Pretty up the testing framework, split into files

flake.nix

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

simulation/test_alu.cpp

@@ -1,18 +1,96 @@
 #include "Valu.h"
 #include "verilated.h"
-#include <iostream>
+#include "tester.hpp"
 
 int main(int argc, char **argv) {
     VerilatedContext *vctx = new VerilatedContext;
-
     Valu *valu = new Valu(vctx);
+
+    Tester alu_t("alu");
+    {
+        Tester add_t(&alu_t, "add");
+
+        {
+            Tester add_case(&add_t, "0x2137+0x1234");
+            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();
-    printf("A = %04x + B = %04x = O = %04x\n", valu->A, valu->B, valu->O);
+            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();
-    printf("A = %04x - B = %04x = O = %04x\n", valu->A, valu->B, valu->O);
+            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

@@ -0,0 +1,120 @@
+#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

@@ -0,0 +1,37 @@
+#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

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