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FDS fixes (MiSTer-devel#309)
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Implemented disk transfers with disk IRQ. Fixes games like
Super Lode Runner which use their own disk functions instead
of the FDS bios.

Some games expect to read a value like $42 instead of $02 from
$4032 due to the open bus bits.

(changes from upstream commit 8c8b952)
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@paulb-nl @theypsilon
paulb-nl authored and theypsilon committed Apr 17, 2022
2 parents b910b85 + 8c8b952 commit ad702f5
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Showing 6 changed files with 376 additions and 710 deletions.
56 changes: 15 additions & 41 deletions NES.sv
View file
Expand Up @@ -290,7 +290,7 @@ wire pal_video = |status[24:23];
wire hide_overscan = status[4] && ~pal_video;
wire [3:0] palette2_osd = status[49:47];
wire joy_swap = status[9] ^ (raw_serial || piano); // Controller on port 2 for Miracle Piano/SNAC
wire fds_swap_invert = status[16];
wire fds_auto_eject = ~status[16];
wire ext_audio = ~status[30];
wire int_audio = ~status[31];

Expand Down Expand Up @@ -546,15 +546,6 @@ wire [7:0] nes_joy_D = { joyD[0], joyD[1], joyD[2], joyD[3], joyD[7], joyD[6], j
wire mic_button = joyA[9] | joyB[9];
wire fds_btn = joyA[8] | joyB[8];

reg [22:0] clkcount;
always@(posedge clk) begin
if (nes_ce == 3) begin
clkcount<=clkcount+1'd1;
end
end

wire fds_eject = swap_delay[2] | fds_swap_invert ? fds_btn : (clkcount[22] | fds_btn);

reg [1:0] nes_ce;

wire raw_serial = status[26];
Expand Down Expand Up @@ -767,8 +758,7 @@ wire bram_en;
wire trigger;
wire light;

wire [1:0] diskside_req;
reg [1:0] diskside;
wire [1:0] diskside;
reg diskside_info;
always @(posedge clk) begin
reg [1:0] old_diskside;
Expand Down Expand Up @@ -829,10 +819,12 @@ NES nes (
.joypad_clock (joypad_clock),
.joypad1_data (joypad1_data),
.joypad2_data (joypad2_data),
.diskside_req (diskside_req),

.diskside (diskside),
.fds_busy (fds_busy),
.fds_eject (fds_eject),
.fds_eject (fds_btn),
.fds_auto_eject (fds_auto_eject),
.max_diskside (max_diskside),

// Memory transactions
.cpumem_addr (cpu_addr ),
Expand Down Expand Up @@ -908,17 +900,13 @@ always @(posedge clk) begin
end
end

dpram #("rtl/fdspatch.mif", 13) biospatch
spram #(.addr_width(13)) fds_bios
(
.clock_a(clk),
.address_a(ioctl_addr[12:0]),
.wren_a(bios_write),
.data_a(bios_data ^ loader_write_data),
.q_a(),

.clock_b(clk),
.address_b(loader_addr[12:0]),
.q_b(bios_data)
.clock(clk),
.address(loader_addr[12:0]),
.wren(bios_write),
.data(loader_write_data),
.q(bios_data)
);

wire [7:0] nsf_data;
Expand Down Expand Up @@ -1174,14 +1162,14 @@ end

reg bk_ena = 0;
reg old_downloading = 0;
reg [1:0] last_diskside = 2'd3;
reg [1:0] max_diskside = 2'd3;
always @(posedge clk) begin
old_downloading <= downloading;
if(~old_downloading & downloading) bk_ena <= 0;

//Save file always mounted in the end of downloading state.
if(downloading && img_mounted && !img_readonly) bk_ena <= 1;
if(~bk_ena && loader_write_triggered) last_diskside <= loader_addr_mem[17:16];
if(~bk_ena && loader_write_triggered) max_diskside <= loader_addr_mem[17:16];
end

wire bk_load = status[6];
Expand All @@ -1191,12 +1179,8 @@ reg bk_loading_req = 0;
reg bk_request = 0;
wire bk_busy = (bk_state == S_COPY);
reg fds_busy;
reg old_fds_btn;
reg [2:0] swap_delay;
reg [1:0] diskside_btn;

wire [8:0] save_sz = fds ? rom_sz[17:9] : bram_en ? 9'd3 : (prg_nvram == 4'd7) ? 9'd15 : 9'd63;
wire [1:0] diskside_req_use = fds_swap_invert ? diskside_btn : diskside_req;
wire [1:0] next_btn_diskside = (last_diskside == diskside_btn) ? 2'd0 : diskside_btn + 2'd1;

typedef enum bit [1:0] { S_IDLE, S_COPY } mystate;
mystate bk_state = S_IDLE;
Expand All @@ -1211,26 +1195,16 @@ always @(posedge clk) begin : save_block
old_save <= bk_save & bk_ena;
old_ack <= sd_ack;
fds_busy <= (bk_state != S_IDLE) || bk_request;
old_fds_btn <= fds_btn;

if(~old_ack & sd_ack) {sd_rd, sd_wr} <= 0;
if (swap_delay == {1'b1, clkcount[22:21]}) begin
swap_delay[2] <= 0;
end
if(~old_fds_btn & fds_btn & ~fds_busy & ~swap_delay[2]) diskside_btn <= next_btn_diskside;

if (downloading) begin
diskside <= 2'd0;
bk_state <= S_IDLE;
bk_request <= 0;
diskside_btn <= 2'd0;
end else if(bk_state == S_IDLE) begin
if((~old_load & bk_load) | (~old_save & bk_save)) begin
bk_loading <= bk_load;
bk_request <= 1;
end else if((diskside_req_use != diskside) && ~downloading && ~bk_request && fds) begin
diskside <= diskside_req_use;
swap_delay <= {1'b1, ~clkcount[22:21]};
end
if(old_downloading & ~downloading & |img_size & bk_ena) begin
bk_loading <= 1;
Expand Down
17 changes: 10 additions & 7 deletions rtl/cart.sv
View file
Expand Up @@ -55,10 +55,11 @@ module cart_top (
output reg irq,
input [15:0] audio_in,
output reg [15:0] audio, // External Audio
output reg [1:0] diskside_auto,
input [1:0] diskside,
output reg [1:0] diskside,
input fds_busy, // FDS Disk Swap Busy
input fds_eject, // FDS Disk Swap Pause
input fds_auto_eject,
input [1:0] max_diskside,
// savestates
input [63:0] SaveStateBus_Din,
input [ 9:0] SaveStateBus_Adr,
Expand Down Expand Up @@ -2106,7 +2107,7 @@ Mapper413 map413 (
// Notes : Uses a special wire to signal disk changes. Req. modified BIOS. //
// Games : Bio Miracle for audio, Various unlicensed games for compatibility. //
//*****************************************************************************//
tri0 [1:0] fds_diskside_auto;
tri0 [1:0] fds_diskside;
MapperFDS mapfds(
.clk (clk),
.ce (ce),
Expand All @@ -2130,11 +2131,13 @@ MapperFDS mapfds(
.audio_in (fds_audio),
.audio_b (audio_out_b),
// Special ports
.prg_dbus (prg_from_ram),
.audio_dout (fds_data),
.diskside_auto_b (fds_diskside_auto),
.diskside (diskside),
.diskside_b (fds_diskside),
.max_diskside (max_diskside),
.fds_busy (fds_busy),
.fds_eject (fds_eject)
.fds_eject_btn (fds_eject),
.fds_auto_eject_en (fds_auto_eject)
);

//*****************************************************************************//
Expand Down Expand Up @@ -2312,7 +2315,7 @@ always @* begin
// Currently only used for Mapper 413 Misc ROM. Expand if needed.
prg_aout[24:22] = me[413] ? prg_aoute_m413 : 3'd0;

{diskside_auto} = {fds_diskside_auto};
{diskside} = {fds_diskside};

// Behavior helper flags
{has_savestate, prg_conflict, prg_bus_write, has_chr_dout} = {flags_out_b[3], flags_out_b[2], flags_out_b[1], flags_out_b[0]};
Expand Down

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