On Fri, 14 Oct 2011, Richard Earnshaw wrote: > One way we might address this is to redefine our 128-bit vector types as > structs of low/high Dwords. Each Dword remains a vector (apart from > 64-bit lane types), but the Dword order then matches the ABI > specification correctly. For example, the definition of uint8x16_t becomes > > typedef struct { uint8x8_t _val[2]; } uint8x16_t;
Those types have different ABIs for argument passing and return, so you'd need some magic for special handling of the uint8x16_t type as defined in the header.... > Secondly, all vector loads/stores should really be changed to use > vld1.64 (with {d<n>, d<n+1>} as the register list for 128-bit accesses) > rather than vldm; this then sorts out any issues with unaligned accesses > without changing the memory format. vld1 runs into problems for big-endian of not being able to do core register loads / stores / transfers between core and NEON registers that way, and needing to convert to the other format for argument passing / return. -- Joseph S. Myers jos...@codesourcery.com