On ARM Cortex CPUs with the SIMD "neon" extension, you can do a bunch of complex loads and stores in a single instruction, like so:
vld4.u8 {d0,d1,d2,d3}, [r0@128]
where "@128" means 128-bit aligned. But the iPhone (iOS) SDK uses gas, the gnu assembler. gas treats '@' as a comment character, so the gas syntax uses a colon instead. Or at least it should. The version of gas distributed in the latest 4.3 SDK is broken, so you can't specify an alignment at all. You'll get an error like:
']' expected -- `vld4.u8 {d0,d1,d2,d3},[r3:64]
This is bad because aligned transfers are faster.
The ARM assembler is located in '/Developer/Platforms/iPhoneOS.platform/Developer/usr/libexec/gcc/darwin/arm'. This is what needs to be fixed.