From 94d5a710074bc11367e3307da30f94cc9a58b167 Mon Sep 17 00:00:00 2001
From: Gwilym Kuiper <gw@ilym.me>
Date: Mon, 16 Aug 2021 21:14:28 +0100
Subject: [PATCH] Split out bump_allocator

---
 agb/src/agb_alloc/bump_allocator.rs | 86 ++++++++++++++++++++++++++++
 agb/src/agb_alloc/mod.rs            | 87 +----------------------------
 2 files changed, 88 insertions(+), 85 deletions(-)
 create mode 100644 agb/src/agb_alloc/bump_allocator.rs

diff --git a/agb/src/agb_alloc/bump_allocator.rs b/agb/src/agb_alloc/bump_allocator.rs
new file mode 100644
index 00000000..631fa217
--- /dev/null
+++ b/agb/src/agb_alloc/bump_allocator.rs
@@ -0,0 +1,86 @@
+use core::alloc::{GlobalAlloc, Layout};
+
+use crate::interrupt::Mutex;
+
+fn get_data_end() -> usize {
+    extern "C" {
+        static __ewram_data_end: usize;
+    }
+
+    // TODO: This seems completely wrong, but without the &, rust generates
+    // a double dereference :/. Maybe a bug in nightly?
+    (unsafe { &__ewram_data_end }) as *const _ as usize
+}
+
+pub(super) struct BumpAllocator {
+    current_ptr: Mutex<*mut u8>,
+}
+
+impl BumpAllocator {
+    pub const fn new() -> Self {
+        Self {
+            current_ptr: Mutex::new(core::ptr::null_mut()),
+        }
+    }
+}
+
+impl BumpAllocator {
+    fn alloc_safe(&self, layout: Layout) -> *mut u8 {
+        let mut current_ptr = self.current_ptr.lock();
+
+        let ptr = if current_ptr.is_null() {
+            get_data_end()
+        } else {
+            *current_ptr as usize
+        };
+
+        let alignment_bitmask = layout.align() - 1;
+        let fixup = ptr & alignment_bitmask;
+
+        let amount_to_add = layout.align() - fixup;
+
+        let resulting_ptr = ptr + amount_to_add;
+        *current_ptr = (resulting_ptr + layout.size()) as *mut _;
+
+        resulting_ptr as *mut _
+    }
+}
+
+unsafe impl GlobalAlloc for BumpAllocator {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        self.alloc_safe(layout)
+    }
+
+    unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {}
+}
+
+#[alloc_error_handler]
+fn alloc_error(layout: Layout) -> ! {
+    panic!(
+        "Failed to allocate size {} with alignment {}",
+        layout.size(),
+        layout.align()
+    );
+}
+
+#[cfg(test)]
+mod test {
+    use alloc::boxed::Box;
+
+    #[test_case]
+    fn test_box(_gba: &mut crate::Gba) {
+        let first_box = Box::new(1);
+        let second_box = Box::new(2);
+
+        assert!(&*first_box as *const _ < &*second_box as *const _);
+        assert_eq!(*first_box, 1);
+        assert_eq!(*second_box, 2);
+
+        let address = &*first_box as *const _ as usize;
+        assert!(
+            address >= 0x0200_0000 && address < 0x0204_0000,
+            "ewram is located between 0x0200_0000 and 0x0204_0000, address was actually found to be {:#010X}",
+            address
+        );
+    }
+}
diff --git a/agb/src/agb_alloc/mod.rs b/agb/src/agb_alloc/mod.rs
index 88d75c2d..6d26da3f 100644
--- a/agb/src/agb_alloc/mod.rs
+++ b/agb/src/agb_alloc/mod.rs
@@ -1,89 +1,6 @@
-use core::alloc::{GlobalAlloc, Layout};
+mod bump_allocator;
 
-use super::interrupt::Mutex;
-
-fn get_data_end() -> usize {
-    extern "C" {
-        static __ewram_data_end: usize;
-    }
-
-    // TODO: This seems completely wrong, but without the &, rust generates
-    // a double dereference :/. Maybe a bug in nightly?
-    (unsafe { &__ewram_data_end }) as *const _ as usize
-}
-
-struct BumpAllocator {
-    current_ptr: Mutex<*mut u8>,
-}
-
-impl BumpAllocator {
-    pub const fn new() -> Self {
-        Self {
-            current_ptr: Mutex::new(core::ptr::null_mut()),
-        }
-    }
-}
-
-impl BumpAllocator {
-    fn alloc_safe(&self, layout: Layout) -> *mut u8 {
-        let mut current_ptr = self.current_ptr.lock();
-
-        let ptr = if current_ptr.is_null() {
-            get_data_end()
-        } else {
-            *current_ptr as usize
-        };
-
-        let alignment_bitmask = layout.align() - 1;
-        let fixup = ptr & alignment_bitmask;
-
-        let amount_to_add = layout.align() - fixup;
-
-        let resulting_ptr = ptr + amount_to_add;
-        *current_ptr = (resulting_ptr + layout.size()) as *mut _;
-
-        resulting_ptr as *mut _
-    }
-}
-
-unsafe impl GlobalAlloc for BumpAllocator {
-    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        self.alloc_safe(layout)
-    }
-
-    unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {}
-}
-
-#[alloc_error_handler]
-fn alloc_error(layout: Layout) -> ! {
-    panic!(
-        "Failed to allocate size {} with alignment {}",
-        layout.size(),
-        layout.align()
-    );
-}
+use bump_allocator::BumpAllocator;
 
 #[global_allocator]
 static GLOBAL_ALLOC: BumpAllocator = BumpAllocator::new();
-
-#[cfg(test)]
-mod test {
-    use alloc::boxed::Box;
-
-    #[test_case]
-    fn test_box(_gba: &mut crate::Gba) {
-        let first_box = Box::new(1);
-        let second_box = Box::new(2);
-
-        assert!(&*first_box as *const _ < &*second_box as *const _);
-        assert_eq!(*first_box, 1);
-        assert_eq!(*second_box, 2);
-
-        let address = &*first_box as *const _ as usize;
-        assert!(
-            address >= 0x0200_0000 && address < 0x0204_0000,
-            "ewram is located between 0x0200_0000 and 0x0204_0000, address was actually found to be {:#010X}",
-            address
-        );
-    }
-}