On 10/29/2026 10:23 AM, Fredrik Noring wrote: > Hi Philippe, Maciej, > > [ Maciej, a post [*] from you in 2021 is referenced in the following. ] > > On 28 October 2026, Philippe Mathieu-Daudé wrote: >> There is no libc for the R5900, so its tests can not run in user >> mode [*]. >
I think that Philippe meant "there is no *prebuilt* libc for the r5900". > Both Glibc and Musl are available for the R5900.[1][2] In fact, we also > compile Gentoo for it. I believe the -mfix-r5900 option is used for the > official Gentoo MIPS downloads.[3] > If precompiled glibc or musl with companion toolchain are available from a .tar, yes it could be used. > As for QEMU, I maintain my own fork with R5900 user mode support since > 2020, based on QEMU v5.2, as well as a corresponding Gentoo package,[4][5] > because later versions of QEMU became unfixable and unusable for R5900 > user mode emulation. > > A proper QEMU R5900 user mode must emulate the FPU like the Linux kernel > does, which is why QEMU 5.2 remains the latest usable version of QEMU for > the R5900. > > It’s worth mentioning that there are discussions on introducing additional > FPU modes for the R5900 and Linux, which would allow use of FPU hardware, > despite its noncompliance with IEEE 754.[6][7] > >> [*] >> https://lore.kernel.org/qemu-devel/[email protected]/ >> >> Inspired-by: Maciej W. Rozycki <[email protected]> > > Fredrik > > [1] https://github.com/frno7/gentoo-mipsr5900el > [2] > https://github.com/frno7/gentoo-mipsr5900el/blob/d84d04b2fd9d47d5cce9c1c0884026cc37d008cf/scripts/install-crossdev#L16-L17 > [3] https://www.gentoo.org/downloads/mips/ > [4] https://github.com/frno7/qemu > [5] > https://github.com/frno7/gentoo.overlay/tree/main/app-emulation/qemu-mipsr5900el > [6] https://github.com/frno7/linux/wiki/R5900-floating-point-unit-(FPU) > [7] https://github.com/frno7/linux/issues/3
