flake.nix

@@ -11,8 +11,7 @@
 
           verilator = import ./verilator.nix pkgs ;
 
-          vflags = ''-Wpedantic -Wwarn-lint -Wwarn-style -CFLAGS "-Wpedantic -std=c++20"'';
+          vflags = "-Wpedantic -Wwarn-lint -Wwarn-style";
-
           verilate-src = cmd: ''
             cp -r ${./verilog-src} ./verilog-src
             cp -r ${./simulation} ./simulation
@@ -26,7 +25,7 @@
           '';
 
           alu-sim = pkgs.runCommandCC "alu-sim" {} ''
-            ${verilate-src "--cc --build --exe ./simulation/tester.cpp ./simulation/test_alu.cpp"}
+            ${verilate-src "--cc --build --exe ./simulation/test_alu.cpp"}
             mv obj_dir "$out"
             mkdir "$out/bin" && cp "$out/Valu" "$out/bin/alu-sim"
           '';

simulation/test_alu.cpp

@@ -1,96 +1,18 @@
 #include "Valu.h"
 #include "verilated.h"
-#include "tester.hpp"
+#include <iostream>
 
 int main(int argc, char **argv) {
     VerilatedContext *vctx = new VerilatedContext;
+
     Valu *valu = new Valu(vctx);
+    valu->A = 0x2137;
+    valu->B = 0x1234;
 
-    Tester alu_t("alu");
+    valu->op = 0b000;
-    {
+    valu->eval();
-        Tester add_t(&alu_t, "add");
+    printf("A = %04x + B = %04x = O = %04x\n", valu->A, valu->B, valu->O);
-
+    valu->op = 0b001;
-        {
+    valu->eval();
-            Tester add_case(&add_t, "0x2137+0x1234");
+    printf("A = %04x - B = %04x = O = %04x\n", valu->A, valu->B, valu->O);
-            valu->op = 0b000;
-            valu->A = 0x2137;
-            valu->B = 0x1234;
-            valu->eval();
-            add_case.assert_eq("O == 0x336b", valu->O, 0x336b);
-            add_case.assert_eq("no overflow", valu->Fflow, 0x0);
-            add_case.assert_eq("no Fzero", valu->Fzero, 0x0);
-        }
-
-        {
-            Tester add_case(&add_t, "0x9+0x10");
-            valu->op = 0b000;
-            valu->A = 0x9;
-            valu->B = 0x10;
-            valu->eval();
-            add_case.assert_eq("O == 0x19", valu->O, 0x19);
-            add_case.assert_eq("no overflow", valu->Fflow, 0x0);
-            add_case.assert_eq("no Fzero", valu->Fzero, 0x0);
-        }
-
-        {
-            Tester add_case(&add_t, "0xffffffff+0x1");
-            valu->op = 0b000;
-            valu->A = 0xffffffff;
-            valu->B = 0x1;
-            valu->eval();
-            add_case.assert_eq("O == 0x0", valu->O, 0x0);
-            add_case.assert_eq("has overflow", valu->Fflow, 0x1);
-            add_case.assert_eq("has Fzero", valu->Fzero, 0x1);
-        }
-    }
-
-    {
-        Tester sub_t(&alu_t, "sub");
-
-        {
-            Tester sub_case(&sub_t, "0x2137-0x0420");
-            valu->op = 0b001;
-            valu->A = 0x2137;
-            valu->B = 0x0420;
-            valu->eval();
-            sub_case.assert_eq("O == 0x1d17", valu->O, 0x1d17);
-            sub_case.assert_eq("no underflow", valu->Fflow, 0x0);
-            sub_case.assert_eq("no Fzero", valu->Fzero, 0x0);
-        }
-
-        {
-            Tester sub_case(&sub_t, "0x100-0x200");
-            valu->op = 0b001;
-            valu->A = 0x100;
-            valu->B = 0x200;
-            valu->eval();
-            sub_case.assert_eq("O == 0xffffff00", valu->O, 0xffffff00);
-            sub_case.assert_eq("has underflow", valu->Fflow, 0x1);
-            sub_case.assert_eq("no Fzero", valu->Fzero, 0x0);
-        }
-
-        {
-            Tester sub_case(&sub_t, "0x0-0x1");
-            valu->op = 0b001;
-            valu->A = 0x0;
-            valu->B = 0x1;
-            valu->eval();
-            sub_case.assert_eq("O == 0xffffffff", valu->O, 0xffffffff);
-            sub_case.assert_eq("has underflow", valu->Fflow, 0x1);
-            sub_case.assert_eq("no Fzero", valu->Fzero, 0x0);
-        }
-
-        {
-            Tester sub_case(&sub_t, "0x20-0x20");
-            valu->op = 0b001;
-            valu->A = 0x20;
-            valu->B = 0x20;
-            valu->eval();
-            sub_case.assert_eq("O == 0x0", valu->O, 0x0);
-            sub_case.assert_eq("no underflow", valu->Fflow, 0x0);
-            sub_case.assert_eq("has Fzero", valu->Fzero, 0x1);
-        }
-    }
-
-
 }

simulation/tester.cpp

@@ -1,120 +0,0 @@
-#include <iostream>
-#include <optional>
-#include "tester.hpp"
-
-const std::string ANSI_RESET = "\033[0m";
-const std::string ANSI_DARK = "\033[38;5;8m";
-const std::string ANSI_BLUE = "\033[38;5;6m";
-const std::string ANSI_GREEN = "\033[38;5;2m";
-const std::string ANSI_RED = "\033[38;5;1m";
-const std::string ANSI_YELLOW = "\033[38;5;11m";
-
-int Tester::depth() {
-    int depth = 0;
-    for (std::optional<Tester*> at = this; at.has_value(); at = (*at)->parent) {
-        depth++;
-    }
-    return depth;
-}
-
-std::string Tester::full_name() {
-    std::string full_name(name);
-    std::optional<Tester*> at = parent;
-    while (at.has_value()) {
-        full_name.insert(0, " ");
-        full_name.insert(0, (*at)->name);
-        at = (*at)->parent;
-    }
-    return full_name;
-}
-
-std::string Tester::prefix() {
-    std::string line = full_name();
-    line.insert(0, "[ ");
-
-    line.append(" ]");
-
-    int wanted_len = 10 * depth();
-    if (line.length() == wanted_len) {
-        line.insert(0, ANSI_BLUE);
-        line.append(ANSI_RESET);
-        line.append(" ");
-        return line;
-    } else if (line.length() > wanted_len) {
-        line.append("\n");
-        line.append(ANSI_DARK);
-        for (int i = 0; i < wanted_len; i++)
-            line.append("—");
-
-        line.insert(0, ANSI_BLUE);
-        line.append(ANSI_RESET);
-        line.append(" ");
-        return line;
-    } else {
-        int extra = wanted_len - line.length();
-        line.append(" ");
-        line.append(ANSI_DARK);
-        for (int i = 1; i < extra; i++)
-            line.append("—");
-
-        line.insert(0, ANSI_BLUE);
-        line.append(ANSI_RESET);
-        line.append(" ");
-        return line;
-    }
-}
-
-void Tester::intro() {
-    std::cout << prefix() << "=== " << ANSI_YELLOW << "start" << ANSI_RESET << std::endl;
-}
-
-Tester::Tester(std::string test_name) :
-    parent(),
-    name(test_name),
-    succeeded(0), failed(0)
-{
-    intro();
-}
-
-Tester::Tester(Tester* tester_parent, std::string test_name) :
-    parent(tester_parent),
-    name(test_name),
-    succeeded(0), failed(0)
-{
-    intro();
-}
-
-void Tester::assert_eq_str(std::string test_name, bool correct, std::string got_s, std::string expected_s) {
-    std::cout << prefix() << "- " << test_name;
-    if (correct) {
-        std::cout << " " << ANSI_GREEN << "succeded" << ANSI_RESET << std::endl;
-        for (std::optional<Tester*> at = this; at.has_value(); at = (*at)->parent) {
-            (*at)->succeeded++;
-        }
-    } else {
-
-        std::cout << " " << ANSI_RED << "failed - got " << got_s << ", expected " << expected_s << ANSI_RESET << std::endl;
-        for (std::optional<Tester*> at = this; at.has_value(); at = (*at)->parent) {
-            (*at)->failed++;
-        }
-    }
-}
-
-Tester::~Tester() {
-    finish();
-}
-
-void Tester::finish() {
-    char n_cases_s[10], n_succeeded_s[10], n_failed_s[10];
-    snprintf(n_cases_s, sizeof n_cases_s, "%d", succeeded + failed);
-    snprintf(n_succeeded_s, sizeof n_succeeded_s, "%d", succeeded);
-    snprintf(n_failed_s, sizeof n_failed_s, "%d", failed);
-    if (failed == 0) {
-        // printf("[ %s ] - %sall succeeded%s, out of %d total\n", name.c_str(), ANSI_GREEN.c_str(), ANSI_RESET.c_str(), succeeded + failed);
-        std::cout << prefix() << "=== " << ANSI_GREEN << "all succeeded" << ANSI_RESET << ", out of " << n_cases_s << " total" << std::endl;
-    } else {
-        std::cout << prefix() << "=== " << ANSI_RED << n_failed_s << " failed" << ANSI_RESET << ", " << ANSI_GREEN << n_succeeded_s << " succeeded" << ANSI_RESET << " out of " << n_cases_s << " total" << std::endl;
-        // printf("[ %s ] - %s%d failed, %d succeeded%s, out of %d total\n", name.c_str(), ANSI_RED.c_str(), failed, succeeded, ANSI_RESET.c_str(), succeeded + failed);
-    }
-}
-

simulation/tester.hpp

@@ -1,37 +0,0 @@
-#ifndef tester_hpp_INCLUDED
-#define tester_hpp_INCLUDED
-
-class Tester {
-
-    public:
-        Tester(std::string test_name);
-
-        Tester(Tester* tester_parent, std::string test_name);
-
-        template<typename T, typename U>
-        void assert_eq(std::string test_name, T got, U expected) {
-            char got_s[10], expected_s[10];
-            snprintf(got_s, sizeof got_s, "%08x", got);
-            snprintf(expected_s, sizeof expected_s, "%08x", expected);
-
-            assert_eq_str(test_name, got == expected, got_s, expected_s);
-        }
-        void assert_eq_str(std::string test_name, bool correct, std::string got_s, std::string expected_s);
-
-
-        ~Tester();
-
-        void intro();
-        void finish();
-
-    private:
-        std::optional<Tester*> parent;
-        std::string name;
-        int succeeded, failed;
-
-        int depth();
-        std::string full_name();
-        std::string prefix();
-};
-
-#endif // tester_hpp_INCLUDED

verilog-src/alu.v

@@ -15,17 +15,14 @@ module alu(
   input [31:0] B,
   input [2:0] op,
   output [31:0] O,
-  output Fflow,
+  output Cout,
   output Fzero
 );
 
 wire subtraction = op == 3'b001;
 wire [31:0] adder_B = subtraction ? ~B : B;
-wire adder_cout;
 
-carry_select_adder a(A, adder_B, subtraction, O, adder_cout);
+carry_select_adder a(A, adder_B, subtraction, O, Cout);
-
+assign Fzero = & O;
-assign Fflow = subtraction ? ~adder_cout : adder_cout;
-assign Fzero = ~ (| O);
 
 endmodule