diff --git a/makefile b/makefile
index 73efef11ca..791fa4d765 100755
--- a/makefile
+++ b/makefile
@@ -81,13 +81,13 @@ endif
 
 ifeq ($(platform),macosx)
 	ifneq ($(filter arm arm64,$(arch)),)
-		x := $(error "please use 'arch=arm' or 'arch=arm64' 'platform=ios' to build for ios-arm")
+		x := $(error "please use ('arch=arm' or 'arch=arm64') 'platform=ios' to build for ios-arm")
 	endif
 endif
 
 ifeq ($(platform),ios)
-	ifeq ($(filter arm i386,$(arch)),)
-		x := $(error "please specify 'arch=i386' or 'arch=arm' with 'platform=ios'")
+	ifeq ($(filter i386 arm arm64,$(arch)),)
+		x := $(error "please specify 'arch=i386', 'arch=arm', or 'arch=arm64' with 'platform=ios'")
 	endif
 endif
 
diff --git a/src/arm.S b/src/arm.S
index 5d33b2cb58..8cf09b1de3 100644
--- a/src/arm.S
+++ b/src/arm.S
@@ -51,7 +51,7 @@ GLOBAL(vmNativeCall):
   mov   w23, w6
 
   // setup stack arguments if necessary
-  sub   sp, sp, w20 // allocate stack
+  sub   sp, sp, w20, uxtw // allocate stack
   mov   x9, sp
 LOCAL(loop):
   cmp   w3, wzr
@@ -79,16 +79,16 @@ LOCAL(populateVFPs):
 
 LOCAL(doCall):
   blr   x19         // call function
-  add   sp, sp, w20 // deallocate stack
+  add   sp, sp, w20, uxtw // deallocate stack
 
   cmp   w23,#FLOAT_TYPE
-  bne   LOCAL(double)
+  b.ne   LOCAL(double)
   fmov  w0,s0
   b     LOCAL(exit)
 
 LOCAL(double):
   cmp   w23,#DOUBLE_TYPE
-  bne   LOCAL(exit)
+  b.ne   LOCAL(exit)
   fmov  x0,d0
 
 LOCAL(exit):
diff --git a/src/avian/arm.h b/src/avian/arm.h
index 9fbc83c474..c0309486a3 100644
--- a/src/avian/arm.h
+++ b/src/avian/arm.h
@@ -34,7 +34,11 @@
 
 #define THREAD_STATE_IP(state) ((state).FIELD(pc))
 #define THREAD_STATE_STACK(state) ((state).FIELD(sp))
+#if (defined __APPLE__) && (defined ARCH_arm64)
+#define THREAD_STATE_THREAD(state) ((state).FIELD(x[19]))
+#else
 #define THREAD_STATE_THREAD(state) ((state).FIELD(r[8]))
+#endif
 #define THREAD_STATE_LINK(state) ((state).FIELD(lr))
 
 #define IP_REGISTER(context) THREAD_STATE_IP(context->uc_mcontext->FIELD(ss))
diff --git a/src/tools/binary-to-object/main.cpp b/src/tools/binary-to-object/main.cpp
index 1636d46dfd..ed984b12f5 100644
--- a/src/tools/binary-to-object/main.cpp
+++ b/src/tools/binary-to-object/main.cpp
@@ -50,20 +50,11 @@ bool writeObject(uint8_t* data,
                  OutputStream* out,
                  const char* startName,
                  const char* endName,
-                 const char* format,
-                 const char* architecture,
+                 Platform* platform,
                  unsigned alignment,
                  bool writable,
                  bool executable)
 {
-  Platform* platform = Platform::getPlatform(
-      PlatformInfo(PlatformInfo::formatFromString(format),
-                   PlatformInfo::archFromString(architecture)));
-
-  if (!platform) {
-    fprintf(stderr, "unsupported platform: %s/%s\n", format, architecture);
-    return false;
-  }
 
   SymbolInfo symbols[] = {SymbolInfo(0, startName), SymbolInfo(size, endName)};
 
@@ -113,6 +104,19 @@ int main(int argc, const char** argv)
     }
   }
 
+  const char* format = argv[5];
+  const char* architecture = argv[6];
+
+  Platform* platform = Platform::getPlatform(
+      PlatformInfo(PlatformInfo::formatFromString(format),
+                   PlatformInfo::archFromString(architecture)));
+
+  if (!platform) {
+    fprintf(stderr, "unsupported platform: %s/%s\n", format, architecture);
+    return 1;
+  }
+
+
   uint8_t* data = 0;
   unsigned size;
   int fd = open(argv[1], O_RDONLY);
@@ -148,8 +152,7 @@ int main(int argc, const char** argv)
                             &out,
                             argv[3],
                             argv[4],
-                            argv[5],
-                            argv[6],
+                            platform,
                             alignment,
                             writable,
                             executable);
diff --git a/src/tools/object-writer/mach-o.cpp b/src/tools/object-writer/mach-o.cpp
index 524407a381..c35a7058ac 100644
--- a/src/tools/object-writer/mach-o.cpp
+++ b/src/tools/object-writer/mach-o.cpp
@@ -33,10 +33,12 @@
 #define CPU_TYPE_I386 7
 #define CPU_TYPE_X86_64 (CPU_TYPE_I386 | CPU_ARCH_ABI64)
 #define CPU_TYPE_ARM 12
+#define CPU_TYPE_ARM64 (CPU_TYPE_ARM | CPU_ARCH_ABI64)
 
 #define CPU_SUBTYPE_I386_ALL 3
 #define CPU_SUBTYPE_X86_64_ALL CPU_SUBTYPE_I386_ALL
 #define CPU_SUBTYPE_ARM_V7 9
+#define CPU_SUBTYPE_ARM_V8 13
 
 namespace {
 
@@ -157,6 +159,10 @@ class MachOPlatform : public Platform {
       cpuType = CPU_TYPE_ARM;
       cpuSubType = CPU_SUBTYPE_ARM_V7;
       break;
+    case PlatformInfo::Arm64:
+      cpuType = CPU_TYPE_ARM64;
+      cpuSubType = CPU_SUBTYPE_ARM_V8;
+      break;
     default:
       // should never happen (see MachOPlatform declarations at bottom)
       fprintf(stderr, "unsupported architecture: %d\n", info.arch);
@@ -280,6 +286,7 @@ class MachOPlatform : public Platform {
 
 MachOPlatform<uint32_t> darwinx86Platform(PlatformInfo::x86);
 MachOPlatform<uint32_t> darwinArmPlatform(PlatformInfo::Arm);
+MachOPlatform<uint64_t> darwinArm64Platform(PlatformInfo::Arm64);
 MachOPlatform<uint64_t> darwinx86_64Platform(PlatformInfo::x86_64);
 
 }  // namespace