Implement turbo/slow motion feature that overclocks or underclocks the entire system at the push of a button

8 files changed, 213 insertions, 48 deletions

diff --git a/blastem.c b/blastem.c
index 1b5e138..b57952e 100644
--- a/blastem.c
+++ b/blastem.c
@@ -33,6 +33,8 @@
 #define LINES_NTSC 262
 #define LINES_PAL 312
 
+#define MAX_SOUND_CYCLES 100000
+
 uint32_t mclks_per_frame = MCLKS_LINE*LINES_NTSC;
 
 uint16_t cart[CARTRIDGE_WORDS];
@@ -206,6 +208,13 @@ void sync_z80(z80_context * z_context, uint32_t mclks)
 void sync_sound(genesis_context * gen, uint32_t target)
 {
 	//printf("YM | Cycle: %d, bpos: %d, PSG | Cycle: %d, bpos: %d\n", gen->ym->current_cycle, gen->ym->buffer_pos, gen->psg->cycles, gen->psg->buffer_pos * 2);
+	while (target > gen->psg->cycles && target - gen->psg->cycles > MAX_SOUND_CYCLES) {
+		uint32_t cur_target = gen->psg->cycles + MAX_SOUND_CYCLES;
+		//printf("Running PSG to cycle %d\n", cur_target);
+		psg_run(gen->psg, cur_target);
+		//printf("Running YM-2612 to cycle %d\n", cur_target);
+		ym_run(gen->ym, cur_target);
+	}
 	psg_run(gen->psg, target);
 	ym_run(gen->ym, target);
 
@@ -1492,6 +1501,17 @@ m68k_context * debugger(m68k_context * context, uint32_t address)
 	return context;
 }
 
+void set_speed_percent(genesis_context * context, uint32_t percent)
+{
+	uint32_t old_clock = context->master_clock;
+	context->master_clock = ((uint64_t)context->normal_clock * (uint64_t)percent) / 100;
+	while (context->ym->current_cycle != context->psg->cycles) {
+		sync_sound(context, context->psg->cycles + MCLKS_PER_PSG);
+	}
+	ym_adjust_master_clock(context->ym, context->master_clock);
+	psg_adjust_master_clock(context->psg, context->master_clock);
+}
+
 #define ROM_END   0x1A4
 #define RAM_ID    0x1B0
 #define RAM_FLAGS 0x1B2
@@ -1868,23 +1888,23 @@ int main(int argc, char ** argv)
 		render_init(width, height, title, fps, fullscreen);
 	}
 	vdp_context v_context;
+	genesis_context gen;
+	memset(&gen, 0, sizeof(gen));
+	gen.master_clock = gen.normal_clock = fps == 60 ? MCLKS_NTSC : MCLKS_PAL;
 
 	init_vdp_context(&v_context);
 
 	ym2612_context y_context;
-	ym_init(&y_context, render_sample_rate(), fps == 60 ? MCLKS_NTSC : MCLKS_PAL, MCLKS_PER_YM, render_audio_buffer(), ym_log ? YM_OPT_WAVE_LOG : 0);
+	ym_init(&y_context, render_sample_rate(), gen.master_clock, MCLKS_PER_YM, render_audio_buffer(), ym_log ? YM_OPT_WAVE_LOG : 0);
 
 	psg_context p_context;
-	psg_init(&p_context, render_sample_rate(), fps == 60 ? MCLKS_NTSC : MCLKS_PAL, MCLKS_PER_PSG, render_audio_buffer());
+	psg_init(&p_context, render_sample_rate(), gen.master_clock, MCLKS_PER_PSG, render_audio_buffer());
 
 	z80_context z_context;
 	x86_z80_options z_opts;
 	init_x86_z80_opts(&z_opts);
 	init_z80_context(&z_context, &z_opts);
 
-	genesis_context gen;
-	memset(&gen, 0, sizeof(gen));
-
 	z_context.system = &gen;
 	z_context.mem_pointers[0] = z80_ram;
 	z_context.sync_cycle = z_context.target_cycle = mclks_per_frame/MCLKS_PER_Z80;
diff --git a/blastem.h b/blastem.h
index 68bccfd..0ec7c61 100644
--- a/blastem.h
+++ b/blastem.h
@@ -1,6 +1,6 @@
 /*
  Copyright 2013 Michael Pavone
- This file is part of BlastEm. 
+ This file is part of BlastEm.
  BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
 */
 #ifndef BLASTEM_H_
@@ -30,6 +30,8 @@ typedef struct {
 	uint8_t        *save_ram;
 	uint32_t       save_ram_mask;
 	uint32_t       save_flags;
+	uint32_t       master_clock; //Current master clock value
+	uint32_t       normal_clock; //Normal master clock (used to restore master clock after turbo mode)
 	uint8_t        bank_regs[8];
 	io_port        ports[3];
 } genesis_context;
@@ -43,6 +45,7 @@ extern uint8_t reset;
 
 uint16_t read_dma_value(uint32_t address);
 m68k_context * debugger(m68k_context * context, uint32_t address);
+void set_speed_percent(genesis_context * context, uint32_t percent);
 
 #endif //BLASTEM_H_
 
diff --git a/default.cfg b/default.cfg
index 1959d5c..ef8bace 100644
--- a/default.cfg
+++ b/default.cfg
@@ -19,6 +19,16 @@ bindings {
 		u ui.enter_debugger
 		esc ui.exit
 		` ui.save_state
+		0 ui.set_speed.0
+		1 ui.set_speed.1
+		2 ui.set_speed.2
+		3 ui.set_speed.3
+		4 ui.set_speed.4
+		5 ui.set_speed.5
+		6 ui.set_speed.6
+		7 ui.set_speed.7
+		= ui.next_speed
+		- ui.prev_speed
 	}
 	pads {
 		0 {
@@ -53,5 +63,17 @@ audio {
 	buffer 512
 }
 
+clocks {
+	speeds {
+		1 150
+		2 200
+		3 300
+		4 400
+		5 25
+		6 50
+		7 75
+	}
+}
+
 default_region U
 
diff --git a/io.c b/io.c
index b9e95c1..c83f756 100644
--- a/io.c
+++ b/io.c
@@ -1,6 +1,6 @@
 /*
  Copyright 2013 Michael Pavone
- This file is part of BlastEm. 
+ This file is part of BlastEm.
  BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
 */
 #include "io.h"
@@ -18,7 +18,10 @@ typedef enum {
 	UI_DEBUG_MODE_INC,
 	UI_DEBUG_PAL_INC,
 	UI_ENTER_DEBUGGER,
-  UI_SAVE_STATE,
+	UI_SAVE_STATE,
+	UI_SET_SPEED,
+	UI_NEXT_SPEED,
+	UI_PREV_SPEED,
 	UI_EXIT
 } ui_action;
 
@@ -139,9 +142,9 @@ void bind_dpad_gamepad(int joystick, int dpad, uint8_t direction, int gamepadnum
 	bind_dpad(joystick, dpad, direction, bind_type, button >> 12, button >> 8 & 0xF, button & 0xFF);
 }
 
-void bind_ui(int keycode, ui_action action)
+void bind_ui(int keycode, ui_action action, uint8_t param)
 {
-	bind_key(keycode, BIND_UI, action, 0, 0);
+	bind_key(keycode, BIND_UI, action, 0, param);
 }
 
 void handle_binding_down(keybinding * binding)
@@ -183,6 +186,10 @@ void handle_joydown(int joystick, int button)
 uint8_t ui_debug_mode = 0;
 uint8_t ui_debug_pal = 0;
 
+int current_speed = 0;
+int num_speeds = 1;
+uint32_t * speeds = NULL;
+
 void handle_binding_up(keybinding * binding)
 {
 	switch(binding->bind_type)
@@ -219,6 +226,32 @@ void handle_binding_up(keybinding * binding)
 		case UI_SAVE_STATE:
 			save_state = 1;
 			break;
+		case UI_NEXT_SPEED:
+			current_speed++;
+			if (current_speed >= num_speeds) {
+				current_speed = 0;
+			}
+			printf("Setting speed to %d: %d\n", current_speed, speeds[current_speed]);
+			set_speed_percent(genesis, speeds[current_speed]);
+			break;
+		case UI_PREV_SPEED:
+			current_speed--;
+			if (current_speed < 0) {
+				current_speed = num_speeds - 1;
+			}
+			printf("Setting speed to %d: %d\n", current_speed, speeds[current_speed]);
+			set_speed_percent(genesis, speeds[current_speed]);
+			break;
+		case UI_SET_SPEED:
+			if (binding->value < num_speeds) {
+				current_speed = binding->value;
+				printf("Setting speed to %d: %d\n", current_speed, speeds[current_speed]);
+				set_speed_percent(genesis, speeds[current_speed]);
+			} else {
+				printf("Setting speed to %d\n", speeds[current_speed]);
+				set_speed_percent(genesis, binding->value);
+			}
+			break;
 		case UI_EXIT:
 			exit(0);
 		}
@@ -286,6 +319,7 @@ int parse_binding_target(char * target, tern_node * padbuttons, int * ui_out, in
 			fprintf(stderr, "Gamepad mapping string '%s' refers to an invalid gamepad number %c\n", target, target[gpadslen]);
 		}
 	} else if(!memcmp(target, "ui.", strlen("ui."))) {
+		*padbutton_out = 0;
 		if (!strcmp(target + 3, "vdp_debug_mode")) {
 			*ui_out = UI_DEBUG_MODE_INC;
 		} else if(!strcmp(target + 3, "vdp_debug_pal")) {
@@ -294,6 +328,13 @@ int parse_binding_target(char * target, tern_node * padbuttons, int * ui_out, in
 			*ui_out = UI_ENTER_DEBUGGER;
 		} else if(!strcmp(target + 3, "save_state")) {
 			*ui_out = UI_SAVE_STATE;
+		} else if(!memcmp(target + 3, "set_speed.", strlen("set_speed."))) {
+			*ui_out = UI_SET_SPEED;
+			*padbutton_out = atoi(target + 3 + strlen("set_speed."));
+		} else if(!strcmp(target + 3, "next_speed")) {
+			*ui_out = UI_NEXT_SPEED;
+		} else if(!strcmp(target + 3, "prev_speed")) {
+			*ui_out = UI_PREV_SPEED;
 		} else if(!strcmp(target + 3, "exit")) {
 			*ui_out = UI_EXIT;
 		} else {
@@ -309,7 +350,7 @@ int parse_binding_target(char * target, tern_node * padbuttons, int * ui_out, in
 
 void process_keys(tern_node * cur, tern_node * special, tern_node * padbuttons, char * prefix)
 {
-	char * curstr;
+	char * curstr = NULL;
 	int len;
 	if (!cur) {
 		return;
@@ -324,8 +365,8 @@ void process_keys(tern_node * cur, tern_node * special, tern_node * padbuttons,
 		len = 0;
 	}
 	curstr[len] = cur->el;
+	curstr[len+1] = 0;
 	if (cur->el) {
-		curstr[len+1] = 0;
 		process_keys(cur->straight.next, special, padbuttons, curstr);
 	} else {
 		int keycode = tern_find_int(special, curstr, 0);
@@ -341,11 +382,59 @@ void process_keys(tern_node * cur, tern_node * special, tern_node * padbuttons,
 		if (bindtype == 1) {
 			bind_gamepad(keycode, padnum, button);
 		} else if(bindtype == 2) {
-			bind_ui(keycode, ui_func);
+			bind_ui(keycode, ui_func, button);
 		}
 	}
 	process_keys(cur->left, special, padbuttons, prefix);
 	process_keys(cur->right, special, padbuttons, prefix);
+	if (curstr && len) {
+		free(curstr);
+	}
+}
+
+void process_speeds(tern_node * cur, char * prefix)
+{
+	char * curstr = NULL;
+	int len;
+	if (!cur) {
+		return;
+	}
+	char onec[2];
+	if (prefix) {
+		len = strlen(prefix);
+		curstr = malloc(len + 2);
+		memcpy(curstr, prefix, len);
+	} else {
+		curstr = onec;
+		len = 0;
+	}
+	curstr[len] = cur->el;
+	curstr[len+1] = 0;
+	if (cur->el) {
+		process_speeds(cur->straight.next, curstr);
+	} else {
+		int speed_index = atoi(curstr);
+		if (speed_index < 1) {
+			if (!strcmp(curstr, "0")) {
+				fputs("Speed index 0 cannot be set to a custom value\n", stderr);
+			} else {
+				fprintf(stderr, "%s is not a valid speed index", curstr);
+			}
+		} else {
+			if (speed_index >= num_speeds) {
+				speeds = realloc(speeds, sizeof(uint32_t) * (speed_index+1));
+				for(; num_speeds < speed_index + 1; num_speeds++) {
+					speeds[num_speeds] = 0;
+				}
+			}
+			speeds[speed_index] = atoi(cur->straight.value.ptrval);
+		}
+	}
+	process_speeds(cur->left, prefix);
+	process_speeds(cur->right, prefix);
+	if (curstr && len) {
+		free(curstr);
+	}
 }
 
 void set_keybindings()
@@ -425,6 +514,16 @@ void set_keybindings()
 			}
 		}
 	}
+	tern_node * speed_nodes = tern_find_prefix(config, "clocksspeeds");
+	speeds = malloc(sizeof(uint32_t));
+	speeds[0] = 100;
+	process_speeds(speed_nodes, NULL);
+	for (int i = 0; i < num_speeds; i++) {
+		if (!speeds[i]) {
+			fprintf(stderr, "Speed index %d was not set to a valid percentage!", i);
+			speeds[i] = 100;
+		}
+	}
 }
 
 #define TH 0x40
diff --git a/psg.c b/psg.c
index 036a693..6ea47f9 100644
--- a/psg.c
+++ b/psg.c
@@ -1,6 +1,6 @@
 /*
  Copyright 2013 Michael Pavone
- This file is part of BlastEm. 
+ This file is part of BlastEm.
  BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
 */
 #include "psg.h"
@@ -13,15 +13,23 @@ void psg_init(psg_context * context, uint32_t sample_rate, uint32_t master_clock
 	memset(context, 0, sizeof(*context));
 	context->audio_buffer = malloc(sizeof(*context->audio_buffer) * samples_frame);
 	context->back_buffer = malloc(sizeof(*context->audio_buffer) * samples_frame);
-	double clock_rate = (double)master_clock / (double)clock_div;
-	context->buffer_inc = ((double)sample_rate / (double)master_clock) * clock_div;
 	context->clock_inc = clock_div;
+	context->sample_rate = sample_rate;
 	context->samples_frame = samples_frame;
+	psg_adjust_master_clock(context, master_clock);
 	for (int i = 0; i < 4; i++) {
 		context->volume[i] = 0xF;
 	}
 }
 
+#define BUFFER_INC_RES 1000000000UL
+
+void psg_adjust_master_clock(psg_context * context, uint32_t master_clock)
+{
+	uint64_t old_inc = context->buffer_inc;
+	context->buffer_inc = ((BUFFER_INC_RES * (uint64_t)context->sample_rate) / (uint64_t)master_clock) * (uint64_t)context->clock_inc;
+}
+
 void psg_write(psg_context * context, uint8_t value)
 {
 	if (value & 0x80) {
@@ -70,7 +78,7 @@ void psg_write(psg_context * context, uint8_t value)
 //table shamelessly swiped from PSG doc from smspower.org
 int16_t volume_table[16] = {
 	32767/PSG_VOL_DIV, 26028/PSG_VOL_DIV, 20675/PSG_VOL_DIV, 16422/PSG_VOL_DIV, 13045/PSG_VOL_DIV, 10362/PSG_VOL_DIV,
-	8231/PSG_VOL_DIV, 6568/PSG_VOL_DIV, 5193/PSG_VOL_DIV, 4125/PSG_VOL_DIV, 3277/PSG_VOL_DIV, 2603/PSG_VOL_DIV, 
+	8231/PSG_VOL_DIV, 6568/PSG_VOL_DIV, 5193/PSG_VOL_DIV, 4125/PSG_VOL_DIV, 3277/PSG_VOL_DIV, 2603/PSG_VOL_DIV,
 	2067/PSG_VOL_DIV, 1642/PSG_VOL_DIV, 1304/PSG_VOL_DIV, 0
 };
 
@@ -97,8 +105,8 @@ void psg_run(psg_context * context, uint32_t cycles)
 			}
 		}
 		context->buffer_fraction += context->buffer_inc;
-		if (context->buffer_fraction >= 1.0) {
-			context->buffer_fraction -= 1.0;
+		if (context->buffer_fraction >= BUFFER_INC_RES) {
+			context->buffer_fraction -= BUFFER_INC_RES;
 			int16_t acc = 0;
 			for (int i = 0; i < 3; i++) {
 				if (context->output_state[i]) {
diff --git a/psg.h b/psg.h
index 503bac2..4cd4552 100644
--- a/psg.h
+++ b/psg.h
@@ -1,6 +1,6 @@
 /*
  Copyright 2013 Michael Pavone
- This file is part of BlastEm. 
+ This file is part of BlastEm.
  BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
 */
 #ifndef PSG_CONTEXT_H_
@@ -11,11 +11,12 @@
 typedef struct {
 	int16_t  *audio_buffer;
 	int16_t  *back_buffer;
-	double   buffer_fraction;
-	double   buffer_inc;
+	uint64_t buffer_fraction;
+	uint64_t buffer_inc;
 	uint32_t buffer_pos;
 	uint32_t clock_inc;
 	uint32_t cycles;
+	uint32_t sample_rate;
 	uint32_t samples_frame;
 	uint16_t lsfr;
 	uint16_t counter_load[4];
@@ -30,6 +31,7 @@ typedef struct {
 
 
 void psg_init(psg_context * context, uint32_t sample_rate, uint32_t master_clock, uint32_t clock_div, uint32_t samples_frame);
+void psg_adjust_master_clock(psg_context * context, uint32_t master_clock);
 void psg_write(psg_context * context, uint8_t value);
 void psg_run(psg_context * context, uint32_t cycles);
 
diff --git a/ym2612.c b/ym2612.c
index a1ab1a0..2f7862d 100644
--- a/ym2612.c
+++ b/ym2612.c
@@ -1,6 +1,6 @@
 /*
  Copyright 2013 Michael Pavone
- This file is part of BlastEm. 
+ This file is part of BlastEm.
  BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
 */
 #include <string.h>
@@ -127,6 +127,13 @@ void ym_finalize_log()
 		}
 	}
 }
+#define BUFFER_INC_RES 1000000000UL
+
+void ym_adjust_master_clock(ym2612_context * context, uint32_t master_clock)
+{
+	uint64_t old_inc = context->buffer_inc;
+	context->buffer_inc = ((BUFFER_INC_RES * (uint64_t)context->sample_rate) / (uint64_t)master_clock) * (uint64_t)context->clock_inc;
+}
 
 void ym_init(ym2612_context * context, uint32_t sample_rate, uint32_t master_clock, uint32_t clock_div, uint32_t sample_limit, uint32_t options)
 {
@@ -134,8 +141,10 @@ void ym_init(ym2612_context * context, uint32_t sample_rate, uint32_t master_clo
 	memset(context, 0, sizeof(*context));
 	context->audio_buffer = malloc(sizeof(*context->audio_buffer) * sample_limit*2);
 	context->back_buffer = malloc(sizeof(*context->audio_buffer) * sample_limit*2);
-	context->buffer_inc = ((double)sample_rate / (double)master_clock) * clock_div * 6;
+	context->sample_rate = sample_rate;
 	context->clock_inc = clock_div * 6;
+	ym_adjust_master_clock(context, master_clock);
+
 	context->sample_limit = sample_limit*2;
 	context->write_cycle = CYCLE_NEVER;
 	for (int i = 0; i < NUM_OPERATORS; i++) {
@@ -451,29 +460,29 @@ void ym_run(ym2612_context * context, uint32_t to_cycle)
 		context->buffer_fraction += context->buffer_inc;
 		if (context->current_op == NUM_OPERATORS) {
 			context->current_op = 0;
-			if (context->buffer_fraction > 1.0) {
-				context->buffer_fraction -= 1.0;
-				context->audio_buffer[context->buffer_pos] = 0;
-				context->audio_buffer[context->buffer_pos + 1] = 0;
-				for (int i = 0; i < NUM_CHANNELS; i++) {
-					int16_t value = context->channels[i].output & 0x3FE0;
-					if (value & 0x2000) {
-						value |= 0xC000;
-					}
-					if (context->channels[i].logfile) {
-						fwrite(&value, sizeof(value), 1, context->channels[i].logfile);
-					}
-					if (context->channels[i].lr & 0x80) {
-						context->audio_buffer[context->buffer_pos] += value / YM_VOLUME_DIVIDER;
-					}
-					if (context->channels[i].lr & 0x40) {
-						context->audio_buffer[context->buffer_pos+1] += value / YM_VOLUME_DIVIDER;
-					}
+		}
+		if (context->buffer_fraction > BUFFER_INC_RES) {
+			context->buffer_fraction -= BUFFER_INC_RES;
+			context->audio_buffer[context->buffer_pos] = 0;
+			context->audio_buffer[context->buffer_pos + 1] = 0;
+			for (int i = 0; i < NUM_CHANNELS; i++) {
+				int16_t value = context->channels[i].output & 0x3FE0;
+				if (value & 0x2000) {
+					value |= 0xC000;
 				}
-				context->buffer_pos += 2;
-				if (context->buffer_pos == context->sample_limit) {
-					render_wait_ym(context);
+				if (context->channels[i].logfile) {
+					fwrite(&value, sizeof(value), 1, context->channels[i].logfile);
 				}
+				if (context->channels[i].lr & 0x80) {
+					context->audio_buffer[context->buffer_pos] += value / YM_VOLUME_DIVIDER;
+				}
+				if (context->channels[i].lr & 0x40) {
+					context->audio_buffer[context->buffer_pos+1] += value / YM_VOLUME_DIVIDER;
+				}
+			}
+			context->buffer_pos += 2;
+			if (context->buffer_pos == context->sample_limit) {
+				render_wait_ym(context);
 			}
 		}
 	}
diff --git a/ym2612.h b/ym2612.h
index 8516492..16a8cdf 100644
--- a/ym2612.h
+++ b/ym2612.h
@@ -1,6 +1,6 @@
 /*
  Copyright 2013 Michael Pavone
- This file is part of BlastEm. 
+ This file is part of BlastEm.
  BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
 */
 #ifndef YM2612_H_
@@ -59,10 +59,11 @@ typedef struct {
 typedef struct {
     int16_t     *audio_buffer;
     int16_t     *back_buffer;
-    double      buffer_fraction;
-    double      buffer_inc;
+    uint64_t    buffer_fraction;
+    uint64_t    buffer_inc;
     uint32_t    clock_inc;
     uint32_t    buffer_pos;
+	uint32_t    sample_rate;
     uint32_t    sample_limit;
 	uint32_t    current_cycle;
 	uint32_t    write_cycle;
@@ -93,6 +94,7 @@ typedef struct {
 } ym2612_context;
 
 void ym_init(ym2612_context * context, uint32_t sample_rate, uint32_t master_clock, uint32_t clock_div, uint32_t sample_limit, uint32_t options);
+void ym_adjust_master_clock(ym2612_context * context, uint32_t master_clock);
 void ym_run(ym2612_context * context, uint32_t to_cycle);
 void ym_address_write_part1(ym2612_context * context, uint8_t address);
 void ym_address_write_part2(ym2612_context * context, uint8_t address);