emulator uses a bus now in the cpu, ROM, RAM and VIA (7-seg) are devices connected to the bus

14 files changed, 314 insertions, 78 deletions

diff --git a/emu/6502.c b/emu/6502.c
index ce1f0d3..dbdf5a1 100644
--- a/emu/6502.c
+++ b/emu/6502.c
@@ -8,9 +8,9 @@ static const uint16_t reset_vector = 0xFFFC;
 static const uint16_t ZP_base = 0x0;
 static const uint16_t SP_base = 0x100;
 
-void cpu_6502_init( cpu_6502_t *cpu, struct memory_t *memory )
+void cpu_6502_init( cpu_6502_t *cpu, bus_t *bus )
 {
-	cpu->memory = memory;
+	cpu->bus = bus;
 	cpu->debug_flags = 0;
 }
 
@@ -62,18 +62,18 @@ void cpu_6502_reset( cpu_6502_t *cpu )
 
 uint8_t cpu_6502_read_byte( cpu_6502_t *cpu, uint16_t addr )
 {
-	return cpu->memory->read( cpu->memory, addr );
+	return cpu->bus->base.vtable->read( cpu->bus, addr );
 }
 
 void cpu_6502_write_byte( cpu_6502_t *cpu, uint16_t addr, uint8_t data )
 {
-	cpu->memory->write( cpu->memory, addr, data );
+	cpu->bus->base.vtable->write( cpu->bus, addr, data );
 }
 
 void cpu_6502_write_word( cpu_6502_t *cpu, uint16_t addr, uint16_t data )
 {
-	cpu->memory->write( cpu->memory, addr, ( data && 0x00FF ) );
-	cpu->memory->write( cpu->memory, addr + 1, ( data && 0x00FF ) );
+	cpu->bus->base.vtable->write( cpu->bus, addr, ( data && 0x00FF ) );
+	cpu->bus->base.vtable->write( cpu->bus, addr + 1, ( data && 0x00FF ) );
 }
 
 void cpu_6502_run( cpu_6502_t *cpu, int steps )
diff --git a/emu/6502.h b/emu/6502.h
index 20574c3..22da89f 100644
--- a/emu/6502.h
+++ b/emu/6502.h
@@ -4,6 +4,8 @@
 #include <inttypes.h>
 #include <stdbool.h>
 
+#include "bus.h"
+
 typedef struct
 {
 	uint8_t A;
@@ -13,7 +15,7 @@ typedef struct
 	uint16_t PC;
 	uint8_t PS;
 	
-	struct memory_t *memory;
+	bus_t *bus;
 	
 	int debug_flags;
 	
@@ -57,7 +59,7 @@ enum {
 	TXS_IMPL = 0x9A
 };
 
-void cpu_6502_init( cpu_6502_t *cpu, struct memory_t *memory );
+void cpu_6502_init( cpu_6502_t *cpu, bus_t *bus );
 void cpu_6502_reset( cpu_6502_t *cpu );
 uint8_t cpu_6502_read_byte( cpu_6502_t *cpu, uint16_t addr );
 uint16_t cpu_6502_read_word( cpu_6502_t *cpu, uint16_t addr );
diff --git a/emu/7seg.c b/emu/7seg.c
index 1aaf5f9..04a37f5 100644
--- a/emu/7seg.c
+++ b/emu/7seg.c
@@ -2,19 +2,31 @@
 
 #include <stdio.h>
 
-void seg7_init( seg7_t *seg )
+static device_vtable_t const seg7_vtable = {
+	seg7_read,
+	seg7_write,
+	seg7_deinit
+};
+
+void seg7_init( seg7_t *seg, uint16_t addr )
 {
+	device_init( &seg->base, "seg7" );
+	seg->base.vtable = (device_vtable_t *)&seg7_vtable;
+
+	seg->addr = addr;
 	seg->debug = false;
 }
 
-uint8_t seg7_read( seg7_t *seg, uint16_t addr )
+uint8_t seg7_read( void *obj, uint16_t addr )
 {
 	return 0;
 }
 
-void seg7_write( seg7_t *seg, uint16_t addr, uint8_t data )
+void seg7_write( void *obj, uint16_t addr, uint8_t data )
 {
-	switch( addr ) {
+	seg7_t *seg = (seg7_t *)obj;
+	
+	switch( addr - seg->addr ) {
 		case DDRA:
 			seg->ddr = data;
 			break;
@@ -41,3 +53,10 @@ void seg7_write( seg7_t *seg, uint16_t addr, uint8_t data )
 		// ignore writes to other addresses
 	}
 }
+
+void seg7_deinit( void *obj )
+{
+	seg7_t *seg = (seg7_t *)obj;
+
+	device_deinit( &seg->base );
+}
diff --git a/emu/7seg.h b/emu/7seg.h
index 0cd585f..3953c70 100644
--- a/emu/7seg.h
+++ b/emu/7seg.h
@@ -1,6 +1,8 @@
 #ifndef SEG7_H
 #define SEG7_H
 
+#include "device.h"
+
 #ifdef WITH_GUI
 #include <SDL.h>
 #endif
@@ -18,8 +20,8 @@
 //       +---- RCLK
 //      +----- SRCLK
 enum {
-	PORTA = 0x6001,
-	DDRA  = 0x6003,
+	PORTA = 0x01,
+	DDRA  = 0x03,
 	
 	SER   = 0x01,
 	RCLK  = 0x02,
@@ -28,6 +30,10 @@ enum {
 
 typedef struct seg7_t
 {
+	device_t base;
+	
+	uint16_t addr;
+	
 	uint8_t ddr;
 	uint16_t shift;
 	uint16_t latch;
@@ -35,8 +41,10 @@ typedef struct seg7_t
 	bool debug;
 } seg7_t;
 
-void seg7_init( seg7_t *seg );
-uint8_t seg7_read( seg7_t *seg, uint16_t addr );
-void seg7_write( seg7_t *seg, uint16_t addr, uint8_t data );
+void seg7_init( seg7_t *seg, uint16_t addr );
+
+uint8_t seg7_read( void *obj, uint16_t addr );
+void seg7_write( void *obj, uint16_t addr, uint8_t data );
+void seg7_deinit( void *obj );
 
 #endif
diff --git a/emu/CMakeLists.txt b/emu/CMakeLists.txt
index e1fe6c9..04b1788 100644
--- a/emu/CMakeLists.txt
+++ b/emu/CMakeLists.txt
@@ -8,7 +8,7 @@ project(emu C)
 
 set( EMU_VERSION 0.0.1 )
 
-set(CMAKE_C_FLAGS "-g -O0 -std=c99 -Wall -DWITH_GUI")
+set(CMAKE_C_FLAGS "-g -O0 -std=c99 -Wall -DWITH_GUI -D_POSIX_C_SOURCE=200809L")
 
 add_custom_target(distclean
 	COMMAND make clean
@@ -21,6 +21,8 @@ configure_file( "${PROJECT_SOURCE_DIR}/version.h.in"
 	"${PROJECT_SOURCE_DIR}/version.h" @ONLY )
 
 set(SRC
+	device.c
+	bus.c
 	6502.c
 	memory.c
 	7seg.c
diff --git a/emu/bus.c b/emu/bus.c
new file mode 100644
index 0000000..5bbbcb1
--- /dev/null
+++ b/emu/bus.c
@@ -0,0 +1,75 @@
+#include "bus.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+static device_vtable_t const bus_vtable = {
+	bus_read,
+	bus_write,
+	bus_deinit
+};
+
+void bus_init( bus_t *bus )
+{
+	device_init( &bus->base, "bus" );
+	((device_t *)bus)->vtable = (device_vtable_t *)&bus_vtable;
+	
+	bus->nof_devices = 0;	
+}
+
+void bus_register( bus_t *bus, device_t *device, uint16_t from, uint16_t to )
+{
+	if( bus->nof_devices < MAX_NOF_DEVICES ) {
+		registered_device_t *reg = &bus->devices[bus->nof_devices];
+		reg->device = device;
+		reg->from = from;
+		reg->to = to;
+		bus->nof_devices++;
+	} else {
+		fprintf( stderr, "ERROR: too many devices on bus\n" );
+		exit( EXIT_FAILURE );
+	}
+}
+
+uint8_t bus_read( void *obj, uint16_t addr )
+{
+	bus_t *bus = (bus_t *)obj;
+
+	for( int i = 0; i < bus->nof_devices; i++ ) {
+		registered_device_t *reg = &bus->devices[i];
+		if( reg->from <= addr && addr <= reg->to ) {
+			return reg->device->vtable->read( reg->device, addr );
+		}
+	}
+
+	fprintf( stderr, "ERROR: illegal bus access reading from address %04X\n", addr );
+	
+	return 0;
+}
+
+void bus_write( void *obj, uint16_t addr, uint8_t data )
+{
+	bus_t *bus = (bus_t *)obj;
+
+	for( int i = 0; i < bus->nof_devices; i++ ) {
+		registered_device_t *reg = &bus->devices[i];
+		if( reg->from <= addr && addr <= reg->to ) {
+			return reg->device->vtable->write( reg->device, addr, data );
+		}
+	}
+
+	fprintf( stderr, "ERROR: illegal bus access writing from address %04X\n", addr );
+}
+
+void bus_deinit( void *obj )
+{
+	bus_t *bus = (bus_t *)obj;
+
+	for( int i = bus->nof_devices - 1; i >= 0; i-- ) {
+		registered_device_t *reg = &bus->devices[i];
+		reg->device->vtable->deinit( reg->device );
+	}
+	bus->nof_devices = 0;
+
+	device_deinit( &bus->base );
+}
diff --git a/emu/bus.h b/emu/bus.h
new file mode 100644
index 0000000..baa2fe2
--- /dev/null
+++ b/emu/bus.h
@@ -0,0 +1,28 @@
+#ifndef BUS_H
+#define BUS_H
+
+#include "device.h"
+
+enum {
+	MAX_NOF_DEVICES = 5
+};
+
+typedef struct registered_device_t {
+	device_t *device;
+	uint16_t from;
+	uint16_t to;
+} registered_device_t;
+
+typedef struct bus_t {
+	device_t base;
+	int nof_devices;
+	registered_device_t devices[MAX_NOF_DEVICES];
+} bus_t;
+
+void bus_init( bus_t *bus );
+void bus_register( bus_t *bus, device_t *device, uint16_t from, uint16_t to );
+uint8_t bus_read( void *obj, uint16_t addr );
+void bus_write( void *obj, uint16_t addr, uint8_t data );
+void bus_deinit( void *obj );
+
+#endif
diff --git a/emu/device.c b/emu/device.c
new file mode 100644
index 0000000..ecf3d2d
--- /dev/null
+++ b/emu/device.c
@@ -0,0 +1,44 @@
+#include "device.h"
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static device_vtable_t const device_vtable = {
+	device_read,
+	device_write,
+	device_deinit
+};
+
+void device_init( device_t *device, const char *name )
+{
+	device->name = strdup( name );
+
+	device->vtable = &device_vtable;
+}
+
+uint8_t device_read( void *obj, uint16_t addr )
+{
+	device_t *device = (device_t *)obj;
+	
+	fprintf( stderr, "WARN: read access on abstract device '%s' on address %04X\n",
+		device->name, addr );
+		
+	return 0;
+}
+
+void device_write( void *obj, uint16_t addr, uint8_t data )
+{
+	device_t *device = (device_t *)obj;
+
+	fprintf( stderr, "WARN: write access on abstract device '%s' on address %04X\n",
+		device->name, addr );	
+}
+
+void device_deinit( void *obj )
+{
+	device_t *device = (device_t *)obj;
+	
+	free( device->name );
+}
+
diff --git a/emu/device.h b/emu/device.h
new file mode 100644
index 0000000..ce2abad
--- /dev/null
+++ b/emu/device.h
@@ -0,0 +1,24 @@
+#ifndef DEVICE_H
+#define DEVICE_H
+
+#include <stdint.h>
+
+struct device_t;
+
+typedef struct device_vtable_t {
+	uint8_t (*read)( void *obj, uint16_t addr );
+	void (*write)( void *obj, uint16_t addr, uint8_t data );
+	void (*deinit)( void *obj );	
+} device_vtable_t;
+
+typedef struct device_t {
+	device_vtable_t const *vtable;
+	char *name;
+} device_t;
+
+void device_init( device_t *device, const char *name );
+uint8_t device_read( void *obj, uint16_t addr );
+void device_write( void *obj, uint16_t addr, uint8_t data );
+void device_deinit( void *obj );
+
+#endif
diff --git a/emu/emu.c b/emu/emu.c
index 2723880..95bc5cb 100644
--- a/emu/emu.c
+++ b/emu/emu.c
@@ -23,9 +23,11 @@ int main( int argc, char *argv[] )
 {
 	struct gengetopt_args_info args_info;
 	emul_t emul;
-	cpu_6502_t cpu;
-	memory_t memory;
+	bus_t bus;
+	memory_t rom;
+	memory_t ram;
 	seg7_t seg7;
+	cpu_6502_t cpu;
 
 	if( parse_options_and_arguments( argc, argv, &args_info ) != 0 ) {
 		exit( EXIT_FAILURE );
@@ -36,12 +38,19 @@ int main( int argc, char *argv[] )
 		exit( EXIT_SUCCESS );
 	}
 
-	seg7_init( &seg7 );
-		
-	memory_init( &memory, &seg7 );
-	memory_load( &memory, ROM_START, ROM_SIZE, args_info.rom_arg );
+	bus_init( &bus );
+			
+	memory_init( &rom, MEMORY_ROM, ROM_START, ROM_SIZE );
+	memory_load( &rom, args_info.rom_arg );
+	bus_register( &bus, &rom.base, ROM_START, ROM_END );
+	
+	memory_init( &ram, MEMORY_RAM, RAM_START, RAM_SIZE );
+	bus_register( &bus, &ram.base, RAM_START, RAM_END );
+
+	seg7_init( &seg7, VIA_START );
+	bus_register( &bus, &seg7.base, VIA_START, VIA_END );
 		
-	cpu_6502_init( &cpu, &memory );
+	cpu_6502_init( &cpu, &bus );
 	if( args_info.debug_given ) {
 		if( args_info.print_cpu_given ) {
 			cpu.debug_flags |= DEBUG_STATUS;
@@ -58,7 +67,7 @@ int main( int argc, char *argv[] )
 	}
 	cpu_6502_reset( &cpu );
 		
-	emul_init( &emul, &cpu, &memory, args_info.width_arg, args_info.height_arg );
+	emul_init( &emul, &cpu, &bus, args_info.width_arg, args_info.height_arg );
 	if( args_info.gui_given ) {
 		if( args_info.debug_given ) {
 			fprintf( stderr, "ERROR: don't run debug and GUI together! Uses too many resources!\n" );
@@ -70,6 +79,7 @@ int main( int argc, char *argv[] )
 	
 	emul_run( &emul, args_info.steps_arg );
 	
+	bus_deinit( &bus );
 	emul_free( &emul );
 	exit( EXIT_SUCCESS );
 }
diff --git a/emu/emul.c b/emu/emul.c
index 930f112..602ce33 100644
--- a/emu/emul.c
+++ b/emu/emul.c
@@ -3,10 +3,10 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-void emul_init( emul_t *emul, cpu_6502_t *cpu, memory_t *memory, int width, int height )
+void emul_init( emul_t *emul, cpu_6502_t *cpu, bus_t *bus, int width, int height )
 {
 	emul->cpu = cpu;
-	emul->memory = memory;
+	emul->bus = bus;
 	emul->gui = false;
 	emul->width = width;
 	emul->height = height;
diff --git a/emu/emul.h b/emu/emul.h
index 6012309..6945143 100644
--- a/emu/emul.h
+++ b/emu/emul.h
@@ -2,7 +2,7 @@
 #define EMUL_H
 
 #include "6502.h"
-#include "memory.h"
+#include "bus.h"
 
 #include <stdbool.h>
 
@@ -11,15 +11,25 @@
 #endif
 
 enum {
-	ROM_START = 0xF800,
-	ROM_SIZE = 2048,
+	ROM_START = 0xf800,
+	ROM_END   = 0xffff,
+	ROM_SIZE  = 2048,
+	
+	RAM_START = 0x0000,
+	RAM_END   = 0x01ff,
+	RAM_SIZE  = 512,
+	
+	VIA_START = 0x6000,
+	VIA_END   = 0x600f,
+	
 	CPU_FREQUENCY = 1000000,
+	
 	DISPLAY_FPS = 25
 };
 
 typedef struct emul_t {
 	cpu_6502_t *cpu;
-	memory_t *memory;
+	bus_t *bus;
 	bool gui;
 	int width;
 	int height;
@@ -31,7 +41,7 @@ typedef struct emul_t {
 #endif
 } emul_t;
 
-void emul_init( emul_t *emul, cpu_6502_t *cpu, memory_t *memory, int width, int height );
+void emul_init( emul_t *emul, cpu_6502_t *cpu, bus_t *bus, int width, int height );
 void emul_start( emul_t *emul );
 void emul_run( emul_t *emul, int nof_steps );
 void emul_free( emul_t *emul );
diff --git a/emu/memory.c b/emu/memory.c
index 408e621..52332e3 100644
--- a/emu/memory.c
+++ b/emu/memory.c
@@ -1,52 +1,63 @@
 #include "memory.h"
 
 #include <stdio.h>
+#include <stdlib.h>
 
-void memory_init( memory_t *memory, seg7_t *seg )
-{
-	memory->read = memory_read;
-	memory->write = memory_write;
-	memory->seg = seg;
-}
+static device_vtable_t const memory_vtable = {
+	memory_read,
+	memory_write,
+	memory_deinit
+};
 
-uint8_t memory_read( memory_t *memory, uint16_t addr )
+void memory_init( memory_t *memory, memory_type_t type, uint16_t addr, uint16_t size )
 {
-	if( addr <= 0x3FFF ) {
-		// RAM access
-		return memory->cell[addr];
-	} else if( addr <= 0x8000 ) {
-		return seg7_read( memory->seg, addr );
-	} else {
-		// ROM access
-		return memory->cell[addr];
-	}
-}
+	device_init( &memory->base, ( type == MEMORY_ROM ) ? "ROM" : "RAM" );
 
-void memory_write( memory_t *memory, uint16_t addr, uint8_t data )
-{
-	if( addr <= 0x3FFF ) {
-		// RAM access
-		memory->cell[addr] = data;
-	} else if( addr <= 0x8000 ) {
-		seg7_write( memory->seg, addr, data );
-	} else {
-		// ignore writes to ROM
-	}
+	memory->type = type;
+	memory->addr = addr;
+	memory->size = size;
+	memory->cell = malloc( memory->size );
+	memory->base.vtable = (device_vtable_t *)&memory_vtable;
 }
 
-void memory_load( memory_t *memory, uint16_t addr, uint16_t size, const char *filename )
+void memory_load( memory_t *memory, const char *filename )
 {
-	if( addr >= 0x8000 ) {
+	if( memory->type == MEMORY_ROM ) {
 		FILE *f = fopen( filename, "rb" );
 		if( f == NULL ) {
 			fprintf( stderr, "ERROR: Unable to open ROM file '%s'\n", filename );
 			exit( EXIT_FAILURE );
 		}
-		fread( &memory->cell[addr], size, 1, f );
+		fread( &memory->cell[0], memory->size, 1, f );
 		fclose( f );
 		fprintf( stderr, "INFO: Loaded firware from '%s' of size %d starting on address %04X\n",
-			filename, size, addr );
+			filename, memory->size, memory->addr );
 	} else {
-		fprintf( stderr, "ERROR: Cannot load firmware into RAM at address %04X\n", addr );
+		fprintf( stderr, "ERROR: Cannot load firmware into RAM at address %04X\n", memory->addr );
 	}
 }
+
+uint8_t memory_read( void *obj, uint16_t addr )
+{
+	memory_t *memory = (memory_t *)obj;
+	
+	return memory->cell[addr-memory->addr];
+}
+
+void memory_write( void *obj, uint16_t addr, uint8_t data )
+{
+	memory_t *memory = (memory_t *)obj;
+
+	if( memory->type && MEMORY_ROM ) {
+		// ignore writes to ROM
+	} else {
+		memory->cell[addr-memory->addr] = data;
+	}
+}
+
+void memory_deinit( void *obj )
+{
+	memory_t *memory = (memory_t *)obj;
+
+	device_deinit( &memory->base );
+}
diff --git a/emu/memory.h b/emu/memory.h
index b2abfee..a0d45b9 100644
--- a/emu/memory.h
+++ b/emu/memory.h
@@ -1,27 +1,30 @@
 #ifndef MEMORY_H
 #define MEMORY_H
 
-#include "7seg.h"
+#include "device.h"
 
 #include <stdint.h>
 
-enum {
-	MEMORY_SIZE = 65535
-};
+typedef enum memory_type_t {
+	MEMORY_ROM = 1,
+	MEMORY_RAM = 2
+} memory_type_t;
 
 typedef struct memory_t
 {
-	uint8_t cell[MEMORY_SIZE];
+	device_t base;
 	
-	seg7_t *seg;
-	
-	uint8_t (*read)( struct memory_t *memory, uint16_t addr );
-	void (*write)( struct memory_t *memory, uint16_t addr, uint8_t data );
+	memory_type_t type;
+	uint16_t addr;
+	int size;
+	uint8_t *cell;
 } memory_t;
 
-void memory_init( memory_t *memory, seg7_t *seg );
-uint8_t memory_read( memory_t *memory, uint16_t addr );
-void memory_write( memory_t *memory, uint16_t addr, uint8_t data );
-void memory_load( memory_t *memory, uint16_t addr, uint16_t size, const char *filename );
+void memory_init( memory_t *memory, memory_type_t type, uint16_t addr, uint16_t size );
+void memory_load( memory_t *memory, const char *filename );
+
+uint8_t memory_read( void *obj, uint16_t addr );
+void memory_write( void *obj, uint16_t addr, uint8_t data );
+void memory_deinit( void *obj );
 
 #endif