mirror of
https://github.com/sxpert/hp-saturn
synced 2025-01-20 10:26:31 +01:00
cleanup the simulated rom interface
This commit is contained in:
Raphael Jacquot
parent
1444baca19
commit
f660168393
3 changed files with 74 additions and 42 deletions
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@ -27,4 +27,5 @@ MODE="664", GROUP="dialout"
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this is for ujprog libusb access
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ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6015", \
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GROUP="dialout", MODE="666"
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GROUP="dialout", MODE="666"
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@ -66,24 +66,27 @@ input wire [0:0] i_cmd_config;
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input wire [3:0] i_nibble;
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output reg [3:0] o_nibble;
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/*
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* events
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*/
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/******************************************************************************
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*
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* clocking enables
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*
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****************************************************************************/
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wire en_bus_send;
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wire en_bus_recv;
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wire en_bus_ecmd;
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wire en_bus_send;
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assign en_bus_send = i_en_bus_send && !i_stalled;
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wire en_bus_recv;
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assign en_bus_recv = i_en_bus_recv && !i_stalled;
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wire en_bus_ecmd;
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assign en_bus_ecmd = i_en_bus_ecmd && !i_stalled;
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/*
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* states
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*/
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/******************************************************************************
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*
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* state machine events
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*
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****************************************************************************/
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wire [0:0] addr_s;
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assign addr_s = addr_cnt == 5;
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// declarations
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reg [0:0] cmd_pc_read_s;
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reg [0:0] dp_read_s;
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@ -92,6 +95,8 @@ reg [0:0] cmd_load_dp_s;
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reg [0:0] cmd_config_s;
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reg [0:0] cmd_reset_s;
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wire [0:0] addr_s;
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wire [0:0] do_cmd_pc_read;
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wire [0:0] do_display_stalled;
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@ -120,6 +125,10 @@ wire [0:0] cmd_reset_uc;
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wire [0:0] do_unstall;
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wire [0:0] do_cleanup;
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// assigns
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assign addr_s = addr_cnt == 5;
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assign do_cmd_load_dp = i_cmd_load_dp && !cmd_load_dp_s;
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assign do_dp_read_data = i_cmd_dp_read && cmd_load_dp_s && (addr_s || dp_read_s);
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@ -149,7 +158,7 @@ assign do_cmd_pc_read = !cmd_pc_read_s &&
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do_pc_read_after_config ||
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do_pc_read_after_reset);
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assign do_display_stalled = i_read_stall && !o_stalled_by_bus &&
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assign do_display_stalled = en_bus_recv && i_read_stall && !o_stalled_by_bus &&
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!(do_cmd_pc_read ||
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do_dp_read_data ||
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do_pc_read_after_dp_read ||
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@ -166,9 +175,12 @@ assign do_cleanup = do_cleanup_after_dp_read ||
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cmd_load_dp_dp_write_uc ||
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cmd_config_uc ||
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cmd_reset_uc;
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/*
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* test rom...
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*/
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/******************************************************************************
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*
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* test rom
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*
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****************************************************************************/
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`ifdef SIM
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`define ROMBITS 20
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`else
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@ -177,11 +189,30 @@ assign do_cleanup = do_cleanup_after_dp_read ||
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reg [3:0] rom [0:2**`ROMBITS-1];
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wire [0:0] last_cmd_pc_read;
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wire [0:0] last_cmd_dp_read;
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wire [0:0] do_read_from_bus;
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wire [0:0] use_pc_as_pointer;
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wire [`ROMBITS-1:0] read_pointer;
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assign last_cmd_pc_read = (last_cmd == `BUSCMD_PC_READ);
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assign last_cmd_dp_read = (last_cmd == `BUSCMD_DP_READ);
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assign do_read_from_bus = en_bus_recv && (!i_read_stall || do_dp_read_data) && (last_cmd_pc_read || last_cmd_dp_read);
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assign use_pc_as_pointer = last_cmd_pc_read ;
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assign read_pointer = use_pc_as_pointer?local_pc[`ROMBITS-1:0]:local_dp[`ROMBITS-1:0];
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/******************************************************************************
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*
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* the controller itself
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*
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****************************************************************************/
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initial begin
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`ifdef SIM
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$readmemh("rom-gx-r.hex", rom);
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// `ifdef SIM
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$readmemh("rom-gx-r.hex", rom, 0, 2**`ROMBITS-1);
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// $readmemh( "testrom-2.hex", rom);
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`ifdef SIM
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// $monitor({"o_stalled_by_bus %b | i_read_stall %b | i_cmd_dp_read %b |",
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// " cmd_load_dp_s %b | addr_s %b | dp_read_s %b |do_dp_read_data %b"},
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// o_stalled_by_bus, i_read_stall, i_cmd_dp_read, cmd_load_dp_s,
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@ -303,8 +334,10 @@ always @(posedge i_clk) begin
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// sending address bits
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if (send_addr) begin
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`ifdef SIM
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$display("BUS_SEND %0d: [%d] addr[%0d] %h =>",
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`PH_BUS_SEND, i_cycle_ctr, addr_cnt, i_address[addr_cnt*4+:4]);
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`endif
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o_bus_data <= i_address[addr_cnt*4+:4];
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addr_cnt <= addr_cnt + 1;
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o_bus_strobe <= 1;
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@ -336,38 +369,35 @@ always @(posedge i_clk) begin
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*
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*/
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if (en_bus_recv) begin
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if (!i_read_stall || do_dp_read_data)
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case (last_cmd)
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`BUSCMD_PC_READ: begin
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$display("BUS_RECV %0d: [%d] <= READ(PC) [%5h] %h", `PH_BUS_RECV, i_cycle_ctr, local_pc, rom[local_pc[`ROMBITS-1:0]]);
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o_nibble <= rom[local_pc[`ROMBITS-1:0]];
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local_pc <= local_pc + 1;
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end
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`BUSCMD_DP_READ: begin
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$display("BUS_RECV %0d: [%d] <= READ(DP) [%5h] %h", `PH_BUS_RECV, i_cycle_ctr, local_dp, rom[local_dp[`ROMBITS-1:0]]);
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o_nibble <= rom[local_dp[`ROMBITS-1:0]];
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local_dp <= local_dp + 1;
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dp_read_s <= 1;
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end
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endcase
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if (do_display_stalled) begin
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if (do_read_from_bus) begin
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`ifdef SIM
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$display("BUS_RECV %0d: [%d] <= READ(%s) [%5h] %h",
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`PH_BUS_RECV, i_cycle_ctr, use_pc_as_pointer?"PC":"DP",
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read_pointer, rom[read_pointer]);
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`endif
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o_nibble <= rom[read_pointer];
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if (use_pc_as_pointer) local_pc <= local_pc + 1;
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else begin
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local_dp <= local_dp + 1;
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dp_read_s <= 1;
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end
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end
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if (do_display_stalled) begin
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$display("BUS_RECV %0d: [%d] STALLED", `PH_BUS_RECV, i_cycle_ctr);
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end
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end
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/*
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*
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* resets the bus automatically
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*
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*/
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if (en_bus_recv) begin
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o_bus_strobe <= 0;
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o_bus_cmd_data <= 1;
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end
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if (en_bus_ecmd) begin
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// stalling and unstalling stuff
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@ -390,9 +420,10 @@ always @(posedge i_clk) begin
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// command automatic switchover
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case (last_cmd)
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`BUSCMD_NOP: begin end
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`BUSCMD_LOAD_PC,
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`BUSCMD_LOAD_DP:
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if (send_addr && (addr_cnt == 5)) begin
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if (send_addr && addr_s) begin
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// reset the addr count for next time
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$display("BUS_ECMD %0d: [%d] <= %s_READ mode",
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`PH_BUS_ECMD, i_cycle_ctr,
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@ -363,7 +363,7 @@ always @(posedge clk) begin
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clock_end <= 0;
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cycle_ctr <= ~0;
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max_cycle <= 420;
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max_cycle <= 450;
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mem_ctrl_stall <= 0;
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`ifndef SIM
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