Change vm_resize_heap into vm_grow_heap

Makes intention more explicit. Safer for concurrent malloc.

api/syscalls.json

@@ -111,7 +111,7 @@
         "description": "Report the current heap size in bytes."
       },
       {
-        "name": "vm_resize_heap",
+        "name": "vm_grow_heap",
         "args": [
           [
             "u64",
@@ -124,7 +124,7 @@
         ],
         "permission": "default_allowed",
         "const_idx": 17,
-        "description": "Resize the heap to a new size given in bytes. This is similar to the `brk()` system call on POSIX systems. Note that the heap may be resized to a size larger than requested. The heap size is guaranteed to be a multiple of 8 bytes. Returns the new heap size in bytes if successful, or `UINT64_MAX` on failure."
+        "description": "Grow the heap to a new size given in bytes. This is similar to the `brk()` system call on POSIX systems. Note that the heap may be resized to a size larger than requested. The heap size is guaranteed to be a multiple of 8 bytes. If the requested size is smaller than the current heap size, this is a no-op. Returns the new heap size in bytes."
       }
     ],
     "constants": []

doc/syscalls.md

@@ -58,15 +58,15 @@ u64 vm_heap_size()
 
 Report the current heap size in bytes.
 
-## vm_resize_heap
+## vm_grow_heap
 
 ```
-u64 vm_resize_heap(u64 num_bytes)
+u64 vm_grow_heap(u64 num_bytes)
 ```
 
 **Returns:** `u64 new_size`
 
-Resize the heap to a new size given in bytes. This is similar to the `brk()` system call on POSIX systems. Note that the heap may be resized to a size larger than requested. The heap size is guaranteed to be a multiple of 8 bytes. Returns the new heap size in bytes if successful, or `UINT64_MAX` on failure.
+Grow the heap to a new size given in bytes. This is similar to the `brk()` system call on POSIX systems. Note that the heap may be resized to a size larger than requested. The heap size is guaranteed to be a multiple of 8 bytes. If the requested size is smaller than the current heap size, this is a no-op. Returns the new heap size in bytes.
 
 # io
 

ncc/include/uvm/syscalls.h

@@ -25,9 +25,9 @@
 // Report the current heap size in bytes.
 #define vm_heap_size() asm () -> u64 { syscall vm_heap_size; }
 
-// u64 vm_resize_heap(u64 num_bytes)
-// Resize the heap to a new size given in bytes. This is similar to the `brk()` system call on POSIX systems. Note that the heap may be resized to a size larger than requested. The heap size is guaranteed to be a multiple of 8 bytes. Returns the new heap size in bytes if successful, or `UINT64_MAX` on failure.
-#define vm_resize_heap(__num_bytes) asm (__num_bytes) -> u64 { syscall vm_resize_heap; }
+// u64 vm_grow_heap(u64 num_bytes)
+// Grow the heap to a new size given in bytes. This is similar to the `brk()` system call on POSIX systems. Note that the heap may be resized to a size larger than requested. The heap size is guaranteed to be a multiple of 8 bytes. If the requested size is smaller than the current heap size, this is a no-op. Returns the new heap size in bytes.
+#define vm_grow_heap(__num_bytes) asm (__num_bytes) -> u64 { syscall vm_grow_heap; }
 
 // void print_i64(i64 val)
 // Print an i64 value to standard output.

vm/src/sys/constants.rs

@@ -23,7 +23,7 @@ pub const WINDOW_ON_MOUSEUP: u16 = 13;
 pub const VM_HEAP_SIZE: u16 = 14;
 pub const WINDOW_ON_KEYUP: u16 = 15;
 pub const MEMSET32: u16 = 16;
-pub const VM_RESIZE_HEAP: u16 = 17;
+pub const VM_GROW_HEAP: u16 = 17;
 pub const AUDIO_OPEN_OUTPUT: u16 = 18;
 pub const WINDOW_ON_TEXTINPUT: u16 = 19;
 pub const PRINT_F32: u16 = 20;
@@ -61,7 +61,7 @@ pub const SYSCALL_DESCS: [Option<SysCallDesc>; SYSCALL_TBL_LEN] = [
     Some(SysCallDesc { name: "vm_heap_size", const_idx: 14, argc: 0, has_ret: true }),
     Some(SysCallDesc { name: "window_on_keyup", const_idx: 15, argc: 2, has_ret: false }),
     Some(SysCallDesc { name: "memset32", const_idx: 16, argc: 3, has_ret: false }),
-    Some(SysCallDesc { name: "vm_resize_heap", const_idx: 17, argc: 1, has_ret: true }),
+    Some(SysCallDesc { name: "vm_grow_heap", const_idx: 17, argc: 1, has_ret: true }),
     Some(SysCallDesc { name: "audio_open_output", const_idx: 18, argc: 4, has_ret: true }),
     Some(SysCallDesc { name: "window_on_textinput", const_idx: 19, argc: 2, has_ret: false }),
     Some(SysCallDesc { name: "print_f32", const_idx: 20, argc: 1, has_ret: false }),

vm/src/sys/mod.rs

@@ -98,13 +98,12 @@ pub fn get_syscall(const_idx: u16) -> SysCallFn
     match const_idx {
         // Core VM syscalls
         VM_HEAP_SIZE => SysCallFn::Fn0_1(vm_heap_size),
-        VM_RESIZE_HEAP => SysCallFn::Fn1_1(vm_resize_heap),
+        VM_GROW_HEAP => SysCallFn::Fn1_1(vm_grow_heap),
         MEMSET => SysCallFn::Fn3_0(memset),
         MEMSET32 => SysCallFn::Fn3_0(memset32),
         MEMCPY => SysCallFn::Fn3_0(memcpy),
         MEMCMP => SysCallFn::Fn3_1(memcmp),
 
-
         //thread_id
         //thread_sleep
         //thread_spawn
@@ -140,15 +139,12 @@ fn vm_heap_size(thread: &mut Thread) -> Value
     //Value::from(vm.heap_size())
 }
 
-fn vm_resize_heap(thread: &mut Thread, num_bytes: Value) -> Value
+fn vm_grow_heap(thread: &mut Thread, num_bytes: Value) -> Value
 {
-    todo!();
-
-    /*
+    let mut vm = thread.vm.lock().unwrap();
     let num_bytes = num_bytes.as_usize();
-    let new_size = vm.resize_heap(num_bytes);
+    let new_size = vm.grow_heap(num_bytes);
     Value::from(new_size)
-    */
 }
 
 fn thread_id(thread: &mut Thread) -> Value

vm/src/vm.rs

@@ -1670,13 +1670,13 @@ impl VM
         vm
     }
 
-    /*
-    /// Resize the heap to a new size in bytes
-    pub fn resize_heap(&mut self, num_bytes: usize) -> usize
+    /// Grow the heap to a new size in bytes
+    pub fn grow_heap(&mut self, num_bytes: usize) -> usize
     {
-        self.heap.resize(num_bytes)
+        todo!();
+
+        //self.heap.resize(num_bytes)
     }
-    */
 
     // Create a new thread
     pub fn new_thread(vm: &Arc<Mutex<VM>>, fun: Value, args: Vec<Value>) -> u64