Add arm64_32 PSA.

featherless · Oct 3, 2024 · a8c8372 · a8c8372
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diff --git a/Sources/Site/Posts/2024/10/2024-10-02-arm64_32-PSA.md b/Sources/Site/Posts/2024/10/2024-10-02-arm64_32-PSA.md
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+# Reminder: Apple Watches use 32 bit pointers
+
+> Since the Series 4 was introduced in 2018, all new Apple Watches have been arm64_32. The last
+> Apple Watch to be armv7k was the Series 3.
+
+Source: https://forums.developer.apple.com/forums/thread/759363
+
+What is arm64_32? It's a 64 bit operating system that runs on 32 bit pointers.
+
+When you test on the watchOS simulator, you're typically going to be testing with 64-bit pointers,
+so you'll get a 64 bit Int when testing in sim and a 32 bit Int when testing on hardware.
+
+Something as simple as
+
+```swift
+print(String(Int(Date.now.timeIntervalSince1970 * 1000)))
+```
+
+can work fine in the simulator but causes a runtime crash on hardware. Be mindful of your use of Int
+and CGFloat types when deploying code to the Apple Watch.
+
+Here's the output of Int.max on each platform:
+
+| Simulator |  Hardware (oh no!)  |
+|:---------:|:-------------------:|
+| ![64 bit pointers on Apple Watch simulator](/gfx/pointers/64bit.png) | ![32 bit pointers on Apple Watch hardware](/gfx/pointers/32bit.png) |
+
diff --git a/site/gfx/pointers/32bit.png b/site/gfx/pointers/32bit.png
diff --git a/site/gfx/pointers/64bit.png b/site/gfx/pointers/64bit.png