diff --git a/src/arm.rs b/src/arm.rs
index 227ab05..b72ff97 100644
--- a/src/arm.rs
+++ b/src/arm.rs
@@ -61,14 +61,16 @@ pub unsafe fn __aeabi_ldivmod() {
 
 // FIXME: The `*4` and `*8` variants should be defined as aliases.
 
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memcpy(dest: *mut u8, src: *const u8, n: usize) {
     mem::memcpy(dest, src, n);
 }
 
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memcpy4(dest: *mut u8, src: *const u8, mut n: usize) {
     let mut dest = dest as *mut u32;
     let mut src = src as *mut u32;
@@ -83,39 +85,45 @@ pub unsafe extern "aapcs" fn __aeabi_memcpy4(dest: *mut u8, src: *const u8, mut
     __aeabi_memcpy(dest as *mut u8, src as *const u8, n);
 }
 
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memcpy8(dest: *mut u8, src: *const u8, n: usize) {
     __aeabi_memcpy4(dest, src, n);
 }
 
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memmove(dest: *mut u8, src: *const u8, n: usize) {
     mem::memmove(dest, src, n);
 }
 
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memmove4(dest: *mut u8, src: *const u8, n: usize) {
     __aeabi_memmove(dest, src, n);
 }
 
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memmove8(dest: *mut u8, src: *const u8, n: usize) {
     __aeabi_memmove(dest, src, n);
 }
 
-// Note the different argument order
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memset(dest: *mut u8, n: usize, c: i32) {
+    // Note the different argument order
     mem::memset(dest, c, n);
 }
 
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memset4(dest: *mut u8, mut n: usize, c: i32) {
     let mut dest = dest as *mut u32;
 
@@ -131,26 +139,30 @@ pub unsafe extern "aapcs" fn __aeabi_memset4(dest: *mut u8, mut n: usize, c: i32
     __aeabi_memset(dest as *mut u8, n, byte as i32);
 }
 
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memset8(dest: *mut u8, n: usize, c: i32) {
     __aeabi_memset4(dest, n, c);
 }
 
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memclr(dest: *mut u8, n: usize) {
     __aeabi_memset(dest, n, 0);
 }
 
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memclr4(dest: *mut u8, n: usize) {
     __aeabi_memset4(dest, n, 0);
 }
 
+#[cfg(not(target_os = "ios"))]
 #[cfg_attr(not(feature = "mangled-names"), no_mangle)]
-#[linkage = "weak"]
+#[cfg_attr(thumb, linkage = "weak")]
 pub unsafe extern "aapcs" fn __aeabi_memclr8(dest: *mut u8, n: usize) {
     __aeabi_memset4(dest, n, 0);
 }