obc1.cpp

/*******************************************************************************
  Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
 
  (c) Copyright 1996 - 2003 Gary Henderson (gary.henderson@ntlworld.com) and
                            Jerremy Koot (jkoot@snes9x.com)

  (c) Copyright 2002 - 2003 Matthew Kendora and
                            Brad Jorsch (anomie@users.sourceforge.net)
 

                      
  C4 x86 assembler and some C emulation code
  (c) Copyright 2000 - 2003 zsKnight (zsknight@zsnes.com),
                            _Demo_ (_demo_@zsnes.com), and
                            Nach (n-a-c-h@users.sourceforge.net)
                                          
  C4 C++ code
  (c) Copyright 2003 Brad Jorsch

  DSP-1 emulator code
  (c) Copyright 1998 - 2003 Ivar (ivar@snes9x.com), _Demo_, Gary Henderson,
                            John Weidman (jweidman@slip.net),
                            neviksti (neviksti@hotmail.com), and
                            Kris Bleakley (stinkfish@bigpond.com)
 
  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 - 2003 zsKnight, pagefault (pagefault@zsnes.com)
  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-RTC C emulator code
  (c) Copyright 2001 John Weidman
  
  Super FX x86 assembler emulator code 
  (c) Copyright 1998 - 2003 zsKnight, _Demo_, and pagefault 

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



 
  Specific ports contains the works of other authors. See headers in
  individual files.
 
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*******************************************************************************/

#include <string.h>
#include "memmap.h"
#include "obc1.h"

//#define OBC1_DEBUG

#define OBC1_REG_FLIP  0x0000
#define OBC1_OAM_ADDR  0x0008

static uint8 *obc1ram = NULL;

#ifdef OBC1_DEBUG
const static char obc1_log_name[] = "obc1.log";
static FILE *obc1_fs = NULL;
#endif

// Banks 00->3f and 80->bf
// 6000h-7FFFh OBC1 RAM register.

/* ZSNES comment.
; Affected values: 0,1,2,3,4,6,7,9,A,B
; 0,1 - Another X value (unused?)
; 2   - OAM value
; 3/4 - X value (bits 0-8)
; 5   - N/A (not written to)
; 6   - OAM #
; 7   - Always 0?
; 9   - Y value (bits 0-7)
; A   - OAM value
; B   - OAM Status
; X,Y,OAM,Attr / xhighbit / OAM highbit / Sprite size
;bit 0 = OAM b8, bit 1-3 = palette number bit 4,5 = playfield priority
;bit 6   = horizontal flip bit 7   = horizonal flip
; Extra: bit 0 = X bit 8, bit 1 = Larger sprite size


; SNES PPU 110h Word OAM Ram format.
; 000h-0FFh
; 4 bytes
; 0byte X
; 1byte Y
; 
; 3-4 bytes
; 0-8 bits pattern number
; 9-11 bits palette number
; 12-13 bits priority bits
; 14 bit H-Flip
; 15 bit V-Flip
; 
; 100h-10Fh
; bit0 X pos MSB
; bit1 sprite size (x4)
; 2bit * 128 == 10h word.
*/
extern "C"
{
uint8 GetOBC1 (uint16 Address)
{
#ifdef OBC1_DEBUG
	fprintf(obc1_fs, "0x%04X r 0x%02X\n", Address, obc1ram[Address & 0x1FFF]);
#endif
	return obc1ram[Address & 0x1FFF];
}

void SetOBC1 (uint8 Byte, uint16 Address)
{
	switch(Address) {
		case 0x7FF0:
		{
			obc1ram[0x1FF0] = Byte;
			obc1ram[READ_WORD(&Memory.FillRAM[OBC1_OAM_ADDR]) + 0x00] = Byte;
			
			obc1ram[((uint16)obc1ram[0x1FF6] << 4) + Memory.FillRAM[OBC1_REG_FLIP + 0] + 0] = Byte;
			Memory.FillRAM[OBC1_REG_FLIP + 0] ^= 0x08;
			break;
		}
		
		case 0x7FF1:
		{
			obc1ram[0x1FF1] = Byte;
			obc1ram[READ_WORD(&Memory.FillRAM[OBC1_OAM_ADDR]) + 0x01] = Byte;
			
			obc1ram[((uint16)obc1ram[0x1FF6] << 4) + Memory.FillRAM[OBC1_REG_FLIP + 1] + 1] = Byte;
			Memory.FillRAM[OBC1_REG_FLIP + 1] ^= 0x08;
			break;
		}
		
		case 0x7FF2:
		{
			obc1ram[0x1FF2] = Byte;
			obc1ram[READ_WORD(&Memory.FillRAM[OBC1_OAM_ADDR]) + 0x02] = Byte;
			
			obc1ram[((uint16)obc1ram[0x1FF6] << 4) + Memory.FillRAM[OBC1_REG_FLIP + 2] + 2] = Byte;
			Memory.FillRAM[OBC1_REG_FLIP + 2] ^= 0x08;
			break;
		}
		
		case 0x7FF3:
		{
			obc1ram[0x1FF3] = Byte;
			if(!Memory.FillRAM[OBC1_REG_FLIP + 3]) {
				obc1ram[READ_WORD(&Memory.FillRAM[OBC1_OAM_ADDR]) + 0x00] = Byte;
			}
			else {
				obc1ram[READ_WORD(&Memory.FillRAM[OBC1_OAM_ADDR]) + 0x03] = Byte;
			}
			
			obc1ram[((uint16)obc1ram[0x1FF6] << 4) + Memory.FillRAM[OBC1_REG_FLIP + 3] + 3] = Byte;
			Memory.FillRAM[OBC1_REG_FLIP + 3] ^= 0x08;
			break;
		}
		
		case 0x7FF4:
		{
			obc1ram[0x1FF4] = Byte;
			uint16 oami = 0x1800 + 0x200 + ((uint16)obc1ram[0x1FF6] >> 2);
			uint8 oams = ((obc1ram[0x1FF6] & 3) << 1);
			obc1ram[oami] = (obc1ram[oami] & ~(3 << oams)) | ((Byte & 3) << oams);
			
			obc1ram[((uint16)obc1ram[0x1FF6] << 4) + Memory.FillRAM[OBC1_REG_FLIP + 4] + 4] = Byte;
			Memory.FillRAM[OBC1_REG_FLIP + 4] ^= 0x08;
			break;
		}
		
		case 0x7FF5:
		{
			obc1ram[0x1FF5] = Byte;
			
			obc1ram[((uint16)obc1ram[0x1FF6] << 4) + Memory.FillRAM[OBC1_REG_FLIP + 5] + 5] = Byte;
			Memory.FillRAM[OBC1_REG_FLIP + 5] ^= 0x08;
			break;
		}
		
		case 0x7FF6:
		{
			Byte &= 0x7F;
			obc1ram[0x1FF6] = Byte;
			WRITE_WORD(&Memory.FillRAM[OBC1_OAM_ADDR], 0x1800 + (Byte << 2));
			*((uint32 *)&Memory.FillRAM[OBC1_REG_FLIP]) &= 0xF7F7F7F7;
			*((uint32 *)&Memory.FillRAM[OBC1_REG_FLIP + 4]) &= 0xF7F7F7F7;
			
			uint16 obci = (uint16)obc1ram[0x1FF6] << 4;
			uint16 oami = 0x1800 + (obci >> 2);
			obc1ram[oami + 0x00] = obc1ram[obci + 0x03];
			obc1ram[oami + 0x01] = obc1ram[obci + 0x09];
			obc1ram[oami + 0x02] = obc1ram[obci + 0x0A];
			obc1ram[oami + 0x03] = obc1ram[obci + 0x0B];
			uint16 oamii = 0x1800 + 0x200 + (oami >> 4);
			uint8 oams = ((obc1ram[0x1FF6] & 3) << 1);
			obc1ram[oamii] = (obc1ram[oamii] & ~(3 << oams)) | ((obc1ram[obci + 0x04] & 3) << oams);
			
			obc1ram[((uint16)obc1ram[0x1FF6] << 4) + 6] = Byte;
			break;
		}
		
		case 0x7FF7:
		{
			obc1ram[0x1FF7] = Byte;
			
			obc1ram[((uint16)obc1ram[0x1FF6] << 4) + Memory.FillRAM[OBC1_REG_FLIP + 7] + 7] = Byte;
			Memory.FillRAM[OBC1_REG_FLIP + 7] ^= 0x08;
			break;
		}
		
		default:
			obc1ram[Address & 0x1FFF] = Byte;
			break;
	}
#ifdef OBC1_DEBUG
	fprintf(obc1_fs, "0x%04X w 0x%02X\n", Address, Byte);
#endif
	return;
}

uint8 *GetBasePointerOBC1(uint32 Address)
{
	return Memory.FillRAM;
}

uint8 *GetMemPointerOBC1(uint32 Address)
{
	return (Memory.FillRAM + (Address & 0xFFFF));
}

void ResetOBC1()//bool8 full)
{
	obc1ram = &Memory.FillRAM[0x6000];
	memset(obc1ram, 0x00, 0x2000);
	memset(&Memory.FillRAM[OBC1_REG_FLIP], 0x00, 8);
	WRITE_WORD(&Memory.FillRAM[OBC1_OAM_ADDR], 0x1800);
#ifdef OBC1_DEBUG
	if(!obc1_fs)
		obc1_fs = fopen(obc1_log_name, "w");
#endif
	return;
}

}