/
InfoNES.c
1182 lines (979 loc) · 33.8 KB
/
InfoNES.c
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
*
* Rockbox port of InfoNES
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
/*-------------------------------------------------------------------*/
/* Include files */
/*-------------------------------------------------------------------*/
#include "InfoNES.h"
#include "InfoNES_System.h"
#include "InfoNES_Mapper.h"
#include "InfoNES_pAPU.h"
#include "K6502.h"
/*-------------------------------------------------------------------*/
/* NES resources */
/*-------------------------------------------------------------------*/
/* RAM */
BYTE RAM[ RAM_SIZE ];
/* SRAM */
BYTE SRAM[ SRAM_SIZE ];
/* ROM */
BYTE *ROM;
/* SRAM BANK ( 8Kb ) */
BYTE *SRAMBANK;
/* ROM BANK ( 8Kb * 4 ) */
BYTE *ROMBANK0;
BYTE *ROMBANK1;
BYTE *ROMBANK2;
BYTE *ROMBANK3;
/*-------------------------------------------------------------------*/
/* PPU resources */
/*-------------------------------------------------------------------*/
/* PPU RAM */
BYTE PPURAM[ PPURAM_SIZE ];
/* VROM */
BYTE *VROM;
/* PPU BANK ( 1Kb * 16 ) */
BYTE *PPUBANK[ 16 ];
/* Sprite RAM */
BYTE SPRRAM[ SPRRAM_SIZE ];
/* PPU Register */
BYTE PPU_R0;
BYTE PPU_R1;
BYTE PPU_R2;
BYTE PPU_R3;
BYTE PPU_R7;
/* Vertical scroll value */
BYTE PPU_Scr_V;
BYTE PPU_Scr_V_Next;
BYTE PPU_Scr_V_Byte;
BYTE PPU_Scr_V_Byte_Next;
BYTE PPU_Scr_V_Bit;
BYTE PPU_Scr_V_Bit_Next;
/* Horizontal scroll value */
BYTE PPU_Scr_H;
BYTE PPU_Scr_H_Next;
BYTE PPU_Scr_H_Byte;
BYTE PPU_Scr_H_Byte_Next;
BYTE PPU_Scr_H_Bit;
BYTE PPU_Scr_H_Bit_Next;
/* PPU Address */
WORD PPU_Addr;
/* PPU Address */
WORD PPU_Temp;
/* The increase value of the PPU Address */
WORD PPU_Increment;
/* Current Scanline */
WORD PPU_Scanline;
/* Scanline Table */
BYTE PPU_ScanTable[ 263 ];
/* Name Table Bank */
BYTE PPU_NameTableBank;
/* BG Base Address */
BYTE *PPU_BG_Base;
/* Sprite Base Address */
BYTE *PPU_SP_Base;
/* Sprite Height */
WORD PPU_SP_Height;
/* Sprite #0 Scanline Hit Position */
int SpriteJustHit;
/* VRAM Write Enable ( 0: Disable, 1: Enable ) */
BYTE byVramWriteEnable;
/* PPU Address and Scroll Latch Flag*/
BYTE PPU_Latch_Flag;
/* Up and Down Clipping Flag ( 0: non-clip, 1: clip ) */
BYTE PPU_UpDown_Clip;
/* Frame IRQ ( 0: Disabled, 1: Enabled )*/
BYTE FrameIRQ_Enable;
WORD FrameStep;
/*-------------------------------------------------------------------*/
/* Display and Others resouces */
/*-------------------------------------------------------------------*/
/* Frame Skip */
WORD FrameSkip;
WORD FrameCnt;
/* Display Buffer */
#if 0
WORD DoubleFrame[ 2 ][ NES_DISP_WIDTH * NES_DISP_HEIGHT ];
WORD *WorkFrame;
WORD WorkFrameIdx;
#else
WORD WorkFrame[ NES_DISP_WIDTH * NES_DISP_HEIGHT ];
#endif
/* Character Buffer */
BYTE ChrBuf[ 256 * 2 * 8 * 8 ];
/* Update flag for ChrBuf */
BYTE ChrBufUpdate;
/* Palette Table */
WORD PalTable[ 32 ];
/* Table for Mirroring */
BYTE PPU_MirrorTable[][ 4 ] =
{
{ NAME_TABLE0, NAME_TABLE0, NAME_TABLE1, NAME_TABLE1 },
{ NAME_TABLE0, NAME_TABLE1, NAME_TABLE0, NAME_TABLE1 },
{ NAME_TABLE1, NAME_TABLE1, NAME_TABLE1, NAME_TABLE1 },
{ NAME_TABLE0, NAME_TABLE0, NAME_TABLE0, NAME_TABLE0 },
{ NAME_TABLE0, NAME_TABLE1, NAME_TABLE2, NAME_TABLE3 },
{ NAME_TABLE0, NAME_TABLE0, NAME_TABLE0, NAME_TABLE1 }
};
/*-------------------------------------------------------------------*/
/* APU and Pad resources */
/*-------------------------------------------------------------------*/
/* APU Register */
BYTE APU_Reg[ 0x18 ];
/* APU Mute ( 0:OFF, 1:ON ) */
int APU_Mute = 0;
/* Pad data */
DWORD PAD1_Latch;
DWORD PAD2_Latch;
DWORD PAD_System;
DWORD PAD1_Bit;
DWORD PAD2_Bit;
/*-------------------------------------------------------------------*/
/* Mapper Function */
/*-------------------------------------------------------------------*/
/* Initialize Mapper */
void (*MapperInit)(void);
/* Write to Mapper */
void (*MapperWrite)( WORD wAddr, BYTE byData );
/* Write to SRAM */
void (*MapperSram)( WORD wAddr, BYTE byData );
/* Write to Apu */
void (*MapperApu)( WORD wAddr, BYTE byData );
/* Read from Apu */
BYTE (*MapperReadApu)( WORD wAddr );
/* Callback at VSync */
void (*MapperVSync)(void);
/* Callback at HSync */
void (*MapperHSync)(void);
/* Callback at PPU read/write */
void (*MapperPPU)( WORD wAddr );
/* Callback at Rendering Screen 1:BG, 0:Sprite */
void (*MapperRenderScreen)( BYTE byMode );
/*-------------------------------------------------------------------*/
/* ROM information */
/*-------------------------------------------------------------------*/
/* .nes File Header */
struct NesHeader_tag NesHeader;
/* Mapper Number */
BYTE MapperNo;
/* Mirroring 0:Horizontal 1:Vertical */
BYTE ROM_Mirroring;
/* It has SRAM */
BYTE ROM_SRAM;
/* It has Trainer */
BYTE ROM_Trainer;
/* Four screen VRAM */
BYTE ROM_FourScr;
/*===================================================================*/
/* */
/* InfoNES_Init() : Initialize InfoNES */
/* */
/*===================================================================*/
void InfoNES_Init()
{
/*
* Initialize InfoNES
*
* Remarks
* Initialize K6502 and Scanline Table.
*/
int nIdx;
/* Initialize 6502 */
K6502_Init();
/* Initialize Scanline Table */
for ( nIdx = 0; nIdx < 263; ++nIdx )
{
if ( nIdx < SCAN_ON_SCREEN_START )
PPU_ScanTable[ nIdx ] = SCAN_ON_SCREEN;
else
if ( nIdx < SCAN_BOTTOM_OFF_SCREEN_START )
PPU_ScanTable[ nIdx ] = SCAN_ON_SCREEN;
else
if ( nIdx < SCAN_UNKNOWN_START )
PPU_ScanTable[ nIdx ] = SCAN_ON_SCREEN;
else
if ( nIdx < SCAN_VBLANK_START )
PPU_ScanTable[ nIdx ] = SCAN_UNKNOWN;
else
PPU_ScanTable[ nIdx ] = SCAN_VBLANK;
}
}
/*===================================================================*/
/* */
/* InfoNES_Fin() : Completion treatment */
/* */
/*===================================================================*/
void InfoNES_Fin()
{
/*
* Completion treatment
*
* Remarks
* Release resources
*/
/* Finalize pAPU */
InfoNES_pAPUDone();
/* Release a memory for ROM */
InfoNES_ReleaseRom();
}
/*===================================================================*/
/* */
/* InfoNES_Load() : Load a cassette */
/* */
/*===================================================================*/
int InfoNES_Load( const char *pszFileName )
{
/*
* Load a cassette
*
* Parameters
* const char *pszFileName (Read)
* File name of ROM image
*
* Return values
* 0 : It was finished normally.
* -1 : An error occurred.
*
* Remarks
* Read a ROM image in the memory.
* Reset InfoNES.
*/
/* Release a memory for ROM */
InfoNES_ReleaseRom();
/* Read a ROM image in the memory */
if ( InfoNES_ReadRom( pszFileName ) < 0 )
return -1;
/* Reset InfoNES */
if ( InfoNES_Reset() < 0 )
return -1;
/* Successful */
return 0;
}
/*===================================================================*/
/* */
/* InfoNES_Reset() : Reset InfoNES */
/* */
/*===================================================================*/
int InfoNES_Reset()
{
/*
* Reset InfoNES
*
* Return values
* 0 : Normally
* -1 : Non support mapper
*
* Remarks
* Initialize Resources, PPU and Mapper.
* Reset CPU.
*/
int nIdx;
/*-------------------------------------------------------------------*/
/* Get information on the cassette */
/*-------------------------------------------------------------------*/
/* Get Mapper Number */
MapperNo = NesHeader.byInfo1 >> 4;
/* MapperNo = 4; */
/* Check bit counts of Mapper No. */
for ( nIdx = 4; nIdx < 8 && NesHeader.byReserve[ nIdx ] == 0; ++nIdx )
;
if ( nIdx == 8 )
{
/* Mapper Number is 8bits */
MapperNo |= ( NesHeader.byInfo2 & 0xf0 );
}
/* Get information on the ROM */
ROM_Mirroring = NesHeader.byInfo1 & 1;
ROM_SRAM = NesHeader.byInfo1 & 2;
ROM_Trainer = NesHeader.byInfo1 & 4;
ROM_FourScr = NesHeader.byInfo1 & 8;
/*-------------------------------------------------------------------*/
/* Initialize resources */
/*-------------------------------------------------------------------*/
/* Clear RAM */
InfoNES_MemorySet( RAM, 0, sizeof RAM );
/* Reset frame skip and frame count */
FrameSkip = 0;
FrameCnt = 0;
#if 0
/* Reset work frame */
WorkFrame = DoubleFrame[ 0 ];
WorkFrameIdx = 0;
#endif
/* Reset update flag of ChrBuf */
ChrBufUpdate = 0xff;
/* Reset palette table */
InfoNES_MemorySet( PalTable, 0, sizeof PalTable );
/* Reset APU register */
InfoNES_MemorySet( APU_Reg, 0, sizeof APU_Reg );
/* Reset joypad */
PAD1_Latch = PAD2_Latch = PAD_System = 0;
PAD1_Bit = PAD2_Bit = 0;
/*-------------------------------------------------------------------*/
/* Initialize PPU */
/*-------------------------------------------------------------------*/
InfoNES_SetupPPU();
/*-------------------------------------------------------------------*/
/* Initialize pAPU */
/*-------------------------------------------------------------------*/
InfoNES_pAPUInit();
/*-------------------------------------------------------------------*/
/* Initialize Mapper */
/*-------------------------------------------------------------------*/
/* Get Mapper Table Index */
for ( nIdx = 0; MapperTable[ nIdx ].nMapperNo != -1; ++nIdx )
{
if ( MapperTable[ nIdx ].nMapperNo == MapperNo )
break;
}
if ( MapperTable[ nIdx ].nMapperNo == -1 )
{
/* Non support mapper */
InfoNES_MessageBox( "Mapper #%d is unsupported.\n", MapperNo );
return -1;
}
/* Set up a mapper initialization function */
MapperTable[ nIdx ].pMapperInit();
/*-------------------------------------------------------------------*/
/* Reset CPU */
/*-------------------------------------------------------------------*/
K6502_Reset();
/* Successful */
return 0;
}
/*===================================================================*/
/* */
/* InfoNES_SetupPPU() : Initialize PPU */
/* */
/*===================================================================*/
void InfoNES_SetupPPU()
{
/*
* Initialize PPU
*
*/
int nPage;
/* Clear PPU and Sprite Memory */
InfoNES_MemorySet( PPURAM, 0, sizeof PPURAM );
InfoNES_MemorySet( SPRRAM, 0, sizeof SPRRAM );
/* Reset PPU Register */
PPU_R0 = PPU_R1 = PPU_R2 = PPU_R3 = PPU_R7 = 0;
/* Reset latch flag */
PPU_Latch_Flag = 0;
/* Reset up and down clipping flag */
PPU_UpDown_Clip = 0;
FrameStep = 0;
FrameIRQ_Enable = 0;
/* Reset Scroll values */
PPU_Scr_V = PPU_Scr_V_Next = PPU_Scr_V_Byte = PPU_Scr_V_Byte_Next = PPU_Scr_V_Bit = PPU_Scr_V_Bit_Next = 0;
PPU_Scr_H = PPU_Scr_H_Next = PPU_Scr_H_Byte = PPU_Scr_H_Byte_Next = PPU_Scr_H_Bit = PPU_Scr_H_Bit_Next = 0;
/* Reset PPU address */
PPU_Addr = 0;
PPU_Temp = 0;
/* Reset scanline */
PPU_Scanline = 0;
/* Reset hit position of sprite #0 */
SpriteJustHit = 0;
/* Reset information on PPU_R0 */
PPU_Increment = 1;
PPU_NameTableBank = NAME_TABLE0;
PPU_BG_Base = ChrBuf;
PPU_SP_Base = ChrBuf + 256 * 64;
PPU_SP_Height = 8;
/* Reset PPU banks */
for ( nPage = 0; nPage < 16; ++nPage )
PPUBANK[ nPage ] = &PPURAM[ nPage * 0x400 ];
/* Mirroring of Name Table */
InfoNES_Mirroring( ROM_Mirroring );
/* Reset VRAM Write Enable */
byVramWriteEnable = ( NesHeader.byVRomSize == 0 ) ? 1 : 0;
}
/*===================================================================*/
/* */
/* InfoNES_Mirroring() : Set up a Mirroring of Name Table */
/* */
/*===================================================================*/
void InfoNES_Mirroring( int nType )
{
/*
* Set up a Mirroring of Name Table
*
* Parameters
* int nType (Read)
* Mirroring Type
* 0 : Horizontal
* 1 : Vertical
* 2 : One Screen 0x2400
* 3 : One Screen 0x2000
* 4 : Four Screen
* 5 : Special for Mapper #233
*/
PPUBANK[ NAME_TABLE0 ] = &PPURAM[ PPU_MirrorTable[ nType ][ 0 ] * 0x400 ];
PPUBANK[ NAME_TABLE1 ] = &PPURAM[ PPU_MirrorTable[ nType ][ 1 ] * 0x400 ];
PPUBANK[ NAME_TABLE2 ] = &PPURAM[ PPU_MirrorTable[ nType ][ 2 ] * 0x400 ];
PPUBANK[ NAME_TABLE3 ] = &PPURAM[ PPU_MirrorTable[ nType ][ 3 ] * 0x400 ];
}
/*===================================================================*/
/* */
/* InfoNES_Main() : The main loop of InfoNES */
/* */
/*===================================================================*/
void InfoNES_Main()
{
/*
* The main loop of InfoNES
*
*/
/* Initialize InfoNES */
InfoNES_Init();
/* Main loop */
while ( 1 )
{
/*-------------------------------------------------------------------*/
/* To the menu screen */
/*-------------------------------------------------------------------*/
if ( InfoNES_Menu() == -1 )
break; /* Quit */
/*-------------------------------------------------------------------*/
/* Start a NES emulation */
/*-------------------------------------------------------------------*/
InfoNES_Cycle();
}
/* Completion treatment */
InfoNES_Fin();
}
/*===================================================================*/
/* */
/* InfoNES_Cycle() : The loop of emulation */
/* */
/*===================================================================*/
void InfoNES_Cycle()
{
/*
* The loop of emulation
*
*/
#if 0
/* Set the PPU adress to the buffered value */
if ( ( PPU_R1 & R1_SHOW_SP ) || ( PPU_R1 & R1_SHOW_SCR ) )
PPU_Addr = PPU_Temp;
#endif
/* Emulation loop */
for (;;)
{
int nStep;
/* Set a flag if a scanning line is a hit in the sprite #0 */
if ( SpriteJustHit == PPU_Scanline &&
PPU_ScanTable[ PPU_Scanline ] == SCAN_ON_SCREEN )
{
/* # of Steps to execute before sprite #0 hit */
nStep = SPRRAM[ SPR_X ] * STEP_PER_SCANLINE / NES_DISP_WIDTH;
/* Execute instructions */
K6502_Step( nStep );
/* Set a sprite hit flag */
if ( ( PPU_R1 & R1_SHOW_SP ) && ( PPU_R1 & R1_SHOW_SCR ) )
PPU_R2 |= R2_HIT_SP;
/* NMI is required if there is necessity */
if ( ( PPU_R0 & R0_NMI_SP ) && ( PPU_R1 & R1_SHOW_SP ) )
NMI_REQ;
/* Execute instructions */
K6502_Step( STEP_PER_SCANLINE - nStep );
}
else
{
/* Execute instructions */
K6502_Step( STEP_PER_SCANLINE );
}
/* Frame IRQ in H-Sync */
FrameStep += STEP_PER_SCANLINE;
if ( FrameStep > STEP_PER_FRAME && FrameIRQ_Enable )
{
FrameStep %= STEP_PER_FRAME;
IRQ_REQ;
APU_Reg[ 0x4015 ] |= 0x40;
}
/* A mapper function in H-Sync */
MapperHSync();
/* A function in H-Sync */
if ( InfoNES_HSync() == -1 )
return; /* To the menu screen */
/* HSYNC Wait */
InfoNES_Wait();
}
}
/*===================================================================*/
/* */
/* InfoNES_HSync() : A function in H-Sync */
/* */
/*===================================================================*/
int InfoNES_HSync()
{
/*
* A function in H-Sync
*
* Return values
* 0 : Normally
* -1 : Exit an emulation
*/
/*-------------------------------------------------------------------*/
/* Render a scanline */
/*-------------------------------------------------------------------*/
if ( FrameCnt == 0 &&
PPU_ScanTable[ PPU_Scanline ] == SCAN_ON_SCREEN )
{
InfoNES_DrawLine();
}
/*-------------------------------------------------------------------*/
/* Set new scroll values */
/*-------------------------------------------------------------------*/
PPU_Scr_V = PPU_Scr_V_Next;
PPU_Scr_V_Byte = PPU_Scr_V_Byte_Next;
PPU_Scr_V_Bit = PPU_Scr_V_Bit_Next;
PPU_Scr_H = PPU_Scr_H_Next;
PPU_Scr_H_Byte = PPU_Scr_H_Byte_Next;
PPU_Scr_H_Bit = PPU_Scr_H_Bit_Next;
/*-------------------------------------------------------------------*/
/* Next Scanline */
/*-------------------------------------------------------------------*/
PPU_Scanline = ( PPU_Scanline == SCAN_VBLANK_END ) ? 0 : PPU_Scanline + 1;
/*-------------------------------------------------------------------*/
/* Operation in the specific scanning line */
/*-------------------------------------------------------------------*/
switch ( PPU_Scanline )
{
case SCAN_TOP_OFF_SCREEN:
/* Reset a PPU status */
PPU_R2 = 0;
/* Set up a character data */
if ( NesHeader.byVRomSize == 0 && FrameCnt == 0 )
InfoNES_SetupChr();
/* Get position of sprite #0 */
InfoNES_GetSprHitY();
break;
case SCAN_UNKNOWN_START:
if ( FrameCnt == 0 )
{
/* Transfer the contents of work frame on the screen */
InfoNES_LoadFrame();
#if 0
/* Switching of the double buffer */
WorkFrameIdx = 1 - WorkFrameIdx;
WorkFrame = DoubleFrame[ WorkFrameIdx ];
#endif
}
break;
case SCAN_VBLANK_START:
/* FrameCnt + 1 */
FrameCnt = ( FrameCnt >= FrameSkip ) ? 0 : FrameCnt + 1;
/* Set a V-Blank flag */
PPU_R2 = R2_IN_VBLANK;
/* Reset latch flag */
PPU_Latch_Flag = 0;
/* pAPU Sound function in V-Sync */
if ( !APU_Mute )
InfoNES_pAPUVsync();
/* A mapper function in V-Sync */
MapperVSync();
/* Get the condition of the joypad */
InfoNES_PadState( &PAD1_Latch, &PAD2_Latch, &PAD_System );
/* NMI on V-Blank */
if ( PPU_R0 & R0_NMI_VB )
NMI_REQ;
/* Exit an emulation if a QUIT button is pushed */
if ( PAD_PUSH( PAD_System, PAD_SYS_QUIT ) )
return -1; /* Exit an emulation */
break;
}
/* Successful */
return 0;
}
/*===================================================================*/
/* */
/* InfoNES_DrawLine() : Render a scanline */
/* */
/*===================================================================*/
void InfoNES_DrawLine()
{
/*
* Render a scanline
*
*/
int nX;
int nY;
int nY4;
int nYBit;
WORD *pPalTbl;
BYTE *pAttrBase;
WORD *pPoint;
int nNameTable;
BYTE *pbyNameTable;
BYTE *pbyChrData;
BYTE *pbyChrDataStart;
BYTE *pSPRRAM;
int nAttr;
int nSprCnt;
int nIdx;
int nSprData;
BYTE bySprCol;
BYTE pSprBuf[ NES_DISP_WIDTH + 7 ];
/*-------------------------------------------------------------------*/
/* Render Background */
/*-------------------------------------------------------------------*/
/* MMC5 VROM switch */
MapperRenderScreen( 1 );
/* Pointer to the render position */
pPoint = &WorkFrame[ PPU_Scanline * NES_DISP_WIDTH ];
/* Clear a scanline if screen is off */
if ( !( PPU_R1 & R1_SHOW_SCR ) )
{
InfoNES_MemorySet( pPoint, 0, NES_DISP_WIDTH << 1 );
}
else
{
nNameTable = PPU_NameTableBank;
nY = PPU_Scr_V_Byte + ( PPU_Scanline >> 3 );
nYBit = PPU_Scr_V_Bit + ( PPU_Scanline & 7 );
if ( nYBit > 7 )
{
++nY;
nYBit &= 7;
}
nYBit <<= 3;
if ( nY > 29 )
{
/* Next NameTable (An up-down direction) */
nNameTable ^= NAME_TABLE_V_MASK;
nY -= 30;
}
nX = PPU_Scr_H_Byte;
nY4 = ( ( nY & 2 ) << 1 );
/*-------------------------------------------------------------------*/
/* Rendering of the block of the left end */
/*-------------------------------------------------------------------*/
pbyNameTable = PPUBANK[ nNameTable ] + nY * 32 + nX;
pbyChrData = PPU_BG_Base + ( *pbyNameTable << 6 ) + nYBit;
pAttrBase = PPUBANK[ nNameTable ] + 0x3c0 + ( nY / 4 ) * 8;
pPalTbl = &PalTable[ ( ( ( pAttrBase[ nX >> 2 ] >> ( ( nX & 2 ) + nY4 ) ) & 3 ) << 2 ) ];
for ( nIdx = PPU_Scr_H_Bit; nIdx < 8; ++nIdx )
{
*( pPoint++ ) = pPalTbl[ pbyChrData[ nIdx ] ];
}
/* Callback at PPU read/write */
MapperPPU( PATTBL( pbyChrData ) );
++nX;
++pbyNameTable;
/*-------------------------------------------------------------------*/
/* Rendering of the left table */
/*-------------------------------------------------------------------*/
for ( ; nX < 32; ++nX )
{
pbyChrData = PPU_BG_Base + ( *pbyNameTable << 6 ) + nYBit;
pPalTbl = &PalTable[ ( ( ( pAttrBase[ nX >> 2 ] >> ( ( nX & 2 ) + nY4 ) ) & 3 ) << 2 ) ];
pbyChrDataStart = pbyChrData;
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
/* Callback at PPU read/write */
MapperPPU( PATTBL( pbyChrData ) );
++pbyNameTable;
}
/* Holizontal Mirror */
nNameTable ^= NAME_TABLE_H_MASK;
pbyNameTable = PPUBANK[ nNameTable ] + nY * 32;
pAttrBase = PPUBANK[ nNameTable ] + 0x3c0 + ( nY / 4 ) * 8;
/*-------------------------------------------------------------------*/
/* Rendering of the right table */
/*-------------------------------------------------------------------*/
for ( nX = 0; nX < PPU_Scr_H_Byte; ++nX )
{
pbyChrData = PPU_BG_Base + ( *pbyNameTable << 6 ) + nYBit;
pPalTbl = &PalTable[ ( ( ( pAttrBase[ nX >> 2 ] >> ( ( nX & 2 ) + nY4 ) ) & 3 ) << 2 ) ];
pbyChrDataStart = pbyChrData;
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
*pPoint++ = pPalTbl[ *pbyChrDataStart++ ];
/* Callback at PPU read/write */
MapperPPU( PATTBL( pbyChrData ) );
++pbyNameTable;
}
/*-------------------------------------------------------------------*/
/* Rendering of the block of the right end */
/*-------------------------------------------------------------------*/
pbyChrData = PPU_BG_Base + ( *pbyNameTable << 6 ) + nYBit;
pPalTbl = &PalTable[ ( ( ( pAttrBase[ nX >> 2 ] >> ( ( nX & 2 ) + nY4 ) ) & 3 ) << 2 ) ];
for ( nIdx = 0; nIdx < PPU_Scr_H_Bit; ++nIdx )
{
pPoint[ nIdx ] = pPalTbl[ pbyChrData[ nIdx ] ];
}
/* Callback at PPU read/write */
MapperPPU( PATTBL( pbyChrData ) );
/*-------------------------------------------------------------------*/
/* Backgroud Clipping */
/*-------------------------------------------------------------------*/
if ( !( PPU_R1 & R1_CLIP_BG ) )
{
WORD *pPointTop;
pPointTop = &WorkFrame[ PPU_Scanline * NES_DISP_WIDTH ];
InfoNES_MemorySet( pPointTop, 0, 8 << 1 );
}
/*-------------------------------------------------------------------*/
/* Clear a scanline if up and down clipping flag is set */
/*-------------------------------------------------------------------*/
if ( PPU_UpDown_Clip &&
( SCAN_ON_SCREEN_START > PPU_Scanline || PPU_Scanline > SCAN_BOTTOM_OFF_SCREEN_START ) )
{
WORD *pPointTop;
pPointTop = &WorkFrame[ PPU_Scanline * NES_DISP_WIDTH ];
InfoNES_MemorySet( pPointTop, 0, NES_DISP_WIDTH << 1 );
}
}
/*-------------------------------------------------------------------*/
/* Render a sprite */
/*-------------------------------------------------------------------*/
/* MMC5 VROM switch */
MapperRenderScreen( 0 );
if ( PPU_R1 & R1_SHOW_SP )
{
/* Reset Scanline Sprite Count */
PPU_R2 &= ~R2_MAX_SP;
/* Reset sprite buffer */
InfoNES_MemorySet( pSprBuf, 0, sizeof pSprBuf );
/* Render a sprite to the sprite buffer */
nSprCnt = 0;
for ( pSPRRAM = SPRRAM + ( 63 << 2 ); pSPRRAM >= SPRRAM; pSPRRAM -= 4 )
{
nY = pSPRRAM[ SPR_Y ] + 1;
if ( nY > PPU_Scanline || nY + PPU_SP_Height <= PPU_Scanline )
continue; /* Next sprite */
/*-------------------------------------------------------------------*/
/* A sprite in scanning line */
/*-------------------------------------------------------------------*/
/* Holizontal Sprite Count +1 */
++nSprCnt;
nAttr = pSPRRAM[ SPR_ATTR ];
nYBit = PPU_Scanline - nY;
nYBit = ( nAttr & SPR_ATTR_V_FLIP ) ? ( PPU_SP_Height - nYBit - 1 ) << 3 : nYBit << 3;
if ( PPU_R0 & R0_SP_SIZE )
{
/* Sprite size 8x16 */
if ( pSPRRAM[ SPR_CHR ] & 1 )
{
pbyChrData = ChrBuf + 256 * 64 + ( ( pSPRRAM[ SPR_CHR ] & 0xfe ) << 6 ) + nYBit;
}
else
{
pbyChrData = ChrBuf + ( ( pSPRRAM[ SPR_CHR ] & 0xfe ) << 6 ) + nYBit;
}
}
else
{
/* Sprite size 8x8 */
pbyChrData = PPU_SP_Base + ( pSPRRAM[ SPR_CHR ] << 6 ) + nYBit;
}
nAttr ^= SPR_ATTR_PRI;
bySprCol = ( nAttr & ( SPR_ATTR_COLOR | SPR_ATTR_PRI ) ) << 2;
nX = pSPRRAM[ SPR_X ];
if ( nAttr & SPR_ATTR_H_FLIP )
{
/* Horizontal flip */
if ( pbyChrData[ 7 ] )
pSprBuf[ nX ] = bySprCol | pbyChrData[ 7 ];
if ( pbyChrData[ 6 ] )
pSprBuf[ nX + 1 ] = bySprCol | pbyChrData[ 6 ];
if ( pbyChrData[ 5 ] )
pSprBuf[ nX + 2 ] = bySprCol | pbyChrData[ 5 ];
if ( pbyChrData[ 4 ] )
pSprBuf[ nX + 3 ] = bySprCol | pbyChrData[ 4 ];
if ( pbyChrData[ 3 ] )
pSprBuf[ nX + 4 ] = bySprCol | pbyChrData[ 3 ];
if ( pbyChrData[ 2 ] )
pSprBuf[ nX + 5 ] = bySprCol | pbyChrData[ 2 ];
if ( pbyChrData[ 1 ] )