Loongson-3a specific instructions are used in this program, so I use "-march=loongson3a -mabi=32" to compile it. The configure script will use -march to probe whether these instructions are supported, and I don't want to break this behavior. P.S: Loongson-3a is mips64 compatible, it has the same behavior to use FPRs as mips64. On Thu, Dec 1, 2011 at 12:57 AM, Ian Lance Taylor <iant@xxxxxxxxxx> wrote: > Heiher <admin@xxxxxxxxxxx> writes: > >> I want to use ICT Loongson 3A extension SIMD instructions in o32 ABI >> program. The march loongson3a is based on mips64. -mfp32 don't work... > > I guess I don't know what it means to use -mips64 with -mabi=32. I'm > not surprised that it doesn't work. I don't even think this is is a > bug. You explained why you want to use -mips64, but why do you want to > use -mabi=32? Why not just recompile the program? > > If you can't recompile the program, then as far as I can see you are > going to have to write some sort of stubs to call between your o32 code > and your mips64 code. > > Ian > >> On Wed, Nov 30, 2011 at 2:42 PM, Ian Lance Taylor <iant@xxxxxxxxxx> wrote: >>> Heiher <admin@xxxxxxxxxxx> writes: >>> >>>> The o32 abi programs could only use even-numbered floating-point >>>> registers by appointment. The GCC generate assembly source code using >>>> odd-numbered floating-point register when I -march=mips64 and >>>> -mabi=32. Every double floating-point instructions will use 32-bit >>>> even/odd-numbered paired 64-bit fpr when 0 = bit FR in Status >>>> register. However kernel set bit FR to a thread at loading ELF for N32 >>>> or 64 only. In other words, o32 abi process can't use odd-numbered >>>> fpr. >>>> >>>> How ought I to act? Thanks! >>> >>> I'm not sure it makes sense to use -march=mips64 -mabi=32. Why do you >>> want to do that? >>> >>> You could try using the -mfp32 option but I don't know whether it will >>> help. >>> >>> Ian -- Best regards! Heiher
