dsp2emu.c

/*******************************************************************************
  Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
 
  (c) Copyright 1996 - 2002 Gary Henderson (gary.henderson@ntlworld.com) and
                            Jerremy Koot (jkoot@snes9x.com)

  (c) Copyright 2001 - 2004 John Weidman (jweidman@slip.net)

  (c) Copyright 2002 - 2004 Brad Jorsch (anomie@users.sourceforge.net),
                            funkyass (funkyass@spam.shaw.ca),
                            Joel Yliluoma (http://iki.fi/bisqwit/)
                            Kris Bleakley (codeviolation@hotmail.com),
                            Matthew Kendora,
                            Nach (n-a-c-h@users.sourceforge.net),
                            Peter Bortas (peter@bortas.org) and
                            zones (kasumitokoduck@yahoo.com)

  C4 x86 assembler and some C emulation code
  (c) Copyright 2000 - 2003 zsKnight (zsknight@zsnes.com),
                            _Demo_ (_demo_@zsnes.com), and Nach

  C4 C++ code
  (c) Copyright 2003 Brad Jorsch

  DSP-1 emulator code
  (c) Copyright 1998 - 2004 Ivar (ivar@snes9x.com), _Demo_, Gary Henderson,
                            John Weidman, neviksti (neviksti@hotmail.com),
                            Kris Bleakley, Andreas Naive

  DSP-2 emulator code
  (c) Copyright 2003 Kris Bleakley, John Weidman, neviksti, Matthew Kendora, and
                     Lord Nightmare (lord_nightmare@users.sourceforge.net

  OBC1 emulator code
  (c) Copyright 2001 - 2004 zsKnight, pagefault (pagefault@zsnes.com) and
                            Kris Bleakley
  Ported from x86 assembler to C by sanmaiwashi

  SPC7110 and RTC C++ emulator code
  (c) Copyright 2002 Matthew Kendora with research by
                     zsKnight, John Weidman, and Dark Force

  S-DD1 C emulator code
  (c) Copyright 2003 Brad Jorsch with research by
                     Andreas Naive and John Weidman
 
  S-RTC C emulator code
  (c) Copyright 2001 John Weidman
  
  ST010 C++ emulator code
  (c) Copyright 2003 Feather, Kris Bleakley, John Weidman and Matthew Kendora

  Super FX x86 assembler emulator code 
  (c) Copyright 1998 - 2003 zsKnight, _Demo_, and pagefault 

  Super FX C emulator code 
  (c) Copyright 1997 - 1999 Ivar, Gary Henderson and John Weidman


  SH assembler code partly based on x86 assembler code
  (c) Copyright 2002 - 2004 Marcus Comstedt (marcus@mc.pp.se) 

 
  Specific ports contains the works of other authors. See headers in
  individual files.
 
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  source form, for non-commercial purposes, is hereby granted without fee,
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  warranty. In no event shall the authors be held liable for any damages
  arising from the use of this software.
 
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  seek permission of the copyright holders first. Commercial use includes
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  The copyright holders request that bug fixes and improvements to the code
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  in future versions.
 
  Super NES and Super Nintendo Entertainment System are trademarks of
  Nintendo Co., Limited and its subsidiary companies.
*******************************************************************************/

#include "port.h"

uint16 DSP2Op09Word1=0;
uint16 DSP2Op09Word2=0;
bool DSP2Op05HasLen=false;
int DSP2Op05Len=0;
bool DSP2Op06HasLen=false;
int DSP2Op06Len=0;
uint8 DSP2Op05Transparent=0;

void DSP2_Op05 ()
{
        uint8 color;
        // Overlay bitmap with transparency.
        // Input:
        //
        //   Bitmap 1:  i[0] <=> i[size-1]
        //   Bitmap 2:  i[size] <=> i[2*size-1]
        //
        // Output:
        //
        //   Bitmap 3:  o[0] <=> o[size-1]
        //
        // Processing:
        //
        //   Process all 4-bit pixels (nibbles) in the bitmap
        //
        //   if ( BM2_pixel == transparent_color )
        //      pixelout = BM1_pixel
        //   else
        //      pixelout = BM2_pixel

        // The max size bitmap is limited to 255 because the size parameter is a byte
        // I think size=0 is an error.  The behavior of the chip on size=0 is to
        // return the last value written to DR if you read DR on Op05 with
        // size = 0.  I don't think it's worth implementing this quirk unless it's
        // proven necessary.

        int n;
        unsigned char c1;
        unsigned char c2;
        unsigned char *p1 = DSP1.parameters;
        unsigned char *p2 = &DSP1.parameters[DSP2Op05Len];
        unsigned char *p3 = DSP1.output;

        color = DSP2Op05Transparent&0x0f;

        for( n = 0; n < DSP2Op05Len; n++ )
        {
                c1 = *p1++;
                c2 = *p2++;
                *p3++ = ( ((c2 >> 4) == color ) ? c1 & 0xf0: c2 & 0xf0 ) |
                        ( ((c2 & 0x0f)==color) ? c1 & 0x0f: c2 & 0x0f );
        }
}

void DSP2_Op01 ()
{
        // Op01 size is always 32 bytes input and output.
        // The hardware does strange things if you vary the size.
        
        int j;
        unsigned char c0, c1, c2, c3;
        unsigned char *p1 = DSP1.parameters;
        unsigned char *p2a = DSP1.output;
        unsigned char *p2b = &DSP1.output[16];	// halfway

        // Process 8 blocks of 4 bytes each

        for ( j = 0; j < 8; j++ )
        {
                c0 = *p1++;
                c1 = *p1++;
                c2 = *p1++;
                c3 = *p1++;

                *p2a++ = (c0 & 0x10) << 3 |
                             (c0 & 0x01) << 6 |
                             (c1 & 0x10) << 1 |
                             (c1 & 0x01) << 4 |
                             (c2 & 0x10) >> 1 |
                             (c2 & 0x01) << 2 |
                             (c3 & 0x10) >> 3 |
                             (c3 & 0x01);

                *p2a++ = (c0 & 0x20) << 2 |
                             (c0 & 0x02) << 5 |
                             (c1 & 0x20)      |
                             (c1 & 0x02) << 3 |
                             (c2 & 0x20) >> 2 |
                             (c2 & 0x02) << 1 |
                             (c3 & 0x20) >> 4 |
                             (c3 & 0x02) >> 1;

                *p2b++ = (c0 & 0x40) << 1 |
                             (c0 & 0x04) << 4 |
                             (c1 & 0x40) >> 1 |
                             (c1 & 0x04) << 2 |
                             (c2 & 0x40) >> 3 |
                             (c2 & 0x04)      |
                             (c3 & 0x40) >> 5 |
                             (c3 & 0x04) >> 2;


                *p2b++ = (c0 & 0x80)      |
                             (c0 & 0x08) << 3 |
                             (c1 & 0x80) >> 2 |
                             (c1 & 0x08) << 1 |
                             (c2 & 0x80) >> 4 |
                             (c2 & 0x08) >> 1 |
                             (c3 & 0x80) >> 6 |
                             (c3 & 0x08) >> 3;
        }
        return;
}

void DSP2_Op06 ()
{
        // Input:
        //    size
        //    bitmap

        int	i, j;

        for ( i = 0, j = DSP2Op06Len - 1; i < DSP2Op06Len; i++, j-- )
        {
                DSP1.output[j] = (DSP1.parameters[i] << 4) | (DSP1.parameters[i] >> 4);
        }
}

bool DSP2Op0DHasLen=false;
int DSP2Op0DOutLen=0;
int DSP2Op0DInLen=0;

#ifndef DSP2_BIT_ACCURRATE_CODE

// Scale bitmap based on input length out output length

void DSP2_Op0D()
{
        // Overload's algorithm - use this unless doing hardware testing

        // One note:  the HW can do odd byte scaling but since we divide
        // by two to get the count of bytes this won't work well for
        // odd byte scaling (in any of the current algorithm implementations).
        // So far I haven't seen Dungeon Master use it.
        // If it does we can adjust the parameters and code to work with it

        int i;
        int pixel_offset;
        uint8 pixelarray[512];

        for(i=0; i<DSP2Op0DOutLen*2; i++)
        {
                pixel_offset = (i * DSP2Op0DInLen) / DSP2Op0DOutLen;
                if ( (pixel_offset&1) == 0 )
                        pixelarray[i] = DSP1.parameters[pixel_offset>>1] >> 4;
                else
                        pixelarray[i] = DSP1.parameters[pixel_offset>>1] & 0x0f; 
        }

        for ( i=0; i < DSP2Op0DOutLen; i++ )
                DSP1.output[i] = ( pixelarray[i<<1] << 4 ) | pixelarray[(i<<1)+1];
}

#else

void DSP2_Op0D()
{
        // Bit accurate hardware algorithm - uses fixed point math
        // This should match the DSP2 Op0D output exactly
        // I wouldn't recommend using this unless you're doing hardware debug.
        // In some situations it has small visual artifacts that
        // are not readily apparent on a TV screen but show up clearly
        // on a monitor.  Use Overload's scaling instead.
        // This is for hardware verification testing.
        //
        // One note:  the HW can do odd byte scaling but since we divide
        // by two to get the count of bytes this won't work well for
        // odd byte scaling (in any of the current algorithm implementations).
        // So far I haven't seen Dungeon Master use it.
        // If it does we can adjust the parameters and code to work with it


        uint32 multiplier;	// Any size int >= 32-bits
        uint32 pixloc;		// match size of multiplier
        int	i, j;
        uint8 pixelarray[512];

        if (DSP2Op0DInLen <= DSP2Op0DOutLen)
                multiplier = 0x10000;	// In our self defined fixed point 0x10000 == 1
        else
                multiplier = (DSP2Op0DInLen << 17) / ((DSP2Op0DOutLen<<1) + 1);

        pixloc = 0;
        for ( i=0; i < DSP2Op0DOutLen * 2; i++ )
        {
                j = pixloc >> 16;

                if ( j & 1 )
                        pixelarray[i] = DSP1.parameters[j>>1] & 0x0f;
                else
                        pixelarray[i] = (DSP1.parameters[j>>1] & 0xf0) >> 4;

                pixloc += multiplier;
        }

        for ( i=0; i < DSP2Op0DOutLen; i++ )
                DSP1.output[i] = ( pixelarray[i<<1] << 4 ) | pixelarray[(i<<1)+1];
}

#endif

#if 0	// Probably no reason to use this code - it's not quite bit accurate and it doesn't look as good as Overload's algorithm

void DSP2_Op0D()
{
        // Float implementation of Neviksti's algorithm
        // This is the right algorithm to match the DSP2 bits but the precision
        // of the PC float does not match the precision of the fixed point math
        // on the DSP2 causing occasional one off data mismatches (which should
        // be no problem because its just a one pixel difference in a scaled image
        // to be displayed).

        float multiplier;
        float pixloc;
        int	i, j;
        uint8 pixelarray[512];

        if (DSP2Op0DInLen <= DSP2Op0DOutLen)
                multiplier = (float) 1.0;
        else
                multiplier = (float) ((DSP2Op0DInLen * 2.0) / (DSP2Op0DOutLen * 2.0 + 1.0));

        pixloc = 0.0;
        for ( i=0; i < DSP2Op0DOutLen * 2; i++ )
        {
                // j = (int)(i * multiplier);
                j = (int) pixloc;

                if ( j & 1 )
                        pixelarray[i] = DSP1.parameters[j>>1] & 0x0f;
                else
                        pixelarray[i] = (DSP1.parameters[j>>1] & 0xf0) >> 4;

                pixloc += multiplier;	// use an add in the loop instead of multiply to increase loop speed
        }

        for ( i=0; i < DSP2Op0DOutLen; i++ )
                DSP1.output[i] = ( pixelarray[i<<1] << 4 ) | pixelarray[(i<<1)+1];
}

#endif