From ed7c449ad24a1a6a6a50c8233d9a5bafb23fe413 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Gr=C3=A9goire?= <loic@gregoire.dev>
Date: Sun, 5 Jul 2026 00:28:04 -0400
Subject: [PATCH] rtl: add CachePadded

---
 src/rtl/cache_padded.zig | 18 ++++++++++++++++++
 src/rtl/root.zig         |  1 +
 2 files changed, 19 insertions(+)
 create mode 100644 src/rtl/cache_padded.zig

diff --git a/src/rtl/cache_padded.zig b/src/rtl/cache_padded.zig
new file mode 100644
index 0000000..ba7aaf7
--- /dev/null
+++ b/src/rtl/cache_padded.zig
@@ -0,0 +1,18 @@
+const std = @import("std");
+
+/// Type padded to a cache line.
+pub fn CachePadded(comptime T: type) type {
+    return struct {
+        const cache_line = std.atomic.cache_line;
+        const value_size = @sizeOf(T);
+        const padded_size = std.mem.alignForward(usize, value_size, cache_line);
+        const pad = padded_size - value_size;
+
+        value: T align(cache_line),
+        _pad: [pad]u8 = undefined,
+
+        pub fn init(val: T) @This() {
+            return .{ .value = val };
+        }
+    };
+}
diff --git a/src/rtl/root.zig b/src/rtl/root.zig
index 3404729..30385e2 100644
--- a/src/rtl/root.zig
+++ b/src/rtl/root.zig
@@ -15,6 +15,7 @@ pub const BitMap = @import("bitmap.zig").BitMap;
 pub const AtomicBitMap = @import("bitmap.zig").AtomicBitMap;
 pub const HandoffList = @import("handoff.zig").HandoffList;
 pub const LinkerSet = @import("linker_set.zig").LinkerSet;
+pub const CachePadded = @import("cache_padded.zig").CachePadded;
 
 /// Asserts that a given type `T` matches the schema declared by `I`.
 /// This includes public methods and fields.