snes.c: detect SNES ROM type

Need a small core change, too
2026-04-25 03:55:33 +00:00 · 2024-09-21 22:44:33 +02:00
parent 5541297e77
commit 2102ac4431
6 changed files with 208 additions and 3 deletions
--- a/2
+++ b/2
@@ -11,7 +11,7 @@ TODAY = `date +"%m/%d/%y"`

 PRJ = firmware
 SRC = hw/AT91SAM/Cstartup_SAM7.c hw/AT91SAM/hardware.c hw/AT91SAM/spi.c hw/AT91SAM/mmc.c hw/AT91SAM/at91sam_usb.c hw/AT91SAM/usbdev.c
-SRC += fdd.c  firmware.c  fpga.c hdd.c  main.c  menu.c menu-minimig.c menu-8bit.c osd.c state.c syscalls.c user_io.c settings.c data_io.c boot.c idxfile.c config.c tos.c ikbd.c xmodem.c ini_parser.c cue_parser.c mist_cfg.c archie.c pcecd.c neocd.c arc_file.c font.c utils.c
+SRC += fdd.c  firmware.c  fpga.c hdd.c  main.c  menu.c menu-minimig.c menu-8bit.c osd.c state.c syscalls.c user_io.c settings.c data_io.c boot.c idxfile.c config.c tos.c ikbd.c xmodem.c ini_parser.c cue_parser.c mist_cfg.c archie.c pcecd.c neocd.c snes.c arc_file.c font.c utils.c
 SRC += usb/usb.c usb/max3421e.c usb/usb-max3421e.c usb/usbdebug.c usb/hub.c usb/hid.c usb/hidparser.c usb/xboxusb.c usb/timer.c usb/asix.c usb/pl2303.c usb/usbrtc.c usb/storage.c usb/joymapping.c usb/joystick.c
 SRC += fat_compat.c
 SRC += FatFs/diskio.c FatFs/ff.c FatFs/ffunicode.c
--- a/Makefile.SAMV71
+++ b/Makefile.SAMV71
@@ -12,7 +12,7 @@ TODAY = `date +"%m/%d/%y"`
 PRJ = firmware
 SRC = hw/ATSAMV71/cstartup.c hw/ATSAMV71/hardware.c hw/ATSAMV71/spi.c hw/ATSAMV71/qspi.c hw/ATSAMV71/mmc.c hw/ATSAMV71/usbdev.c  hw/ATSAMV71/eth.c hw/ATSAMV71/irq/nvic.c
 SRC += hw/ATSAMV71/network/intmath.c hw/ATSAMV71/network/gmac.c hw/ATSAMV71/network/gmacd.c hw/ATSAMV71/network/phy.c hw/ATSAMV71/network/ethd.c
-SRC += fdd.c firmware.c fpga.c hdd.c  main.c  menu.c menu-minimig.c menu-8bit.c osd.c state.c syscalls.c user_io.c settings.c data_io.c boot.c idxfile.c config.c tos.c ikbd.c xmodem.c ini_parser.c cue_parser.c mist_cfg.c archie.c pcecd.c neocd.c psx.c arc_file.c font.c utils.c
+SRC += fdd.c firmware.c fpga.c hdd.c  main.c  menu.c menu-minimig.c menu-8bit.c osd.c state.c syscalls.c user_io.c settings.c data_io.c boot.c idxfile.c config.c tos.c ikbd.c xmodem.c ini_parser.c cue_parser.c mist_cfg.c archie.c pcecd.c neocd.c psx.c snes.c arc_file.c font.c utils.c
 SRC += it6613/HDMI_TX.c it6613/it6613_drv.c it6613/it6613_sys.c it6613/EDID.c it6613/hdmitx_mist.c
 SRC += usb/usbdebug.c usb/hub.c usb/xboxusb.c usb/hid.c usb/hidparser.c usb/timer.c usb/asix.c usb/pl2303.c usb/usbrtc.c usb/joymapping.c usb/joystick.c usb/storage.c
 SRC += usb/usb.c usb/max3421e.c usb/usb-max3421e.c
--- a/debug.h
+++ b/debug.h
@@ -161,6 +161,13 @@
 #define psx_debugf(...)
 #endif

+#if 0
+// SNES debug output
+#define snes_debugf(a, ...) iprintf("\033[1;34mSNES : " a "\033[0m\n",## __VA_ARGS__)
+#else
+#define snes_debugf(...)
+#endif
+
 #if 1
 // HDMI debug output
 #define hdmi_debugf(a, ...) iprintf("\033[1;34mHDMI : " a "\033[0m",## __VA_ARGS__)
--- a/menu-8bit.c
+++ b/menu-8bit.c
@@ -28,6 +28,7 @@
 #include "data_io.h"
 #include "fat_compat.h"
 #include "cue_parser.h"
+#include "snes.h"

 extern char s[FF_LFN_BUF + 1];

@@ -39,6 +40,7 @@ extern char fs_pFileExt[13];
 /////// 8-bit menu ///////
 //////////////////////////
 static unsigned char selected_drive_slot;
+static unsigned char isSnesROM;


 static void substrcpy(char *d, char *s, char idx) {
@@ -116,9 +118,11 @@ static unsigned long long getStatusMask(char *opt) {

 static char RomFileSelected(uint8_t idx, const char *SelectedName) {
 	FIL file;
+	char snes_romtype;
 	// this assumes that further file entries only exist if the first one also exists
 	if (f_open(&file, SelectedName, FA_READ) == FR_OK) {
-		data_io_file_tx(&file, user_io_ext_idx(SelectedName, fs_pFileExt)<<6 | selected_drive_slot, GetExtension(SelectedName));
+		if (isSnesROM) snes_romtype = snes_getromtype(&file);
+		data_io_file_tx(&file, (isSnesROM ? snes_romtype : user_io_ext_idx(SelectedName, fs_pFileExt))<<6 | selected_drive_slot, GetExtension(SelectedName));
 		f_close(&file);
 	}
 	// close menu afterwards
@@ -192,6 +196,7 @@ static char GetMenuItem_8bit(uint8_t idx, char action, menu_item_t *item) {
 				strncpy(ext, p, 13);
 				while(strlen(ext) < 3) strcat(ext, " ");
 				selected_drive_slot = 1;
+				isSnesROM = 0;
 				SelectFileNG(ext, SCAN_DIR | SCAN_LFN, RomFileSelected, 1);
 			} else if (action == MENU_ACT_GET) {
 				//menumask = 1;
@@ -244,6 +249,8 @@ static char GetMenuItem_8bit(uint8_t idx, char action, menu_item_t *item) {
 				iscue = 1;
 			}
 			if (p[1]>='0' && p[1]<='9') selected_drive_slot = p[1]-'0';
+			isSnesROM = 0;
+			if (p[1] && p[1] != ',' && p[2] && p[2] != ',' && !strncmp(&p[2], "SNES", 4)) isSnesROM = 1; // F1SNES
 			substrcpy(ext, p, 1);
 			while(strlen(ext) < 3) strcat(ext, " ");
 			SelectFileNG(ext, SCAN_DIR | SCAN_LFN, (p[0] == 'F')?RomFileSelected:iscue?CueFileSelected:ImageFileSelected, 1);
--- a/snes.c
+++ b/snes.c
@@ -0,0 +1,166 @@
+/*
+  This file is part of MiST-firmware
+
+  MiST-firmware 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 3 of the License, or
+  (at your option) any later version.
+
+  MiST-firmware 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, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <stdint.h>
+#include <stdio.h>
+#include "snes.h"
+#include "fat_compat.h"
+#include "debug.h"
+
+enum HeaderField {
+	CartName = 0x00,
+	Mapper = 0x15,
+	RomType = 0x16,
+	RomSize = 0x17,
+	RamSize = 0x18,
+	CartRegion = 0x19,
+	Company = 0x1a,
+	Version = 0x1b,
+	Complement = 0x1c,  //inverse checksum
+	Checksum = 0x1e,
+	ResetVector = 0x3c,
+};
+
+// From Main_MiSTer/support/snes/snes.cpp
+static uint32_t score_header(FIL *file, uint32_t offset, uint32_t addr)
+{
+	int score = 0;
+	UINT br;
+	uint8_t *data = sector_buffer;
+
+	snes_debugf("Header address: %08x offset: %d", addr, offset);
+
+	if ((f_lseek(file, offset + addr) != FR_OK) ||
+	    (f_tell(file) != (offset + addr)) ||
+	    (f_read(file, data, 64, &br) != FR_OK)) {
+		return 0;
+	}
+
+	uint16_t resetvector = data[ResetVector] | (data[ResetVector + 1] << 8);
+	uint16_t checksum = data[Checksum] | (data[Checksum + 1] << 8);
+	uint16_t complement = data[Complement] | (data[Complement + 1] << 8);
+
+	snes_debugf("Reset vector: %04x, checksum: %04x, complement: %04x", resetvector, checksum, complement);
+
+	//$00:[0000-7fff] contains uninitialized RAM and MMIO.
+	//reset vector must point to ROM at $00:[8000-ffff] to be considered valid.
+	if (resetvector < 0x8000) return 0;
+
+	uint8_t resetop = 0;
+	if (f_lseek(file, ((addr & ~0x7fff) | (resetvector & 0x7fff)) + offset ) != FR_OK) return 0;
+	if (f_read(file, &resetop, 1, &br) != FR_OK) return 0;
+	//uint8_t resetop = data[(addr & ~0x7fff) | (resetvector & 0x7fff)];  //first opcode executed upon reset
+	uint8_t mapper = data[Mapper] & ~0x10;                      //mask off irrelevent FastROM-capable bit
+
+	//some images duplicate the header in multiple locations, and others have completely
+	//invalid header information that cannot be relied upon.
+	//below code will analyze the first opcode executed at the specified reset vector to
+	//determine the probability that this is the correct header.
+
+	//most likely opcodes
+	if (resetop == 0x78  //sei
+		|| resetop == 0x18  //clc (clc; xce)
+		|| resetop == 0x38  //sec (sec; xce)
+		|| resetop == 0x9c  //stz $nnnn (stz $4200)
+		|| resetop == 0x4c  //jmp $nnnn
+		|| resetop == 0x5c  //jml $nnnnnn
+		) score += 8;
+
+	//plausible opcodes
+	if (resetop == 0xc2  //rep #$nn
+		|| resetop == 0xe2  //sep #$nn
+		|| resetop == 0xad  //lda $nnnn
+		|| resetop == 0xae  //ldx $nnnn
+		|| resetop == 0xac  //ldy $nnnn
+		|| resetop == 0xaf  //lda $nnnnnn
+		|| resetop == 0xa9  //lda #$nn
+		|| resetop == 0xa2  //ldx #$nn
+		|| resetop == 0xa0  //ldy #$nn
+		|| resetop == 0x20  //jsr $nnnn
+		|| resetop == 0x22  //jsl $nnnnnn
+		) score += 4;
+
+	//implausible opcodes
+	if (resetop == 0x40  //rti
+		|| resetop == 0x60  //rts
+		|| resetop == 0x6b  //rtl
+		|| resetop == 0xcd  //cmp $nnnn
+		|| resetop == 0xec  //cpx $nnnn
+		|| resetop == 0xcc  //cpy $nnnn
+		) score -= 4;
+
+	//least likely opcodes
+	if (resetop == 0x00  //brk #$nn
+		|| resetop == 0x02  //cop #$nn
+		|| resetop == 0xdb  //stp
+		|| resetop == 0x42  //wdm
+		|| resetop == 0xff  //sbc $nnnnnn,x
+		) score -= 8;
+
+	//at times, both the header and reset vector's first opcode will match ...
+	//fallback and rely on info validity in these cases to determine more likely header.
+
+	//a valid checksum is the biggest indicator of a valid header.
+	if ((checksum + complement) == 0xffff && (checksum != 0) && (complement != 0)) score += 4;
+
+
+	if (addr == 0x007fc0 && mapper == 0x20) score += 2;  //0x20 is usually LoROM
+	if (addr == 0x00ffc0 && mapper == 0x21) score += 2;  //0x21 is usually HiROM
+	if (addr == 0x007fc0 && mapper == 0x22) score += 2;  //0x22 is usually SDD1
+	if (addr == 0x40ffc0 && mapper == 0x25) score += 2;  //0x25 is usually ExHiROM
+
+	if (data[Company] == 0x33) score += 2;        //0x33 indicates extended header
+	if (data[RomType] < 0x08) score++;
+	if (data[RomSize] < 0x10) score++;
+	if (data[RamSize] < 0x08) score++;
+	if (data[CartRegion] < 14) score++;
+
+	snes_debugf("Resetop: %02x mapper: %02x score: %d",
+	    resetop, mapper, score);
+
+	if (score < 0) score = 0;
+	return score;
+}
+
+char snes_getromtype(FIL *file)
+{
+	uint32_t score_lo, score_hi, score_ex;
+	UINT br;
+	FSIZE_t size = f_size(file);
+	FSIZE_t offset = size & 0x1ff;
+
+	score_lo = score_header(file, offset, (FSIZE_t) 0x007fc0);
+	score_hi = score_header(file, offset, (FSIZE_t) 0x00ffc0);
+	score_ex = score_header(file, offset, (FSIZE_t) 0x40ffc0);
+	f_rewind(file);
+
+	if (score_ex) score_ex += 4;  //favor ExHiROM on images > 32mbits
+	if (score_lo >= score_hi && score_lo >= score_ex) {
+		iprintf("Detected LoROM\n");
+		return 0; // probably LoROM
+	}
+	if (score_hi >= score_ex) {
+		iprintf("Detected HiROM\n");
+		return 1; // probably HiROM
+	}
+	if (score_ex) {
+		iprintf("Detected ExHiROM\n");
+		return 2; // probably ExHiROM
+	}
+	iprintf("No clue about ROM type\n");
+	return 0; // no idea, fall back to LoROM
+}
--- a/snes.h
+++ b/snes.h
@@ -0,0 +1,25 @@
+/*
+  This file is part of MiST-firmware
+
+  MiST-firmware 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 3 of the License, or
+  (at your option) any later version.
+
+  MiST-firmware 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, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef SNES_H
+#define SNES_H
+
+#include "FatFs/ff.h"
+
+char snes_getromtype(FIL *file);
+
+#endif // SNES_H