From 06bd50ea83f43f30de9a27c0f41b001001fd49bd Mon Sep 17 00:00:00 2001
From: Javier Cicchelli <javier@rock-n-code.com>
Date: Sat, 25 Jul 2026 10:12:17 +0200
Subject: [PATCH] Implemented a "posix_memalign" shim on Support in the
 PlayDate binding target for Embedded Swift on device.

---
 Sources/PlayDate/Support.swift | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/Sources/PlayDate/Support.swift b/Sources/PlayDate/Support.swift
index 26f7dbf..623f87f 100644
--- a/Sources/PlayDate/Support.swift
+++ b/Sources/PlayDate/Support.swift
@@ -67,3 +67,22 @@ extension String {
         return buffer
     }
 }
+
+#if hasFeature(Embedded) && !os(macOS)
+/// The Embedded Swift runtime allocates through `posix_memalign(3)`, which
+/// the Playdate device C library does not provide. Memory comes from
+/// `malloc`, which the SDK's setup code routes to the firmware allocator;
+/// that allocator hands out sufficiently aligned blocks, so alignment is
+/// only asserted, not adjusted.
+@_cdecl("posix_memalign")
+public func posix_memalign(
+    _ memptr: UnsafeMutablePointer<UnsafeMutableRawPointer?>,
+    _ alignment: Int,
+    _ size: Int
+) -> CInt {
+    guard let allocation = malloc(size + alignment - 1) else { fatalError() }
+    precondition(Int(bitPattern: allocation) % alignment == 0)
+    memptr.pointee = allocation
+    return 0
+}
+#endif