add fastforward and OSD-Pause feature

Gameboy.sv

@@ -151,7 +151,7 @@ assign AUDIO_MIX = status[8:7];
 // 0         1         2         3 
 // 01234567890123456789012345678901
 // 0123456789ABCDEFGHIJKLMNOPQRSTUV
-// XXXXXXXXXXXXXXXXXXXXX  XX
+// XXXXXXXXXXXXXXXXXXXXX  XXXXX
 
 `include "build_id.v" 
 localparam CONF_STR = {
@@ -179,9 +179,12 @@ localparam CONF_STR = {
 	"-;",
 	"OB,Boot,Normal,Fast;",
 	"O6,Link Port,Disabled,Enabled;",
+	"-;",
+	"OPQ,FastForward Sound,Normal,Hack,Off;",
+   "OR,Pause when OSD is open,Off,On;",
 	"-;",
 	"R0,Reset;",
-	"J1,A,B,Select,Start;",
+	"J1,A,B,Select,Start,FastForward;",
 	"V,v",`BUILD_DATE
 };
 
@@ -555,6 +558,9 @@ always @(posedge clk_sys) if(reset) begin
 	else if(cart_download) isGBC <= !filetype[7:4];
 end
 
+wire [15:0] GB_AUDIO_L;
+wire [15:0] GB_AUDIO_R;
+
 // the gameboy itself
 gb gb (
 	.reset	    ( reset      ),
@@ -562,6 +568,7 @@ gb gb (
 	.clk_sys     ( clk_sys    ),
 	.ce          ( ce_cpu     ),   // the whole gameboy runs on 4mhnz
 	.ce_2x       ( ce_cpu2x   ),   // ~8MHz in dualspeed mode (GBC)
+	.ce_sound    ( ce_sound   ),   // ~8Mhz if not fastforward
 	
 	.fast_boot   ( status[11]  ),
 
@@ -583,8 +590,8 @@ gb gb (
 	.gbc_bios_do     ( bios_do    ),
 
 	// audio
-	.audio_l 	 ( AUDIO_L	  ),
-	.audio_r 	 ( AUDIO_R	  ),
+	.audio_l 	 ( GB_AUDIO_L ),
+	.audio_r 	 ( GB_AUDIO_R ),
 	
 	// interface to the lcd
 	.lcd_clkena  ( lcd_clkena ),
@@ -609,6 +616,9 @@ gb gb (
 	.gg_available(gg_available)
 );
 
+assign AUDIO_L = (joystick_0[8] && status[26]) ? 16'd0 : GB_AUDIO_L;
+assign AUDIO_R = (joystick_0[8] && status[26]) ? 16'd0 : GB_AUDIO_R;
+
 // the lcd to vga converter
 wire [7:0] video_r, video_g, video_b;
 wire video_hs, video_vs;
@@ -739,14 +749,22 @@ video_mixer #(.LINE_LENGTH(200), .GAMMA(1)) video_mixer
 
 //////////////////////////////// CE ////////////////////////////////////
 
-reg ce_cpu, ce_cpu2x;
-always @(negedge clk_sys) begin
-	reg [2:0] div = 0;
 
-	div      <= div + 1'd1;
-	ce_cpu2x <= !div[1:0];
-	ce_cpu   <= !div[2:0];
-end
+wire ce_cpu, ce_cpu2x, ce_sound, ce_soundhack;
+wire cart_act = cart_wr | cart_rd;
+
+speedcontrol speedcontrol
+(
+	.clk_sys     (clk_sys),
+   .pause       (status[27] && OSD_STATUS && !ioctl_download),
+	.speedup     (joystick_0[8] && !ioctl_download && !OSD_STATUS),
+	.cart_act    (cart_act),
+	.ce          (ce_cpu),
+	.ce_2x       (ce_cpu2x),
+   .ce_2xNormal (ce_soundhack)
+);
+
+assign ce_sound = status[25] ? ce_soundhack : ce_cpu2x;
 
 ///////////////////////////// GBC BIOS /////////////////////////////////
 

files.qip

@@ -9,6 +9,7 @@ set_global_assignment -name VERILOG_FILE rtl/timer.v
 set_global_assignment -name VERILOG_FILE rtl/sprites.v
 set_global_assignment -name VERILOG_FILE rtl/lcd.v
 set_global_assignment -name VHDL_FILE rtl/gbc_snd.vhd
+set_global_assignment -name VHDL_FILE rtl/speedcontrol.vhd
 set_global_assignment -name VERILOG_FILE rtl/gb.v
 set_global_assignment -name VERILOG_FILE rtl/hdma.v
 set_global_assignment -name VERILOG_FILE rtl/link.v

rtl/gb.v

@@ -25,6 +25,7 @@ module gb (
 	input clk_sys,
 	input ce,
 	input ce_2x,
+	input ce_sound,
 
 	input fast_boot,
 	input [7:0] joystick,
@@ -267,7 +268,7 @@ wire audio_wr = !cpu_wr_n && sel_audio;
 
 gbc_snd audio (
 	.clk				( clk_sys			),
-	.ce            ( ce_2x           ),
+	.ce            ( ce_sound        ),
 	.reset			( reset_r			),
 	
 	.is_gbc        ( isGBC           ),

rtl/speedcontrol.vhd

@@ -0,0 +1,73 @@
+library IEEE;
+use IEEE.std_logic_1164.all;
+use IEEE.numeric_std.all;
+
+entity speedcontrol is
+   port
+   (
+      clk_sys     : in  std_logic;
+      pause       : in  std_logic;
+      speedup     : in  std_logic;
+      cart_act    : in  std_logic;
+      ce          : out std_logic := '0';
+      ce_2x       : out std_logic := '0';
+      ceNormal    : out std_logic := '0';
+      ce_2xNormal : out std_logic := '0'
+   );
+end entity;
+
+architecture arch of speedcontrol is
+
+   signal clkdiv       : unsigned(2 downto 0) := (others => '0');
+   signal nextdiv      : unsigned(2 downto 0) := (others => '0');
+                       
+   signal clkdivNormal : unsigned(2 downto 0) := (others => '0');
+                       
+   signal cart_act_1   : std_logic := '0';
+
+begin
+
+   process(clk_sys)
+   begin
+      if falling_edge(clk_sys) then
+         if (pause = '1') then
+         
+            ce          <= '0';
+            ce_2x       <= '0';
+            ceNormal    <= '0';
+            ce_2xNormal <= '0';
+            
+         else
+         
+            clkdiv       <= clkdiv + 1;
+            clkdivNormal <= clkdivNormal + 1;
+            
+            -- generation for speed depending on speedup
+            cart_act_1 <= cart_act;
+            
+            if (clkdiv = "000") then ce <= '1'; else ce <= '0'; end if;
+            if ((nextdiv = "111" and clkdiv(1 downto 0) = "00") or nextdiv = "001") then ce_2x <= '1'; else ce_2x <= '0'; end if;
+            
+            if (clkdiv = nextdiv and (clkdiv = "111" or cart_act = '0')) then
+               clkdiv  <= "000";
+               if (speedup = '1') then
+                  nextdiv <= "001";
+               else
+                  nextdiv <= "111";
+               end if;
+            end if;
+            
+            if (cart_act = '1' and cart_act_1 = '0') then
+               nextdiv <= "111";
+            end if;
+            
+            -- generation for non speed up base, used e.g. for sound hack
+            if (clkdivNormal = "000")            then ceNormal    <= '1'; else ceNormal    <= '0'; end if;
+            if (clkdivNormal(1 downto 0) = "00") then ce_2xNormal <= '1'; else ce_2xNormal <= '0'; end if;
+         
+         end if;
+         
+      end if;
+   end process;
+
+end architecture;