On Fri Jul 18 22:28:12 EDT 2014, cinap_len...@felloff.net wrote: > so, we say r14 and r15 arent really special for user programs. and its > just a c compiler implementation detail that it doesnt allocate these > registers, but assembly code can freely use them for scratch space > or whatever. extern register will not work in userspace c programs > because syscalls will trash these registers. > > makes any sense?
certainly. speaking for myself, the model that r14 and r15 are off limits for esoteric reasons is preferrable, given the quite limited maximum benefit, to the complications of sneaking by the limitation. obviously, the mips port avoided this by never needing >28 live registers at once. - erik
