On Fri, May 3, 2019 at 3:11 PM Maciej W. Rozycki <ma...@wdc.com> wrote: > Hmm, I've been thinking a little bit about this hybrid mode and I have > one question: how do we pass the IEEE rounding mode setting between `fcsr' > and softfp where we have `-march=rv32imafc -mabi=ilp32' and > `-march=rv32imac -mabi=ilp32' object modules interlinked?
If you look at libgcc/config/riscv/sfp-machine.h you will see definitions of FP_INIT_ROUNDMODE and FP_HANDLE_EXCEPTIONS for reading rounding mode from the fcsr before soft-float FP operations, and storing the exception flags back into fcsr after soft-float FP operations, if FP regs exist.. Whether this actually works, I don't know, I haven't tested it. I think in practice people using soft-float libraries are probably not relying on rounding modes and exception flags much if at all, so this is unlikely to be a problem. If someone does find a problem, I will worry about how to fix it then. Jim
