added register file

8 files changed, 145 insertions, 55 deletions

diff --git a/gentestvec/gentestvec_register_file.c b/gentestvec/gentestvec_register_file.c
new file mode 100644
index 0000000..2533772
--- /dev/null
+++ b/gentestvec/gentestvec_register_file.c
@@ -0,0 +1,48 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+uint32_t registers[32];
+
+uint32_t read_reg(uint32_t addr) { return addr == 0 ? 0 : registers[addr]; }
+
+void write_reg(uint32_t addr, uint32_t data, bool we) {
+  if (addr != 0 && we)
+    registers[addr] = data;
+}
+
+void test(uint32_t addr_rs0, uint32_t addr_rs1, uint32_t addr_rd2,
+          uint32_t data_rd2, bool we) {
+  write_reg(addr_rd2, data_rd2, we);
+  uint32_t data_rs0 = read_reg(addr_rs0);
+  uint32_t data_rs1 = read_reg(addr_rs1);
+  printf("%08X_%08X__%08X_%08X__%08X_%08X_%01X\n", addr_rs0, data_rs0, addr_rs1,
+         data_rs1, addr_rd2, data_rd2, we);
+}
+
+void tests(int num) {
+  for (int i = 0; i < num; ++i) {
+    uint32_t addr_rs0 = ((uint32_t)((rand() << 16) | rand())) % 32;
+    uint32_t addr_rs1 = ((uint32_t)((rand() << 16) | rand())) % 32;
+    uint32_t addr_rd2 = ((uint32_t)((rand() << 16) | rand())) % 32;
+    uint32_t data_rd2 = ((uint32_t)((rand() << 16) | rand()));
+    bool we = ((uint32_t)rand()) % 2;
+    test(addr_rs0, addr_rs1, addr_rd2, data_rd2, we);
+  }
+}
+
+int main(int argc, const char *argv[]) {
+  srand(time(NULL));
+  for (int i = 0; i < 32; ++i)
+    registers[0] = 0;
+
+  for (int i = 0; i < 32; ++i)
+    test(i, i, 0, 0, false);
+
+  for (int i = 0; i < 32; ++i)
+    test(i, i, i, 0xffffffff, true);
+
+  tests(1000);
+  return 0;
+}
diff --git a/include/log2.vh b/include/log2.vh
new file mode 100644
index 0000000..097061d
--- /dev/null
+++ b/include/log2.vh
@@ -0,0 +1,12 @@
+function integer log2;
+  input integer value;
+  integer temp;
+  begin
+    log2 = 0;
+    temp = value - 1;
+    while (temp > 0) begin
+      log2 = log2 + 1;
+      temp = temp >> 1;
+    end
+  end
+endfunction
diff --git a/sim/testbench_alu.v b/sim/testbench_alu.v
index 068efc3..45cce1b 100644
--- a/sim/testbench_alu.v
+++ b/sim/testbench_alu.v
@@ -76,11 +76,11 @@ module testbench_alu();
   
 
   alu #(.N(32)) alu (
-    .alu_src0(a),
-    .alu_src1(b),
-    .alu_op(op),
-    .alu_result(result),
-    .alu_zero(zero)
+    .src0(a),
+    .src1(b),
+    .op(op),
+    .result(result),
+    .zero(zero)
   );
 
 endmodule
diff --git a/src/alu.v b/src/alu.v
index 2eaf2b0..e90694b 100644
--- a/src/alu.v
+++ b/src/alu.v
@@ -1,43 +1,43 @@
 module alu #(
   parameter N = 32
 )(
-  input [N-1:0] alu_src0, alu_src1,
-  input [3:0] alu_op, // alu_op[3:2] 00: ARITHMETIC, 01: LOGIC, 10: SHIFT 
-  output reg [N-1:0] alu_result,
-  output alu_zero
+  input [N-1:0] src0, src1,
+  input [3:0] op, // alu_op[3:2] 00: ARITHMETIC, 01: LOGIC, 10: SHIFT 
+  output reg [N-1:0] result,
+  output zero
 );
 
 wire [N-1:0] arithmetic_result, logic_result, shift_result;
 
 arithmetic_unit #(.N(N)) au (
-  .au_src0(alu_src0),
-  .au_src1(alu_src1),
-  .au_op(alu_op[1:0]),
-  .au_result(arithmetic_result)
+  .src0(src0),
+  .src1(src1),
+  .op(op[1:0]),
+  .result(arithmetic_result)
 );
 
 logic_unit #(.N(N)) lu (
-  .lu_src0(alu_src0),
-  .lu_src1(alu_src1),
-  .lu_op(alu_op[1:0]),
-  .lu_result(logic_result)
+  .src0(src0),
+  .src1(src1),
+  .op(op[1:0]),
+  .result(logic_result)
 );
 
 shift_unit #(.N(N)) su (
-  .su_src0(alu_src0),
-  .su_shamt(alu_src1),
-  .su_op(alu_op[1:0]),
-  .su_result(shift_result)
+  .src0(src0),
+  .shamt(src1),
+  .op(op[1:0]),
+  .result(shift_result)
 );
 
 always @ (*) begin
-  case (alu_op[3:2])
-    2'b00: alu_result <= arithmetic_result;
-    2'b01: alu_result <= logic_result;
-    2'b10: alu_result <= shift_result;
+  case (op[3:2])
+    2'b00: result <= arithmetic_result;
+    2'b01: result <= logic_result;
+    2'b10: result <= shift_result;
   endcase
 end
 
-assign alu_zero = ~|alu_result;
+assign zero = ~|result;
 
 endmodule
diff --git a/src/arithmetic_unit.v b/src/arithmetic_unit.v
index 71255c2..59f5cae 100644
--- a/src/arithmetic_unit.v
+++ b/src/arithmetic_unit.v
@@ -1,23 +1,23 @@
 module arithmetic_unit #(
   parameter N = 32
 )(
-  input [N-1:0] au_src0, au_src1,
-  input [1:0] au_op, // 00: ADD, 01: SUB, 11: SLT
-  output [N-1:0] au_result
+  input [N-1:0] src0, src1,
+  input [1:0] op, // 00: ADD, 01: SUB, 11: SLT
+  output [N-1:0] result
 );
 
-wire [N-1:0] au_src1_inv, au_sum;
-wire au_cin, au_src0_lt_src1, au_overflow;
+wire [N-1:0] src1_inv, sum;
+wire cin, src0_lt_src1, overflow;
 
-assign au_src1_inv = au_op[0] ? ~au_src1 : au_src1;
-assign au_cin = au_op[0];
+assign src1_inv = op[0] ? ~src1 : src1;
+assign cin = op[0];
 
-assign au_sum = au_src0 + au_src1_inv + au_cin;
+assign sum = src0 + src1_inv + cin;
 
-assign au_overflow = ~(au_src0[N-1] ^ au_src1[N-1] ^ au_op[0]) & (au_src0[N-1] ^ au_sum[N-1]);
+assign overflow = ~(src0[N-1] ^ src1[N-1] ^ op[0]) & (src0[N-1] ^ sum[N-1]);
 
-assign au_src0_lt_src1 = au_overflow ^ au_sum[N-1];
+assign src0_lt_src1 = overflow ^ sum[N-1];
 
-assign au_result = au_op[1] ? {{(N-1){1'b0}}, au_src0_lt_src1} : au_sum;
+assign result = op[1] ? {{(N-1){1'b0}}, src0_lt_src1} : sum;
 
 endmodule
diff --git a/src/logic_unit.v b/src/logic_unit.v
index 85c9137..0bbd642 100644
--- a/src/logic_unit.v
+++ b/src/logic_unit.v
@@ -1,17 +1,17 @@
 module logic_unit #(
   parameter N = 32
 )(
-  input [N-1:0] lu_src0, lu_src1,
-  input [1:0] lu_op, // 00: AND, 01: OR, 10: XOR
-  output reg [N-1:0] lu_result
+  input [N-1:0] src0, src1,
+  input [1:0] op, // 00: AND, 01: OR, 10: XOR
+  output reg [N-1:0] result
 );
   
-  always @ (*) begin
-    case (lu_op)
-      2'b00: lu_result <= lu_src0 & lu_src1;
-      2'b01: lu_result <= lu_src0 | lu_src1;
-      2'b10: lu_result <= lu_src0 ^ lu_src1;
-    endcase
-  end
+always @ (*) begin
+  case (op)
+  2'b00: result <= src0 & src1;
+  2'b01: result <= src0 | src1;
+  2'b10: result <= src0 ^ src1;
+  endcase
+end
 
 endmodule
diff --git a/src/register_file.v b/src/register_file.v
new file mode 100644
index 0000000..81bce34
--- /dev/null
+++ b/src/register_file.v
@@ -0,0 +1,30 @@
+module register_file #(
+  parameter N = 32,
+  parameter XLEN = 32
+)(
+  input clk, rst, we,
+  input [log2(N)-1:0] addr_rs0, addr_rs1, addr_rd2,
+  input [N-1:0] data_rd2,
+  output [N-1:0] data_rs0, data_rs1
+);
+
+`include "include/log2.vh"
+
+reg [N-1:0] registers[XLEN-1:1];
+
+assign data_rs0 = (addr_rs0 == 0) ? 0 : registers[addr_rs0];
+assign data_rs1 = (addr_rs1 == 0) ? 0 : registers[addr_rs1];
+
+
+
+integer i;
+always @(posedge clk) begin
+  if (rst) begin
+    for (i = 1; i < XLEN; i = i + 1)
+      registers[i] <= 0;
+  end else if (we && (addr_rd2 != 0)) begin
+    registers[addr_rd2] <= data_rd2;
+  end
+end
+
+endmodule
diff --git a/src/shift_unit.v b/src/shift_unit.v
index 372fec0..d0aa9d3 100644
--- a/src/shift_unit.v
+++ b/src/shift_unit.v
@@ -1,17 +1,17 @@
 module shift_unit #(
   parameter N = 32
 )(
-  input signed [N-1:0] su_src0,
-  input  [N-1:0] su_shamt,
-  input [1:0] su_op, // 00: SLL, 01: SRL, 11: SRA 
-  output reg [N-1:0] su_result
+  input signed [N-1:0] src0,
+  input  [N-1:0] shamt,
+  input [1:0] op, // 00: SLL, 01: SRL, 11: SRA
+  output reg [N-1:0] result
 );
 
 always @ (*) begin
-  case (su_op)
-    2'b00: su_result <= su_src0 << su_shamt % N;
-    2'b01: su_result <= su_src0 >> su_shamt % N;
-    2'b11: su_result <= su_src0 >>> su_shamt % N;
+  case (op)
+  2'b00: result <= src0 << shamt % N;
+  2'b01: result <= src0 >> shamt % N;
+  2'b11: result <= src0 >>> shamt % N;
   endcase
 end