Merge pull request #262 from corwinkuiper/allocator-trait

implement allocator api so we can allocate to (ew/iw)ram

agb/examples/allocation.rs

@@ -1,5 +1,6 @@
 #![no_std]
 #![no_main]
+#![feature(allocator_api)]
 
 extern crate alloc;
 
@@ -8,7 +9,11 @@ use alloc::boxed::Box;
 #[agb::entry]
 fn main(_gba: agb::Gba) -> ! {
     loop {
+        let a = Box::new_in(1, agb::EWRAM_ALLOC);
         let b = Box::new(1);
-        agb::println!("dynamic allocation made to {:?}", &*b as *const _);
+        let c = Box::new_in(3, agb::IWRAM_ALLOC);
+        agb::println!("ewram allocation made to {:?}", &*a as *const _);
+        agb::println!("global allocation made to {:?}", &*b as *const _);
+        agb::println!("iwram allocation made to {:?}", &*c as *const _);
     }
 }

agb/gba.ld

@@ -65,6 +65,7 @@ SECTIONS {
     .bss : {
         *(.bss .bss.*);
         . = ALIGN(4);
+        __iwram_end = ABSOLUTE(.);
     } > iwram
 
     __iwram_rom_length_bytes = __iwram_data_end - __iwram_data_start;

agb/gba_mb.ld

@@ -63,6 +63,7 @@ SECTIONS {
     .bss : {
         *(.bss .bss.*);
         . = ALIGN(4);
+        __iwram_end = ABSOLUTE(.);
     } > iwram
 
     __iwram_rom_length_bytes = __iwram_data_end - __iwram_data_start;

agb/src/agb_alloc/block_allocator.rs

@@ -3,7 +3,7 @@
 //! the linked list in order of pointer. Blocks are then merged after every
 //! free.
 
-use core::alloc::{GlobalAlloc, Layout};
+use core::alloc::{Allocator, GlobalAlloc, Layout};
 
 use core::cell::RefCell;
 use core::convert::TryInto;
@@ -43,13 +43,13 @@ struct BlockAllocatorState {
     first_free_block: Option<SendNonNull<Block>>,
 }
 
-pub(crate) struct BlockAllocator {
+pub struct BlockAllocator {
     inner_allocator: BumpAllocator,
     state: Mutex<RefCell<BlockAllocatorState>>,
 }
 
 impl BlockAllocator {
-    pub const unsafe fn new(start: StartEnd) -> Self {
+    pub(crate) const unsafe fn new(start: StartEnd) -> Self {
         Self {
             inner_allocator: BumpAllocator::new(start),
             state: Mutex::new(RefCell::new(BlockAllocatorState {
@@ -216,3 +216,21 @@ unsafe impl GlobalAlloc for BlockAllocator {
         self.dealloc(ptr, layout);
     }
 }
+
+unsafe impl Allocator for BlockAllocator {
+    fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, core::alloc::AllocError> {
+        match unsafe { self.alloc(layout) } {
+            None => Err(core::alloc::AllocError),
+            Some(p) => Ok(unsafe {
+                NonNull::new_unchecked(core::ptr::slice_from_raw_parts_mut(
+                    p.as_ptr(),
+                    layout.size(),
+                ))
+            }),
+        }
+    }
+
+    unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
+        self.dealloc(ptr.as_ptr(), layout);
+    }
+}

agb/src/agb_alloc/mod.rs

@@ -33,6 +33,7 @@ impl<T> DerefMut for SendNonNull<T> {
 }
 
 const EWRAM_END: usize = 0x0204_0000;
+const IWRAM_END: usize = 0x0300_8000;
 
 #[global_allocator]
 static GLOBAL_ALLOC: BlockAllocator = unsafe {
@@ -42,8 +43,59 @@ static GLOBAL_ALLOC: BlockAllocator = unsafe {
     })
 };
 
+/// This is the allocator for the External Working Ram. This is currently
+/// equivalent to the Global Allocator (where things are allocated if no allocator is provided). This implements the allocator trait, so
+/// is meant to be used in specifying where certain structures should be
+/// allocated.
+///
+/// ```rust,no_run
+/// #![feature(allocator_api)]
+/// # #![no_std]
+/// # #![no_main]
+/// # use agb::EWRAM_ALLOC;
+/// # extern crate alloc;
+/// # use alloc::vec::Vec;
+/// # fn foo(gba: &mut agb::Gba) {
+/// let mut v = Vec::new_in(EWRAM_ALLOC);
+/// v.push("hello, world");
+/// assert!(
+///     (0x0200_0000..0x0204_0000).contains(&(v.as_ptr() as usize)),
+///     "the address of the vector is inside ewram"
+/// );
+/// # }
+/// ```
+pub static EWRAM_ALLOC: &BlockAllocator = &GLOBAL_ALLOC;
+
+/// This is the allocator for the Internal Working Ram. This implements the
+/// allocator trait, so is meant to be used in specifying where certain
+/// structures should be allocated.
+///
+/// ```rust,no_run
+/// #![feature(allocator_api)]
+/// # #![no_std]
+/// # #![no_main]
+/// # use agb::IWRAM_ALLOC;
+/// # extern crate alloc;
+/// # use alloc::vec::Vec;
+/// # fn foo(gba: &mut agb::Gba) {
+/// let mut v = Vec::new_in(IWRAM_ALLOC);
+/// v.push("hello, world");
+/// assert!(
+///     (0x0300_0000..0x0300_8000).contains(&(v.as_ptr() as usize)),
+///     "the address of the vector is inside iwram"
+/// );
+/// # }
+/// ```
+pub static IWRAM_ALLOC: &BlockAllocator = &__IWRAM_ALLOC;
+static __IWRAM_ALLOC: BlockAllocator = unsafe {
+    BlockAllocator::new(StartEnd {
+        start: iwram_data_end,
+        end: || IWRAM_END,
+    })
+};
+
 #[cfg(any(test, feature = "testing"))]
-pub unsafe fn number_of_blocks() -> u32 {
+pub(crate) unsafe fn number_of_blocks() -> u32 {
     GLOBAL_ALLOC.number_of_blocks()
 }
 
@@ -56,6 +108,16 @@ fn alloc_error(layout: Layout) -> ! {
     );
 }
 
+fn iwram_data_end() -> usize {
+    extern "C" {
+        static __iwram_end: usize;
+    }
+
+    // TODO: This seems completely wrong, but without the &, rust generates
+    // a double dereference :/. Maybe a bug in nightly?
+    (unsafe { &__iwram_end }) as *const _ as usize
+}
+
 fn data_end() -> usize {
     extern "C" {
         static __ewram_data_end: usize;
@@ -150,4 +212,28 @@ mod test {
             "data end should be smaller than 0x0203_0000"
         );
     }
+
+    #[test_case]
+    fn should_return_data_end_somewhere_in_iwram(_gba: &mut crate::Gba) {
+        let data_end = iwram_data_end();
+
+        assert!(
+            (0x0300_0000..0x0300_8000).contains(&data_end),
+            "iwram data end should be in iwram, instead was {}",
+            data_end
+        );
+        crate::println!("data end was {:#010X}", data_end);
+    }
+
+    #[test_case]
+    fn allocate_to_iwram_works(_gba: &mut crate::Gba) {
+        let a = Box::new_in(1, IWRAM_ALLOC);
+        let p = &*a as *const i32;
+        let addr = p as usize;
+        assert!(
+            (0x0300_0000..0x0300_8000).contains(&addr),
+            "address of allocation should be within iwram, instead at {:?}",
+            p
+        );
+    }
 }

agb/src/lib.rs

@@ -11,6 +11,7 @@
     reexport_test_harness_main = "test_main"
 )]
 #![feature(alloc_error_handler)]
+#![feature(allocator_api)]
 #![warn(clippy::all)]
 #![deny(clippy::must_use_candidate)]
 #![deny(clippy::trivially_copy_pass_by_ref)]
@@ -189,6 +190,8 @@ pub mod syscall;
 /// Interactions with the internal timers
 pub mod timer;
 
+pub use {agb_alloc::EWRAM_ALLOC, agb_alloc::IWRAM_ALLOC};
+
 #[cfg(not(any(test, feature = "testing")))]
 #[panic_handler]
 #[allow(unused_must_use)]

book/games/pong/gba.ld

@@ -65,6 +65,7 @@ SECTIONS {
     .bss : {
         *(.bss .bss.*);
         . = ALIGN(4);
+        __iwram_end = ABSOLUTE(.);
     } > iwram
 
     __iwram_rom_length_bytes = __iwram_data_end - __iwram_data_start;

book/games/pong/gba_mb.ld

@@ -63,6 +63,7 @@ SECTIONS {
     .bss : {
         *(.bss .bss.*);
         . = ALIGN(4);
+        __iwram_end = ABSOLUTE(.);
     } > iwram
 
     __iwram_rom_length_bytes = __iwram_data_end - __iwram_data_start;

examples/hyperspace-roll/gba.ld

@@ -65,6 +65,7 @@ SECTIONS {
     .bss : {
         *(.bss .bss.*);
         . = ALIGN(4);
+        __iwram_end = ABSOLUTE(.);
     } > iwram
 
     __iwram_rom_length_bytes = __iwram_data_end - __iwram_data_start;

examples/hyperspace-roll/gba_mb.ld

@@ -63,6 +63,7 @@ SECTIONS {
     .bss : {
         *(.bss .bss.*);
         . = ALIGN(4);
+        __iwram_end = ABSOLUTE(.);
     } > iwram
 
     __iwram_rom_length_bytes = __iwram_data_end - __iwram_data_start;

examples/the-hat-chooses-the-wizard/gba.ld

@@ -65,6 +65,7 @@ SECTIONS {
     .bss : {
         *(.bss .bss.*);
         . = ALIGN(4);
+        __iwram_end = ABSOLUTE(.);
     } > iwram
 
     __iwram_rom_length_bytes = __iwram_data_end - __iwram_data_start;

examples/the-purple-night/gba.ld

@@ -65,6 +65,7 @@ SECTIONS {
     .bss : {
         *(.bss .bss.*);
         . = ALIGN(4);
+        __iwram_end = ABSOLUTE(.);
     } > iwram
 
     __iwram_rom_length_bytes = __iwram_data_end - __iwram_data_start;

examples/the-purple-night/gba_mb.ld

@@ -63,6 +63,7 @@ SECTIONS {
     .bss : {
         *(.bss .bss.*);
         . = ALIGN(4);
+        __iwram_end = ABSOLUTE(.);
     } > iwram
 
     __iwram_rom_length_bytes = __iwram_data_end - __iwram_data_start;

template/gba.ld

@@ -65,6 +65,7 @@ SECTIONS {
     .bss : {
         *(.bss .bss.*);
         . = ALIGN(4);
+        __iwram_end = ABSOLUTE(.);
     } > iwram
 
     __iwram_rom_length_bytes = __iwram_data_end - __iwram_data_start;

template/gba_mb.ld

@@ -63,6 +63,7 @@ SECTIONS {
     .bss : {
         *(.bss .bss.*);
         . = ALIGN(4);
+        __iwram_end = ABSOLUTE(.);
     } > iwram
 
     __iwram_rom_length_bytes = __iwram_data_end - __iwram_data_start;