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refactor access to the sysram array

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This commit is contained in:
Raphael Jacquot 2019-02-09 00:55:09 +01:00
parent 229aab83fe
commit f8ef195563
2 changed files with 27 additions and 40 deletions
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5
hp48_01_io_ram.v
View file

@ -59,16 +59,13 @@ initial
`endif `endif
dp_ptr = 0; dp_ptr = 0;
`ifdef SIM `ifdef SIM
// initialization only for simulation
$display("io_ram: initializing to 0"); $display("io_ram: initializing to 0");
`endif
for (base_addr = 0; base_addr < IO_RAM_LEN; base_addr++) for (base_addr = 0; base_addr < IO_RAM_LEN; base_addr++)
begin begin
`ifdef SIM
$write("."); $write(".");
`endif
mmio_ram[base_addr] <= 0; mmio_ram[base_addr] <= 0;
end end
`ifdef SIM
$display("io_ram: setting base address to 0"); $display("io_ram: setting base address to 0");
`endif `endif
base_addr = 0; base_addr = 0;

62
hp48_02_sys_ram.v
View file

@ -25,16 +25,21 @@ module hp48_sys_ram (
output reg error output reg error
); );
`ifdef SIM
localparam SYS_RAM_LEN = 262144; localparam SYS_RAM_LEN = 262144;
`else
localparam SYS_RAM_LEN = 65536;
`endif
reg [0:0] addr_conf; reg [0:0] addr_conf;
reg [0:0] len_conf; reg [0:0] len_conf;
reg unsigned [19:0] base_addr; reg [19:0] base_addr;
reg unsigned [19:0] length; reg [19:0] length;
reg unsigned [19:0] pc_ptr; reg [19:0] last_addr;
reg unsigned [19:0] dp_ptr; reg [19:0] pc_ptr;
reg [3:0] sys_ram [0:SYS_RAM_LEN - 1]; reg [19:0] dp_ptr;
wire configured; reg [3:0] sys_ram [0:SYS_RAM_LEN - 1];
wire configured;
assign daisy_out = addr_conf & len_conf; assign daisy_out = addr_conf & len_conf;
assign configured = daisy_out; assign configured = daisy_out;
@ -55,13 +60,12 @@ initial
`endif `endif
error = 0; error = 0;
`ifdef SIM `ifdef SIM
// initialize only in simulation
$display("sys_ram: initializing to 0"); $display("sys_ram: initializing to 0");
`endif
for (base_addr = 0; base_addr < SYS_RAM_LEN; base_addr++) for (base_addr = 0; base_addr < SYS_RAM_LEN; base_addr++)
begin begin
sys_ram[base_addr] <= 0; sys_ram[base_addr] <= 0;
end end
`ifdef SIM
$display("sys_ram: setting pc and data pointers to 0"); $display("sys_ram: setting pc and data pointers to 0");
`endif `endif
pc_ptr = 0; pc_ptr = 0;
@ -85,9 +89,6 @@ initial
* *
*/ */
wire [19:0] last_addr;
assign last_addr = base_addr + length - 1;
// PC_PTR tests // PC_PTR tests
wire cmd_bus_pc; wire cmd_bus_pc;
@ -116,36 +117,24 @@ assign {dp_ptr_inf_l_addr, dp_ptr_minus_l_addr} = dp_ptr - last_addr - 1;
assign active_dp_ptr = cmd_bus_dp & b_addr_infeq_dp_ptr & dp_ptr_inf_l_addr; assign active_dp_ptr = cmd_bus_dp & b_addr_infeq_dp_ptr & dp_ptr_inf_l_addr;
// global // global
wire cmd_read;
wire cmd_write;
assign cmd_read = (command == `BUSCMD_PC_READ) | (command == `BUSCMD_DP_WRITE);
assign cmd_write = (command == `BUSCMD_DP_WRITE) | (command == `BUSCMD_PC_WRITE);
assign active = (active_pc_ptr | active_dp_ptr) & configured; assign active = (active_pc_ptr | active_dp_ptr) & configured;
always @(posedge strobe) begin always @(posedge strobe) begin
if (configured & cmd_read)
nibble_out <= sys_ram[(cmd_bus_dp?dp_ptr:pc_ptr) - base_addr];
if (configured & cmd_write)
sys_ram[(cmd_bus_dp?dp_ptr:pc_ptr) - base_addr] <= nibble_in;
case (command) case (command)
`BUSCMD_PC_READ: begin `BUSCMD_PC_READ, `BUSCMD_PC_WRITE: begin
if (configured) begin
nibble_out <= sys_ram[pc_ptr];
// $display("SYSRAM (%b - %5h %5h) - PC_READ %5h -> %h", configured, base_addr, length, pc_ptr, sys_ram[pc_ptr]);
end else begin
// $display("SYSRAM (%b - %5h %5h) - PC_READ %5h UNCONFIGURED", configured, base_addr, length, pc_ptr);
end
pc_ptr <= pc_ptr + 1; pc_ptr <= pc_ptr + 1;
end end
`BUSCMD_DP_READ: begin `BUSCMD_DP_READ, `BUSCMD_DP_WRITE: begin
if (configured) begin
nibble_out <= sys_ram[dp_ptr];
// $display("SYSRAM (%b - %5h) - DP_READ %5h -> %h", configured, base_addr, length, dp_ptr, sys_ram[dp_ptr]);
end else begin
// $display("SYSRAM (%b - %5h %5h) - DP_READ %5h UNCONFIGURED", configured, base_addr, length, dp_ptr);
end
dp_ptr <= dp_ptr + 1;
end
`BUSCMD_DP_WRITE: begin
if (configured) begin
sys_ram[dp_ptr] <= nibble_in;
// $display("SYSRAM (%b - %5h %5h) - DP_WRITE %5h -> %h", configured, base_addr, length, dp_ptr, nibble_in);
end else begin
// $display("SYSRAM (%b - %5h %5h) - DP_WRITE %5h -> %h UNCONFIGURED", configured, base_addr, length, dp_ptr, nibble_in);
end
dp_ptr <= dp_ptr + 1; dp_ptr <= dp_ptr + 1;
end end
`BUSCMD_LOAD_PC: begin `BUSCMD_LOAD_PC: begin
@ -167,6 +156,7 @@ always @(posedge strobe) begin
if (len_conf & !addr_conf) begin if (len_conf & !addr_conf) begin
base_addr <= address; base_addr <= address;
addr_conf <= 1; addr_conf <= 1;
last_addr <= address + length - 1;
$display("SYSRAM (%b - %5h %5h) - CONFIGURE ADDRESS %5h", configured, address, length, address); $display("SYSRAM (%b - %5h %5h) - CONFIGURE ADDRESS %5h", configured, address, length, address);
end end
end else begin end else begin