From 55d07b6cb0460fae63c0cfb6730dba462ba2c560 Mon Sep 17 00:00:00 2001
From: Nidin Vinayakan <01@01alchemist.com>
Date: Thu, 28 Feb 2019 15:21:57 +0100
Subject: [PATCH 1/2] Atomic memory allocator

Atomic allocator for shared memory
---
 std/assembly/allocator/atomic.ts | 49 ++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 std/assembly/allocator/atomic.ts

diff --git a/std/assembly/allocator/atomic.ts b/std/assembly/allocator/atomic.ts
new file mode 100644
index 0000000000..a218aaf809
--- /dev/null
+++ b/std/assembly/allocator/atomic.ts
@@ -0,0 +1,49 @@
+import { AL_MASK, MAX_SIZE_32 } from "../internal/allocator";
+
+var SATRT_OFFSET: usize = (HEAP_BASE + AL_MASK) & ~AL_MASK;
+var OFFSET_PTR: usize = SATRT_OFFSET;
+var TOP = (HEAP_BASE + 8 + AL_MASK) & ~AL_MASK;
+store<usize>(OFFSET_PTR, TOP);
+
+@global export function __allocator_get_offset(): usize {
+  return Atomic.load<usize>(OFFSET_PTR);
+}
+
+@global export function __allocator_set_offset(oldOffset: usize, newOffset: usize): usize {
+  return Atomic.cmpxchg<usize>(OFFSET_PTR, oldOffset, newOffset);
+}
+
+@global export function __memory_allocate(size: usize): usize {
+  if (size) {
+    if (size > MAX_SIZE_32) unreachable();
+    let currentOffset: usize;
+    let top: usize;
+    do {
+      currentOffset = __allocator_get_offset();
+      top = (currentOffset + size + AL_MASK) & ~AL_MASK;
+      let pagesBefore = memory.size();
+      if (top > (<usize>pagesBefore) << 16) {
+        let pagesNeeded = ((top - currentOffset + 0xffff) & ~0xffff) >>> 16;
+        let pagesWanted = max(pagesBefore, pagesNeeded); // double memory
+        if (memory.grow(pagesWanted) < 0) {
+          if (memory.grow(pagesNeeded) < 0) {
+            unreachable(); // out of memory
+          }
+        }
+      }
+    } while (
+      Atomic.cmpxchg<usize>(OFFSET_PTR, currentOffset, top) != currentOffset
+    );
+
+    return currentOffset;
+  }
+  return 0;
+}
+
+@global export function __memory_free(ptr: usize): void {
+ //TODO: Not implemented
+}
+
+@global export function __memory_reset(): void {
+  Atomic.store<usize>(OFFSET_PTR, SATRT_OFFSET);
+}

From 182c9b94d5d053b092239b044be9afe2ae27816c Mon Sep 17 00:00:00 2001
From: Nidin Vinayakan <nidinthb@gmail.com>
Date: Thu, 28 Feb 2019 15:30:58 +0100
Subject: [PATCH 2/2] Update atomic.ts

---
 std/assembly/allocator/atomic.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/std/assembly/allocator/atomic.ts b/std/assembly/allocator/atomic.ts
index a218aaf809..ee9d620e62 100644
--- a/std/assembly/allocator/atomic.ts
+++ b/std/assembly/allocator/atomic.ts
@@ -6,11 +6,11 @@ var TOP = (HEAP_BASE + 8 + AL_MASK) & ~AL_MASK;
 store<usize>(OFFSET_PTR, TOP);
 
 @global export function __allocator_get_offset(): usize {
-  return Atomic.load<usize>(OFFSET_PTR);
+  return atomic.load<usize>(OFFSET_PTR);
 }
 
 @global export function __allocator_set_offset(oldOffset: usize, newOffset: usize): usize {
-  return Atomic.cmpxchg<usize>(OFFSET_PTR, oldOffset, newOffset);
+  return atomic.cmpxchg<usize>(OFFSET_PTR, oldOffset, newOffset);
 }
 
 @global export function __memory_allocate(size: usize): usize {
@@ -32,7 +32,7 @@ store<usize>(OFFSET_PTR, TOP);
         }
       }
     } while (
-      Atomic.cmpxchg<usize>(OFFSET_PTR, currentOffset, top) != currentOffset
+      atomic.cmpxchg<usize>(OFFSET_PTR, currentOffset, top) != currentOffset
     );
 
     return currentOffset;
@@ -45,5 +45,5 @@ store<usize>(OFFSET_PTR, TOP);
 }
 
 @global export function __memory_reset(): void {
-  Atomic.store<usize>(OFFSET_PTR, SATRT_OFFSET);
+  atomic.store<usize>(OFFSET_PTR, SATRT_OFFSET);
 }