Clean up register read debug output

Right now we continually print all 3 possible GPRs an instruction
may be using. Add signals so we only print GPRs when they are
actually read. This should hopefully optimise away when synthesized.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>

diff --git a/common.vhdl b/common.vhdl
index 7455bf34ab25e3a16716a9409d8f549bd9152f8f..05e61596900c2fb57cf6af2b629e54fdc2bc174c 100644 (file)
--- a/common.vhdl
+++ b/common.vhdl
@@ -67,8 +67,11 @@ package common is
        constant Decode2ToMultiplyInit : Decode2ToMultiplyType := (valid => '0', insn_type => OP_ILLEGAL, rc => '0', others => (others => '0'));
 
        type Decode2ToRegisterFileType is record
+               read1_enable : std_ulogic;
                read1_reg : std_ulogic_vector(4 downto 0);
+               read2_enable : std_ulogic;
                read2_reg : std_ulogic_vector(4 downto 0);
+               read3_enable : std_ulogic;
                read3_reg : std_ulogic_vector(4 downto 0);
        end record;
 

diff --git a/decode2.vhdl b/decode2.vhdl
index bb25230aa6eaf95dc9960a95ad11b1855e9ee4ed..e92d064de826132b443d30891f6ee31401927583 100644 (file)
--- a/decode2.vhdl
+++ b/decode2.vhdl
@@ -206,6 +206,10 @@ begin
                decoded_reg_b := decode_input_reg_b (d.decode.input_reg_b, d.insn, r_in.read2_data);
                decoded_reg_c := decode_input_reg_c (d.decode.input_reg_c, d.insn, r_in.read3_data);
 
+               r_out.read1_enable <= decoded_reg_a.reg_valid;
+               r_out.read2_enable <= decoded_reg_b.reg_valid;
+               r_out.read3_enable <= decoded_reg_c.reg_valid;
+
                case d.decode.unit is
                when ALU =>
                        e_out.valid <= d.valid;

diff --git a/register_file.vhdl b/register_file.vhdl
index aa2ae9fea5347559d2ae3b79e721aafb6e5ae09a..7a6b513d4dd63bde48245ac162fb4a41b18cdae1 100644 (file)
--- a/register_file.vhdl
+++ b/register_file.vhdl
@@ -28,12 +28,12 @@ begin
                if rising_edge(clk) then
                        if w_in.write_enable = '1' then
                                assert not(is_x(w_in.write_data)) and not(is_x(w_in.write_reg)) severity failure;
-                               report "Writing " & to_hstring(w_in.write_data) & " to " & to_hstring(w_in.write_reg);
+                               report "Writing GPR " & to_hstring(w_in.write_reg) & " " & to_hstring(w_in.write_data);
                                registers(to_integer(unsigned(w_in.write_reg))) <= w_in.write_data;
                        end if;
                        if w_in.write_enable2 = '1' then
                                assert not(is_x(w_in.write_data2)) and not(is_x(w_in.write_reg2)) severity failure;
-                               report "Writing " & to_hstring(w_in.write_data2) & " to " & to_hstring(w_in.write_reg2);
+                               report "Writing GPR " & to_hstring(w_in.write_reg2) & " " & to_hstring(w_in.write_data2);
                                registers(to_integer(unsigned(w_in.write_reg2))) <= w_in.write_data2;
                        end if;
                end if;
@@ -42,9 +42,15 @@ begin
        -- asynchronous reads
        register_read_0: process(all)
        begin
-               report "read " & to_hstring(d_in.read1_reg) & " " & to_hstring(registers(to_integer(unsigned(d_in.read1_reg))));
-               report "read " & to_hstring(d_in.read2_reg) & " " & to_hstring(registers(to_integer(unsigned(d_in.read2_reg))));
-               report "read " & to_hstring(d_in.read3_reg) & " " & to_hstring(registers(to_integer(unsigned(d_in.read3_reg))));
+               if d_in.read1_enable = '1' then
+                       report "Reading GPR " & to_hstring(d_in.read1_reg) & " " & to_hstring(registers(to_integer(unsigned(d_in.read1_reg))));
+               end if;
+               if d_in.read2_enable = '1' then
+                       report "Reading GPR " & to_hstring(d_in.read2_reg) & " " & to_hstring(registers(to_integer(unsigned(d_in.read2_reg))));
+               end if;
+               if d_in.read3_enable = '1' then
+                       report "Reading GPR " & to_hstring(d_in.read3_reg) & " " & to_hstring(registers(to_integer(unsigned(d_in.read3_reg))));
+               end if;
                d_out.read1_data <= registers(to_integer(unsigned(d_in.read1_reg)));
                d_out.read2_data <= registers(to_integer(unsigned(d_in.read2_reg)));
                d_out.read3_data <= registers(to_integer(unsigned(d_in.read3_reg)));