fixed relative memory addressing bug

3 files changed, 13 insertions, 12 deletions

diff --git a/src/memory_interface.v b/src/memory_interface.v
index da06d1a..e6ff713 100644
--- a/src/memory_interface.v
+++ b/src/memory_interface.v
@@ -11,19 +11,20 @@ module memory_interface (
 
 reg ram_we;
 wire [31:0] ram_read_data, rom_read_data;
+reg [31:0] rel_addr;
 
 ram #(.N(32), .SIZE(1024)) ram(
   .clk(clk),
   .rstn(rstn),
   .we(ram_we),
-  .addr(addr),
+  .addr(rel_addr),
   .data_read(ram_read_data),
   .data_write(wd)
 );
 
 rom #(.N(32), .SIZE(1024)) rom(
   .clk(clk),
-  .addr(addr),
+  .addr(rel_addr),
   .data_read(rom_read_data)
 );
 
@@ -42,18 +43,18 @@ rom #(.N(32), .SIZE(1024)) rom(
 
 
 always @(*) begin
-  if (addr[31:16] >= 16'h0001 && addr[31:16] <= 16'h000F) begin
+  if (         addr >= 32'h0001_0000 && addr <= 32'h000F_0000) begin
     ram_we = 0;
     rd = rom_read_data;
-  end else if (addr[31:16] >= 16'h0010 && addr[31:16] <= 16'hFF0F) begin
+    rel_addr = addr - 32'h0001_0000;
+  end else if (addr >= 32'h0010_0000 && addr <= 32'hFF0F_0000) begin
     ram_we = we;
     rd = ram_read_data;
-  end else if (addr[31:16] >= 16'hFF10 && addr[31:16] <= 16'hFFFF) begin
-    ram_we = 0;
-    rd = 0;
+    rel_addr = addr - 32'h0010_0000;
   end else begin
     ram_we = 0;
     rd = 0;
+    rel_addr = 0;
   end
 end
 
diff --git a/src/ram.v b/src/ram.v
index 91bb133..541096e 100644
--- a/src/ram.v
+++ b/src/ram.v
@@ -5,7 +5,7 @@ module ram #(
     input clk,
     input rstn,
     input we,
-    input [log2(SIZE/4)-1:0] addr,
+    input [N-1:0] addr,
     input [N-1:0] data_write,
     output reg [N-1:0] data_read
 );
@@ -13,7 +13,7 @@ module ram #(
 `include "include/log2.vh"
 
 //(* RAM_STYLE="BLOCK" *)
-reg [N-1:0] mem [SIZE-1:0];
+reg [N-1:0] mem [0:SIZE-1];
 
 always @(posedge clk) begin
   if (we) mem[addr >> 2] <= data_write; 
diff --git a/src/rom.v b/src/rom.v
index b317094..d93ef07 100644
--- a/src/rom.v
+++ b/src/rom.v
@@ -3,7 +3,7 @@ module rom #(
   parameter SIZE = 1024
 )(
     input clk,
-    input [log2(SIZE/4)-1:0] addr,
+    input [N-1:0] addr,
     output reg [N-1:0] data_read
 );
 
@@ -11,10 +11,10 @@ module rom #(
 
 
 //(* RAM_STYLE="BLOCK" *)
-reg [N-1:0] mem [SIZE-1:0];
+reg [N-1:0] mem [0:SIZE-1];
 
 initial begin
-  $readmemh("build/rom.hex", mem, 0, SIZE/4-1);
+  $readmemh("build/rom.hex", mem, 0, SIZE-1);
 end
 
 always @(negedge clk) begin