Match OSArena (#15)

configure.py

@@ -806,7 +806,7 @@ LIBS = [
             ["Dolphin/os/__start", True],
             "Dolphin/os/OS",
             ["Dolphin/os/OSAlarm", True],
-            "Dolphin/os/OSArena",
+            ["Dolphin/os/OSArena", True],
             ["Dolphin/os/OSAudioSystem", True],
             ["Dolphin/os/OSCache", True],
             "Dolphin/os/OSContext",

include/dolphin/os/OSArena.h

@@ -1,4 +1,13 @@
 #ifndef _DOLPHIN_OSARENA
 #define _DOLPHIN_OSARENA
 
+#include <dolphin/types.h>
+
+void* OSGetArenaHi(void);
+void* OSGetArenaLo(void);
+void OSSetArenaHi(void* addr);
+void OSSetArenaLo(void* addr);
+void* OSAllocFromArenaLo(u32 size, u32 align);
+void* OSAllocFromArenaLo(u32 size, u32 align);
+
 #endif // _DOLPHIN_OSARENA

src/Dolphin/os/OSArena.c

@@ -0,0 +1,39 @@
+#include <dolphin/os/OSArena.h>
+
+#define ROUND(n, a) (((u32)(n) + (a)-1) & ~((a)-1))
+#define TRUNC(n, a) (((u32)(n)) & ~((a)-1))
+
+void* __OSArenaHi;
+void* __OSArenaLo = (void*)-1;
+
+void* OSGetArenaHi(void) { return __OSArenaHi; }
+
+void* OSGetArenaLo(void) { return __OSArenaLo; }
+
+void OSSetArenaHi(void* addr) { __OSArenaHi = addr; }
+
+void OSSetArenaLo(void* addr) { __OSArenaLo = addr; }
+
+void* OSAllocFromArenaLo(u32 size, u32 align) {
+  void* ptr;
+  u8* arenaLo;
+
+  ptr = OSGetArenaLo();
+  arenaLo = ptr = (void*)ROUND(ptr, align);
+  arenaLo += size;
+  arenaLo = (u8*)ROUND(arenaLo, align);
+  OSSetArenaLo(arenaLo);
+  return ptr;
+}
+
+void* OSAllocFromArenaHi(u32 size, u32 align) {
+  void* ptr;
+  u8* arenaHi;
+
+  arenaHi = OSGetArenaHi();
+  arenaHi = (u8*)TRUNC(arenaHi, align);
+  arenaHi -= size;
+  arenaHi = ptr = (void*)TRUNC(arenaHi, align);
+  OSSetArenaHi(arenaHi);
+  return ptr;
+}