size_t bytecount)
{
        swap_data(B_INT16_TYPE, buffer, bytecount, B_SWAP_ALWAYS);
}


#endif