MEGA65: better cartridge + new CRT support #380

lgblgblgb · lgblgblgb · commit b53140be9c66 · 2025-07-06T14:32:19.000+02:00
Still preliminary, no proper check of CRT files at every level, also no
bank support, no ROM/RAM support (everything is treated as ROM).

[DEPLOYMENT]
diff --git a/targets/mega65/cart.c b/targets/mega65/cart.c
@@ -1,6 +1,6 @@
 /* A work-in-progess MEGA65 (Commodore 65 clone origins) emulator
    Part of the Xemu project, please visit: https://github.com/lgblgblgb/xemu
-   Copyright (C)2016-2024 LGB (Gábor Lénárt) <lgblgblgb@gmail.com>
+   Copyright (C)2016-2025 LGB (Gábor Lénárt) <lgblgblgb@gmail.com>
 
 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
@@ -20,31 +20,45 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
 #include "cart.h"
 #include "xemu/emutools_files.h"
 #include "audio65.h"
+#include "string.h"
+#include "errno.h"
 
-static Uint8 cart_mem[0x10000];
-static int loaded = 0;
+
+static struct {
+	bool loaded;
+	bool autostart;
+	char *fn;
+	char name[0x21];
+	Uint8 mem[0x10000];
+	int total_size;
+	int sections;
+} cart;
 
 
 void cart_init ( void )
 {
-	memset(cart_mem, 0xFF, sizeof cart_mem);
+	memset(cart.mem, 0xFF, sizeof cart.mem);
+	cart.loaded = false;
+	cart.autostart = false;
+	cart.name[0] = 0;
+	cart.fn = NULL;
 }
 
 
 Uint8 cart_read_byte  ( unsigned int addr )
 {
 	Uint8 data = 0xFF;
-	if (addr < sizeof(cart_mem))
-		data = cart_mem[addr];
-	if (loaded && addr != 0x3FFDF60)	// see the comment about OPL at cart_write_byte()
-		DEBUGPRINT("CART: reading byte ($%02X) at $%X" NL, data, addr + 0x4000000);
+	if (addr < sizeof(cart.mem))
+		data = cart.mem[addr];
+	//if (cart.loaded && addr != 0x3FFDF60)	// see the comment about OPL at cart_write_byte()
+	//	DEBUGPRINT("CART: reading byte ($%02X) at $%X" NL, data, addr + 0x4000000);
 	return data;
 }
 
 
 void cart_write_byte ( unsigned int addr, Uint8 data )
 {
-	if (!loaded) {
+	if (!cart.loaded) {
 		// a hack OPL to be able to work in the "slow device area" [if no cartridge is loaded]
 		static Uint8 opl_reg_sel = 0;
 		if (addr == 0x3FFDF40) {
@@ -55,43 +69,138 @@ void cart_write_byte ( unsigned int addr, Uint8 data )
 			return;
 		}
 	}
-	DEBUGPRINT("CART: writing byte ($%02X) at $%X" NL, data, addr + 0x4000000);
+	//DEBUGPRINT("CART: writing byte ($%02X) at $%X" NL, data, addr + 0x4000000);
 }
 
 
-int cart_load_bin ( const char *fn, const unsigned int addr, const char *cry )
+bool cart_is_attached ( void )
 {
-	if (!fn || !*fn)
-		return 0;
-	loaded = 0;
-	if (addr >= sizeof(cart_mem)) {
-		if (cry)
-			ERROR_WINDOW("%s\nOutside of 64K range\n%s", cry, fn);
-		return -1;
+	return cart.loaded;
+}
+
+
+void cart_detach ( void )
+{
+	memset(cart.mem, 0xFF, sizeof cart.mem);
+	cart.autostart = false;
+	free(cart.fn);
+	cart.fn = NULL;
+	if (cart.loaded) {
+		DEBUGPRINT("CART: cartridge has been detached" NL);
+		cart.loaded = false;
 	}
-	const int ret = xemu_load_file(fn, cart_mem + addr, 1, sizeof(cart_mem) - addr, cry);
-	if (ret <= 0)
-		return -1;
-	DEBUGPRINT("CART: %d byte(s) loaded at offset $%04X from file %s" NL, ret, addr, fn);
-	loaded = 1;
-	return 0;
 }
 
 
-int cart_detect_id ( void )
+static bool _check_cartridge_str ( const Uint8 *p )
 {
-	static const Uint8 cart_id[] = {'M', '6', '5'};
-	return memcmp(cart_mem + 0x8007, cart_id, sizeof cart_id);
+	static const char cartridge_bytestr[]	= { ' ', 'C', 'A', 'R', 'T', 'R', 'I', 'D', 'G', 'E' };
+	for (unsigned int a = 3; a < 7; a++)
+		if (!memcmp(p + a, cartridge_bytestr, sizeof cartridge_bytestr))
+			return true;
+	return false;
 }
 
 
-int cart_is_loaded ( void )
+int cart_attach ( const char *fn )
 {
-	return loaded;
+	static const char m65_bytestr[]		= { 'M', '6', '5' };
+	static const char mega65_bytestr[]	= { 'M', 'E', 'G', 'A', '6', '5' };
+	static const char chip_bytestr[]	= { 'C', 'H', 'I', 'P' };
+	cart_detach();
+	if (!fn || !*fn)
+		return -1;
+	const int fd = xemu_open_file(fn, O_RDONLY, NULL, NULL);
+	if (fd < 0) {
+		ERROR_WINDOW("Cannot open cartridge file %s\nError: %s", fn, strerror(errno));
+		return -1;
+	}
+	cart.fn = xemu_realloc(cart.fn, strlen(fn) + 1);
+	strcpy(cart.fn, fn);
+	Uint8 buf[0x40 + 1];
+	if (xemu_safe_read(fd, buf, 0x40) != 0x40)
+		goto read_error;
+	if (!_check_cartridge_str(buf)) {
+		// " CARTRIDGE" (with space) cannot be found in the first 0x10 bytes: not a VICE CRT format
+		// let's check if it's a "raw ROM" with the "M65" mark
+		if (memcmp(buf + 7, m65_bytestr, sizeof m65_bytestr)) {
+			ERROR_WINDOW("Not a CRT/raw file: %s", fn);	// not that either -> error
+			goto error;
+		}
+		// Raw binary file, with "M65" mark: the best I can do is loading from $8000
+		memcpy(cart.mem + 0x8000, buf, 0x40);	// copy what we have already
+		const int ret = xemu_safe_read(fd, cart.mem + 0x8000 + 0x40, 0x10000 - 0x8000 - 0x40);	// load the rest
+		if (ret < 0)
+			goto read_error;
+		cart.loaded = true;
+		cart.sections = 0;
+		cart.total_size = ret + 0x40;
+		cart.autostart = true;	// raw image is always auto start as I detected with 'M65' signature ...
+		DEBUGPRINT("CART: raw cartridge ROM image \"%s\" has been loaded to $8000-$%X" NL, fn, 0x8000 + cart.total_size - 1);
+		close(fd);
+		return 1;
+	}
+	if (memcmp(buf, mega65_bytestr, sizeof mega65_bytestr)) {
+		ERROR_WINDOW("Non-MEGA65 CRT file: %s", fn);
+		goto error;
+	}
+	// VICE-like CRT file (MEGA65-specific though)
+	DEBUGPRINT("CART: trying to attach VICE-like CRT file %s" NL, fn);
+	buf[0x40] = 0;
+	strcpy(cart.name, (const char*)buf + 0x20);
+	cart.sections = 0;
+	cart.total_size = 0;
+	for (;;) {
+		const int ret = xemu_safe_read(fd, buf, 0x10);	// read "CHIP" section header
+		if (!ret)
+			break;
+		if (ret != 0x10)
+			goto read_error;
+		if (memcmp(buf, chip_bytestr, sizeof chip_bytestr)) {
+			ERROR_WINDOW("Bad CRT file, missing CHIP section ID");
+			goto error;
+		}
+		const unsigned int size = (buf[0xE] << 8) + buf[0xF];
+		const unsigned int addr = (buf[0xC] << 8) + buf[0xD];
+		DEBUGPRINT("CART: ... new CHIP section (#%d), $%04X-$%04X (%u bytes)" NL, cart.sections, addr, addr + size - 1, size);
+		if (size + addr > 0x10000) {
+			ERROR_WINDOW("Bad CRT file, CHIP section overflows memory");
+			goto error;
+		}
+		if (size) {
+			if (xemu_safe_read(fd, cart.mem + addr, size) != size)
+				goto read_error;
+		}
+		cart.sections++;
+		cart.total_size += size;
+	}
+	if (!cart.sections) {
+		ERROR_WINDOW("No CHIP sections");
+		goto error;
+	}
+	cart.loaded = true;
+	cart.autostart = !memcmp(cart.mem + 0x8007, m65_bytestr, sizeof m65_bytestr);
+	DEBUGPRINT("CART: attached, autostart = %d, name = \"%s\"" NL, (int)cart.autostart, cart.name);
+	close(fd);
+	return (int)cart.autostart;
+read_error:
+	ERROR_WINDOW("Cannot read (or truncated/too small) cartridge file %s", fn);
+error:
+	cart_detach();
+	if (fd >= 0)
+		close(fd);
+	return -1;
 }
 
 
-void cart_copy_from ( const Uint16 cart_addr, Uint8 *target, const Uint16 size )
+void cart_info ( char *p, size_t size )
 {
-	memcpy(target, cart_mem + cart_addr, size);
+	if (!cart.loaded) {
+		snprintf(p, size, "No cartridge is attached");
+		return;
+	}
+	snprintf(p, size, "Filename: %s\nCartridge: %s\nAuto-start: %d\nSections: %d\nTotal binary size: %d\nFormat: %s",
+		cart.fn, cart.name, (int)cart.autostart, cart.sections, cart.total_size,
+		cart.sections ? "CRT" : "RAW"
+	);
 }
diff --git a/targets/mega65/cart.h b/targets/mega65/cart.h
@@ -1,6 +1,6 @@
 /* A work-in-progess MEGA65 (Commodore 65 clone origins) emulator
    Part of the Xemu project, please visit: https://github.com/lgblgblgb/xemu
-   Copyright (C)2016-2024 LGB (Gábor Lénárt) <lgblgblgb@gmail.com>
+   Copyright (C)2016-2025 LGB (Gábor Lénárt) <lgblgblgb@gmail.com>
 
 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
@@ -19,12 +19,12 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
 #ifndef XEMU_MEGA65_CART_H_INCLUDED
 #define XEMU_MEGA65_CART_H_INCLUDED
 
-extern void  cart_init       ( void );
-extern Uint8 cart_read_byte  ( unsigned int addr );
-extern void  cart_write_byte ( unsigned int addr, Uint8 data );
-extern int   cart_load_bin   ( const char *fn, const unsigned int addr, const char *cry );
-extern void  cart_copy_from  ( const Uint16 cart_addr, Uint8 *target, const Uint16 size );
-extern int   cart_detect_id  ( void );
-extern int   cart_is_loaded  ( void );
+extern void  cart_init        ( void );
+extern Uint8 cart_read_byte   ( unsigned int addr );
+extern void  cart_write_byte  ( unsigned int addr, Uint8 data );
+extern int   cart_attach      ( const char *fn );
+extern void  cart_detach      ( void );
+extern bool  cart_is_attached ( void );
+extern void  cart_info        ( char *p, size_t size );
 
 #endif
diff --git a/targets/mega65/configdb.c b/targets/mega65/configdb.c
@@ -74,7 +74,7 @@ static const struct xemutools_configdef_str_st str_options[] = {
 #endif
 	{ "gui",	NULL, "Select GUI type for usage. Specify some insane str to get a list", &configdb.selectedgui },
 	{ "importbas",	NULL, "Import and RUN BASIC65 program from TEXT file", &configdb.importbas },
-	{ "cartbin8000",NULL, "Load binary cartridge image from $8000", &configdb.cartbin8000 },
+	{ "cart",	NULL, "Load cartridge file", &configdb.cart },
 	{ "winpos",	NULL, "Window position: x,y (integers)", &configdb.winpos },
 	{ "initattic",	NULL, "Pre-fill the Attic RAM with the content of a file", &configdb.init_attic },
 	{ NULL }
@@ -164,7 +164,7 @@ static const void *do_not_save_opts[] = {
 	&configdb.screenshot_and_exit,
 #endif
 	&configdb.testing, &configdb.hyperdebug, &configdb.hyperdebugfreezer, &configdb.usestubrom, &configdb.useinitrom, &configdb.useutilmenu,
-	&configdb.cartbin8000, &configdb.winpos, &configdb.ramcheckread, &configdb.init_attic,
+	&configdb.cart, &configdb.winpos, &configdb.ramcheckread, &configdb.init_attic,
 	&configdb.prg_test, &configdb.prg_exit,
 	NULL
 };
diff --git a/targets/mega65/configdb.h b/targets/mega65/configdb.h
@@ -97,7 +97,7 @@ struct configdb_st {
 	// $60/$61/$62 = qmtecha100t/qmtecha200t/qmtecha325t, $21/$22=megaphoner1/megaphoner4
 	int	mega65_model;
 	int	colour_effect;
-	char	*cartbin8000;
+	char	*cart;
 	int	hicked;
 	int	prgmode;
 	int	rtc_hour_offset;
diff --git a/targets/mega65/mega65.c b/targets/mega65/mega65.c
@@ -363,7 +363,7 @@ static void mega65_init ( void )
 	} while (0);
 	// *** Initializes memory subsystem of MEGA65 emulation itself
 	memory_init();
-	cart_load_bin(configdb.cartbin8000, 0x8000, "Cannot load binary cartridge image from $8000");
+	cart_attach(configdb.cart);
 	if (xemu_load_file(I2C_FILE_NAME, i2c_regs, sizeof i2c_regs, sizeof i2c_regs,
 #ifndef		XEMU_ARCH_HTML
 		"Cannot load I2C reg-space. Maybe first run or upgrade of Xemu?\nFor the next Xemu launch, it should have been already corrected automatically.\nSo no need to worry."
@@ -564,6 +564,8 @@ int reset_mega65 ( const unsigned int options )
 		if (!ARE_YOU_SURE("Are you sure you want to RESET your emulated machine?", i_am_sure_override | ARE_YOU_SURE_DEFAULT_YES))
 			return 0;
 	}
+	if ((options & RESET_MEGA65_NO_CART))
+		cart_detach();
 	switch (options & 0xFF) {
 		case RESET_MEGA65_HARD:
 			last_reset_type = "HARD";
diff --git a/targets/mega65/mega65.h b/targets/mega65/mega65.h
@@ -59,6 +59,7 @@ extern void machine_set_speed ( int verbose );
 #define RESET_MEGA65_HYPPO	0x003
 #define RESET_MEGA65_LAST_ID	RESET_MEGA65_HYPPO
 #define RESET_MEGA65_ASK	0x100
+#define RESET_MEGA65_NO_CART	0x200
 extern int  reset_mega65 ( const unsigned int options );
 
 extern int  mega65_set_model ( const Uint8 id );
diff --git a/targets/mega65/ui.c b/targets/mega65/ui.c
