C64: add disk write protect switch

cores/c64/rtl/c1541/c1541_sd.vhd

@@ -33,6 +33,7 @@ port(
 	
 	disk_num : in std_logic_vector(9 downto 0);
 	disk_change : in std_logic;
+	disk_readonly : in std_logic;
 
 	iec_atn_i  : in std_logic;
 	iec_data_i : in std_logic;
@@ -171,7 +172,7 @@ begin
     freq            => freq,     -- motor frequency
     sync_n          => sync_n,   -- reading SYNC bytes
     byte_n          => byte_n,   -- byte ready
-    wps_n           => '1',      -- write-protect sense (0 = protected)
+    wps_n           => not disk_readonly,      -- write-protect sense (0 = protected)
     tr00_sense_n    => '1',      -- track 0 sense (unused?)
     act             => act,      -- activity LED
 

cores/c64/rtl/mist/c64_mist.vhd

@@ -128,14 +128,14 @@ constant CONF_STR : string :=
 	"F,CRT,Load Cartridge;" &--3
 --	"F,TAP,Load File;"&--4
 --	"F,T64,Load File;"&--5
+	"OE,Disk Write,Enable,Disable;"&
 	"O2,Video standard,PAL,NTSC;"&
 	"O8A,Scandoubler Fx,None,HQ2x-320,HQ2x-160,CRT 25%,CRT 50%;"&
 	"OD,SID,6581,8580;"&
 	"O3,Joysticks,normal,swapped;"&
 	"O6,Audio filter,On,Off;"&
 --	"OB,BIOS,C64,C64GS;" &
-	"T5,Reset & Detach Cartridge;"&
-	"V0,v0.35.00";
+	"T5,Reset & Detach Cartridge;";
 
 -- convert string to std_logic_vector to be given to user_io
 function to_slv(s: string) return std_logic_vector is 
@@ -840,6 +840,8 @@ begin
 		reset_key => reset_key
 	);
 
+	disk_readonly <= status(14);
+
     c64_iec_data_i <= c1541_iec_data_o;
     c64_iec_clk_i <= c1541_iec_clk_o;
 
@@ -878,7 +880,7 @@ begin
 
 		disk_change => sd_change,
 		disk_num  => (others => '0'), -- always 0 on MiST, the image is selected by the OSD menu
-		--disk_readonly => disk_readonly,
+		disk_readonly => disk_readonly,
 
 		iec_atn_i  => c1541_iec_atn_i,
 		iec_data_i => c1541_iec_data_i,