fceugx/source/fceultra/boards/coolboy.cpp
2022-06-15 19:58:04 -06:00

214 lines
6.8 KiB
C++

/* FCE Ultra - NES/Famicom Emulator
*
* Copyright notice for this file:
* Copyright (C) 2018 CaH4e3, Cluster
*
* 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 program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* SMD132 and SMD133 ASICs, MMC3 clones that can address up to 32 MiB of PRG-ROM, 256 KiB of CHR-RAM, and 8 KiB of WRAM.
*
* COOLBOY cartridges use registers at address $6xxx
* MINDKIDS cartridges use a solder pad labelled "5/6K" to select between $5000 and $6000
*
* $xxx0
* 7 bit 0
* ---- ----
* ABCC DEEE
* |||| ||||
* |||| |+++-- PRG offset (PRG A19, A18, A17)
* |||| +----- Alternate CHR A17
* ||++------- PRG offset (PRG A24, A23)
* |+--------- PRG mask (PRG A17 from 0: MMC3; 1: offset)
* +---------- CHR mask (CHR A17 from 0: MMC3; 1: alternate)
*
* $xxx1
*
* 7 bit 0
* ---- ----
* GHIJ KKLx
* |||| |||
* |||| ||+--- GNROM mode bank PRG size (1: 32 KiB bank, PRG A14=CPU A14; 0: 16 KiB bank, PRG A14=offset A14)
* |||+-++---- PRG offset (in order: PRG A20, A22, A21)
* ||+-------- PRG mask (PRG A20 from 0: offset; 1: MMC3)
* |+--------- PRG mask (PRG A19 from 0: offset; 1: MMC3)
* +---------- PRG mask (PRG A18 from 0: MMC3; 1: offset)
*
* $xxx2
* 7 bit 0
* ---- ----
* xxxx MMMM
* ||||
* ++++-- CHR offset for GNROM mode (CHR A16, A15, A14, A13)
*
* $xxx3
* 7 bit 0
* ---- ----
* NPxP QQRx
* || | |||
* || | +++--- PRG offset for GNROM mode (PRG A16, A15, A14)
* || +------- 1: GNROM mode; 0: MMC3 mode
* || | (1: PRG A16...13 from QQ, L, R, CPU A14, A13 + CHR A16...10 from MMMM, PPU A12...10;
* || | 0: PRG A16...13 from MMC3 + CHR A16...A10 from MMC3 )
* |+-+------- Banking mode
* |+--------- "Weird MMC3 mode"
* +---------- Lockout (prevent further writes to these four registers, only works in MMC3 mode)
*
* Also some new cartridges from MINDKIDS have /WE and /OE pins connected to mapper,
* which allows you to rewrite flash memory without soldering.
* This also allows console to write data to the cartridge.
* This behavior is not emulated.
* No cart has been discovered so far that makes use of this feature, but this can be used for homebrew.
*
*/
#include "mapinc.h"
#include "mmc3.h"
static void COOLBOYCW(uint32 A, uint8 V) {
uint32 mask = 0xFF ^ (EXPREGS[0] & 0x80);
if (EXPREGS[3] & 0x10) {
if (EXPREGS[3] & 0x40) { // Weird mode
int cbase = (MMC3_cmd & 0x80) << 5;
switch (cbase ^ A) { // Don't even try do understand
case 0x0400:
case 0x0C00: V &= 0x7F; break;
}
}
// Highest bit goes from MMC3 registers when EXPREGS[3]&0x80==0 or from EXPREGS[0]&0x08 otherwise
setchr1(A,
(V & 0x80 & mask) | ((((EXPREGS[0] & 0x08) << 4) & ~mask)) // 7th bit
| ((EXPREGS[2] & 0x0F) << 3) // 6-3 bits
| ((A >> 10) & 7) // 2-0 bits
);
} else {
if (EXPREGS[3] & 0x40) { // Weird mode, again
int cbase = (MMC3_cmd & 0x80) << 5;
switch (cbase ^ A) { // Don't even try do understand
case 0x0000: V = DRegBuf[0]; break;
case 0x0800: V = DRegBuf[1]; break;
case 0x0400:
case 0x0C00: V = 0; break;
}
}
// Simple MMC3 mode
// Highest bit goes from MMC3 registers when EXPREGS[3]&0x80==0 or from EXPREGS[0]&0x08 otherwise
setchr1(A, (V & mask) | (((EXPREGS[0] & 0x08) << 4) & ~mask));
}
}
static void COOLBOYPW(uint32 A, uint8 V) {
uint32 mask = ((0x3F | (EXPREGS[1] & 0x40) | ((EXPREGS[1] & 0x20) << 2)) ^ ((EXPREGS[0] & 0x40) >> 2)) ^ ((EXPREGS[1] & 0x80) >> 2);
uint32 base = ((EXPREGS[0] & 0x07) >> 0) | ((EXPREGS[1] & 0x10) >> 1) | ((EXPREGS[1] & 0x0C) << 2) | ((EXPREGS[0] & 0x30) << 2);
// Very weird mode
// Last banks are first in this mode, ignored when MMC3_cmd&0x40
if ((EXPREGS[3] & 0x40) && (V >= 0xFE) && !((MMC3_cmd & 0x40) != 0)) {
switch (A & 0xE000) {
case 0xC000:
case 0xE000:
V = 0;
break;
}
}
// Regular MMC3 mode, internal ROM size can be up to 2048kb!
if (!(EXPREGS[3] & 0x10))
setprg8(A, (((base << 4) & ~mask)) | (V & mask));
else { // NROM mode
mask &= 0xF0;
uint8 emask;
if ((((EXPREGS[1] & 2) != 0))) // 32kb mode
emask = (EXPREGS[3] & 0x0C) | ((A & 0x4000) >> 13);
else // 16kb mode
emask = EXPREGS[3] & 0x0E;
setprg8(A, ((base << 4) & ~mask) // 7-4 bits are from base (see below)
| (V & mask) // ... or from MM3 internal regs, depends on mask
| emask // 3-1 (or 3-2 when (EXPREGS[3]&0x0C is set) from EXPREGS[3]
| ((A & 0x2000) >> 13)); // 0th just as is
}
}
static DECLFW(COOLBOYWrite) {
if(A001B & 0x80)
CartBW(A,V);
// Deny any further writes when 7th bit is 1 AND 4th is 0
if ((EXPREGS[3] & 0x90) != 0x80) {
EXPREGS[A & 3] = V;
FixMMC3PRG(MMC3_cmd);
FixMMC3CHR(MMC3_cmd);
}
}
static void COOLBOYReset(void) {
MMC3RegReset();
EXPREGS[0] = EXPREGS[1] = EXPREGS[2] = EXPREGS[3] = 0;
FixMMC3PRG(MMC3_cmd);
FixMMC3CHR(MMC3_cmd);
}
static void COOLBOYPower(void) {
GenMMC3Power();
EXPREGS[0] = EXPREGS[1] = EXPREGS[2] = EXPREGS[3] = 0;
FixMMC3PRG(MMC3_cmd);
FixMMC3CHR(MMC3_cmd);
SetWriteHandler(0x5000, 0x5fff, CartBW); // some games access random unmapped areas and crashes because of KT-008 PCB hack in MMC3 source lol
SetWriteHandler(0x6000, 0x6fff, COOLBOYWrite);
}
static void MINDKIDSPower(void) {
GenMMC3Power();
EXPREGS[0] = EXPREGS[1] = EXPREGS[2] = EXPREGS[3] = 0;
FixMMC3PRG(MMC3_cmd);
FixMMC3CHR(MMC3_cmd);
SetWriteHandler(0x5000, 0x5fff, COOLBOYWrite);
}
// Registers at $6xxx
void COOLBOY_Init(CartInfo *info) {
GenMMC3_Init(info, 2048, 256, 8, 1);
pwrap = COOLBOYPW;
cwrap = COOLBOYCW;
info->Power = COOLBOYPower;
info->Reset = COOLBOYReset;
AddExState(EXPREGS, 4, 0, "EXPR");
}
// Registers at $5xxx
void MINDKIDS_Init(CartInfo *info) {
GenMMC3_Init(info, 2048, 256, 8, 1);
pwrap = COOLBOYPW;
cwrap = COOLBOYCW;
info->Power = MINDKIDSPower;
info->Reset = COOLBOYReset;
AddExState(EXPREGS, 4, 0, "EXPR");
}
// For NES 2.0 loader
void SMD132_SMD133_Init(CartInfo *info) {
switch (info->submapper)
{
case 0:
COOLBOY_Init(info);
break;
case 1:
MINDKIDS_Init(info);
break;
default:
FCEU_PrintError("Unknown submapper: #%d.", info->submapper);
break;
}
}