mem size

1 files changed, 16 insertions, 1 deletions

diff --git a/rtl/src/rom.v b/rtl/src/rom.v
index 60ca6e1..6cb9a92 100644
--- a/rtl/src/rom.v
+++ b/rtl/src/rom.v
@@ -7,6 +7,7 @@ module rom #(
 )(
     input             clk,
     input      [31:0] addr,
+    input       [2:0] size,
     output reg [31:0] rd
 );
 
@@ -21,8 +22,22 @@ initial begin
   $readmemh(ROM_FILE, mem, 0, SIZE-1);
 end
 
+wire [31:0] rd_w;
+wire [15:0] rd_h;
+wire  [7:0] rd_b;
+assign rd_w =  mem[addr >> 2];
+assign rd_h = (mem[addr >> 2] >> (addr[1]  * 16)) & 32'hFFFF;
+assign rd_b = (mem[addr >> 2] >> (addr[1:0] * 8)) & 32'hFF; 
+
 always @ (negedge clk) begin
-    rd <= mem[addr >> 2];
+  case (size)
+    FUNCT3_LS_W:  rd <= rd_w;
+    FUNCT3_LS_H:  rd <= { {16{rd_h[15]}}, rd_h };
+    FUNCT3_LS_B:  rd <= { {24{rd_b[7]}}, rd_b };
+    FUNCT3_LS_HU: rd <= rd_b;
+    FUNCT3_LS_BU: rd <= rd_h;
+    default:      rd <= rd_w;
+  endcase
 end
 
 endmodule