“v0”:
scanon$ cat bar.c
int foo(void) {
__asm__("":::"q0");
return 0;
}
scanon$ xcrun -sdk iphoneos clang bar.c -arch arm64 -c
bar.c:2:16: error: unknown register name 'q0' in asm
__asm__("":::"q0");
^
1 error generated.
scanon$ cat foo.c
int foo(void) {
__asm__("":::"v0");
return 0;
}
scanon$ xcrun -sdk iphoneos clang foo.c -arch arm64 -c
scanon$
arm64 is a new ISA. The actual NEON instructions and register layout are entirely new. You will need to re-write or adapt assembly code for the new architecture.