From 5f82fe975c94780526517c70e3fa3946382795f4 Mon Sep 17 00:00:00 2001
From: DarkSharpness <2040703891@qq.com>
Date: Tue, 9 Jul 2024 23:19:36 +0800
Subject: [PATCH] feat(bit): add a demo and add some functions for the bit
 class

---
 demo/bit.cpp                    | 39 +++++++++++++++++++++++++++++++++
 demo/{demo.cpp => hardware.cpp} |  4 +---
 include/bit.h                   | 12 +++++++++-
 3 files changed, 51 insertions(+), 4 deletions(-)
 create mode 100644 demo/bit.cpp
 rename demo/{demo.cpp => hardware.cpp} (90%)

diff --git a/demo/bit.cpp b/demo/bit.cpp
new file mode 100644
index 0000000..956caea
--- /dev/null
+++ b/demo/bit.cpp
@@ -0,0 +1,39 @@
+#include "../include/tools"
+
+signed main() {
+    [[maybe_unused]]
+    Bit <1> a; // Create a 1-bit object, default to 0
+
+    Bit <10> b(10); // Create a 10-bit object
+
+    auto ref = b.slice <4, 2> (); // A copy of [2, 3, 4] bit
+
+    std::cout << b << std::endl; // 10
+
+    b.set <3, 1> (ref); // Set [1, 2, 3] bit to [2, 3, 4] bit
+
+    std::cout << b << std::endl; // 4
+
+    b.set <0> (~a); // Set the 0-th bit to ~a (= 1 in this case)
+
+    std::cout << b << std::endl; // 5
+
+    auto sec = b.slice <2> (); // A copy of the 2-th bit (= 1 in this case)
+
+    auto d = sec.zero_extend(); // Zero extend (default to 32-bit)
+
+    std::cout << d << std::endl; // 1
+
+    auto c = sec.sign_extend <3> (); // Sign extend (default to 32-bit)
+
+    std::cout << c << std::endl; // 7
+
+    // c + d;   // Error: different size
+    // a += 1;  // Error: no assignment-operation operator
+
+    auto e = b - 1; // normal integer can be assumed as any size
+
+    std::cout << e << std::endl; // 4
+
+    return 0;
+}
diff --git a/demo/demo.cpp b/demo/hardware.cpp
similarity index 90%
rename from demo/demo.cpp
rename to demo/hardware.cpp
index 9060079..a7d09ae 100644
--- a/demo/demo.cpp
+++ b/demo/hardware.cpp
@@ -19,9 +19,7 @@ struct MyModule : Input, Output, private Content {
     using Tags = SyncTags <Input, Output, Content>;
     friend class Visitor;
 
-    void demo() {
-        this->d <= this->a + this->b;
-    }
+    void demo() { this->d <= this->a + this->b; }
 };
 
 signed main() {
diff --git a/include/bit.h b/include/bit.h
index ba5e8e2..38881e6 100644
--- a/include/bit.h
+++ b/include/bit.h
@@ -26,7 +26,7 @@ struct Bit {
   public:
     static constexpr std::size_t _Bit_Len = _Nm;
 
-    constexpr Bit(target_size_t data = 0) : _M_data(data) {}
+    constexpr Bit(target_size_t data = {}) : _M_data(data) {}
 
     template <std::size_t ..._Lens>
     constexpr Bit(Bit<_Lens> ...args) requires ((_Lens + ...) == _Nm) :
@@ -54,6 +54,16 @@ struct Bit {
 
     constexpr operator target_size_t() const { return this->_M_data; }
 
+    template <std::size_t _Hi, std::size_t _Lo = _Hi>
+    constexpr auto set(Bit <_Hi - _Lo + 1> val) {
+        static_cast <void> (this->slice<_Hi, _Lo>());
+        const auto mask = // Mask those bit in the middle
+            (target_size_t(1) << (_Hi + 1)) - (target_size_t(1) << _Lo);
+        const auto data = // Set those bit in the middle
+            static_cast <target_size_t> (val) << _Lo;
+        this->_M_data = (this->_M_data & ~mask) | data;
+    }
+
     template <std::size_t _Hi, std::size_t _Lo = _Hi>
     constexpr auto slice() const -> Bit <_Hi - _Lo + 1> {
         static_assert(_Lo <= _Hi, "Bit::slice: _Lo should be no greater than _Hi");