From 6f7dbe752887e783e555cd6dcce79962b085b9ef Mon Sep 17 00:00:00 2001
From: Artem Zyktin <zyktin.a.a@gmail.com>
Date: Tue, 2 Jun 2026 05:51:08 +0800
Subject: [PATCH] Add negative operator

---
 src/naive/naive_vec4.h              |  5 ++++
 src/tenvex/expressions/core.h       | 12 ++++++++++
 src/tenvex/expressions/dot3_impl.h  |  2 +-
 src/tenvex/expressions/neg.h        | 36 +++++++++++++++++++++++++++++
 src/tenvex/expressions/neg_impl.hpp | 36 +++++++++++++++++++++++++++++
 src/tenvex/expressions/vec4.h       |  3 ---
 src/tenvex/tenvex.h                 |  1 +
 7 files changed, 91 insertions(+), 4 deletions(-)
 create mode 100644 src/tenvex/expressions/neg.h
 create mode 100644 src/tenvex/expressions/neg_impl.hpp

diff --git a/src/naive/naive_vec4.h b/src/naive/naive_vec4.h
index 910efd8..ae3ff46 100644
--- a/src/naive/naive_vec4.h
+++ b/src/naive/naive_vec4.h
@@ -89,4 +89,9 @@ inline bool approx_eq(vec4 a, vec4 b, float eps = 1e-6f) noexcept
 		&& std::fabs(a.w() - b.w()) <= eps;
 }
 
+[[nodiscard]] inline vec4 operator-(vec4 v) noexcept
+{
+	return { -v.x(), -v.y(), -v.z(), -v.w() };
+}
+
 }
\ No newline at end of file
diff --git a/src/tenvex/expressions/core.h b/src/tenvex/expressions/core.h
index 50ef0d7..dee9a82 100644
--- a/src/tenvex/expressions/core.h
+++ b/src/tenvex/expressions/core.h
@@ -13,6 +13,12 @@
 namespace tnvx::detail
 {
 
+[[nodiscard]] TNVX_INLINE
+float to_float(vf4 v)
+{
+	return _mm_cvtss_f32(v);
+}
+
 [[nodiscard]] TNVX_INLINE
 bool eq(vf4 a, vf4 b)
 {
@@ -39,6 +45,12 @@ float get_lane(vf4 v) noexcept
 	return _mm_cvtss_f32(_mm_shuffle_ps(v, v, _MM_SHUFFLE(0, 0, 0, lane)));
 }
 
+[[nodiscard]] TNVX_INLINE
+vf4 neg(vf4 v) noexcept
+{
+	return _mm_xor_ps(v, _mm_set1_ps(-0.0f));
+}
+
 [[nodiscard]] TNVX_INLINE
 vf4 add(vf4 l, vf4 r) noexcept
 {
diff --git a/src/tenvex/expressions/dot3_impl.h b/src/tenvex/expressions/dot3_impl.h
index 03cadd6..3c3f864 100644
--- a/src/tenvex/expressions/dot3_impl.h
+++ b/src/tenvex/expressions/dot3_impl.h
@@ -24,7 +24,7 @@ template<vec_expr L, vec_expr R>
 TNVX_INLINE
 Dot3<L, R>::operator float() const noexcept
 {
-	return _mm_cvtss_f32(eval());
+	return detail::to_float(eval());
 }
 
 template<vec_expr L, vec_expr R>
diff --git a/src/tenvex/expressions/neg.h b/src/tenvex/expressions/neg.h
new file mode 100644
index 0000000..4056851
--- /dev/null
+++ b/src/tenvex/expressions/neg.h
@@ -0,0 +1,36 @@
+#pragma once
+
+#include "core.h"
+#include "expression.h"
+#include "traits.h"
+#include "concepts.h"
+
+namespace tnvx
+{
+
+template<expression E>
+struct Neg : Expr<Neg<E>>
+{
+	TNVX_INLINE
+	explicit Neg(const E& TNVX_RESTRICT e) noexcept;
+
+	[[nodiscard]] TNVX_INLINE
+	vf4 eval() const noexcept;
+
+	[[nodiscard]] TNVX_INLINE
+	operator float() const noexcept requires scalar_expr<E>;
+
+private:
+	tnvx_ref_or_value_t<E> _e;
+};
+
+template<vec_expr E> inline constexpr bool is_vec_expr<Neg<E>> = true;
+template<scalar_expr E> inline constexpr bool is_scalar_expr<Neg<E>> = true;
+
+template<expression E>
+[[nodiscard]] TNVX_INLINE
+Neg<E> operator-(const E& e) noexcept;
+
+}
+
+#include "neg_impl.hpp"
diff --git a/src/tenvex/expressions/neg_impl.hpp b/src/tenvex/expressions/neg_impl.hpp
new file mode 100644
index 0000000..ecf30f1
--- /dev/null
+++ b/src/tenvex/expressions/neg_impl.hpp
@@ -0,0 +1,36 @@
+#pragma once
+
+#include "neg.h"
+
+namespace tnvx
+{
+
+template<expression E>
+TNVX_INLINE
+tnvx::Neg<E>::Neg(const E& TNVX_RESTRICT e) noexcept
+	: _e(e)
+{
+}
+
+template<expression E>
+TNVX_INLINE
+vf4 Neg<E>::eval() const noexcept
+{
+	return detail::neg(_e.eval());
+}
+
+template<expression E>
+TNVX_INLINE
+Neg<E>::operator float() const noexcept requires scalar_expr<E>
+{
+	return detail::to_float(eval());
+}
+
+template<expression E>
+TNVX_INLINE
+Neg<E> operator-(const E& e) noexcept
+{
+	return Neg<E>(e);
+}
+
+}
diff --git a/src/tenvex/expressions/vec4.h b/src/tenvex/expressions/vec4.h
index 82960ec..30be4e7 100644
--- a/src/tenvex/expressions/vec4.h
+++ b/src/tenvex/expressions/vec4.h
@@ -35,9 +35,6 @@ struct alignas(16) vec4 : Expr<vec4>
 	[[nodiscard]] TNVX_INLINE
 	vf4 eval() const noexcept;
 
-	[[nodiscard]] TNVX_INLINE
-	vec4 operator-() const noexcept;
-
 private:
 
 	vf4 _data;
diff --git a/src/tenvex/tenvex.h b/src/tenvex/tenvex.h
index f87fc6b..ad2e4ba 100644
--- a/src/tenvex/tenvex.h
+++ b/src/tenvex/tenvex.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include "expressions/neg.h"
 #include "expressions/add.h"
 #include "expressions/sub.h"
 #include "expressions/scalar.h"