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Floating point emulation support for RT-AC88U

Discussion in 'Asuswrt-Merlin' started by Anson, Aug 12, 2017.

  1. Anson

    Anson New Around Here

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    Hi,

    I am getting "Illegal Instruction" for some go executable and google suggested it may related to no FPU or FPU emulation is not enabled in kernel.

    FastFPE math emulation (EXPERIMENTAL) looks enabled by default, I am not sure why it's not working. So I am trying to re-compile kernal with "NWFPE math emulation" or VPF-format floating points maths support. Unfortunately kernel compile failed with below error. Any idea?


    ~/asuswrt-merlin/release/src-rt-7.14.114.x/src/$ make kernel
    :
    :
    :


    make[2]: Entering directory '/home/thx/asuswrt-merlin/release/src/router/compressed'
    arm-brcm-linux-uclibcgnueabi-objcopy -O binary -R .note -R .note.gnu.build-id -R .comment -S /home/thx/asuswrt-merlin/release/src-rt-7.14.114.x/src/linux/linux-2.6/vmlinux piggy
    /home/thx/asuswrt-merlin/release/src-rt-7.14.114.x/src/ctools/lzma_4k e piggy piggz
    arm-brcm-linux-uclibcgnueabi-ld -no-warn-mismatch -T piggy.lds -r -o piggy.o -b binary piggz -b elf32-littlearm
    arm-brcm-linux-uclibcgnueabi-ld -static --gc-sections -no-warn-mismatch -T vmlinux.lds -o vmlinux bootarm.o aisdram_ca9.o siutils.o hndarm_ca9.o pcieinit_ca9.o sbutils.o aiutils.o nicpci.o pcie_core.o load.o hndchipc.o hndpmu.o min_osl.o bcmutils.o bcmstdlib.o sromstubs.o nvramstubs.o -L /home/thx/asuswrt-merlin/release/src-rt-6.x.4708/toolchains/hndtools-arm-linux-2.6.36-uclibc-4.5.3/bin/../lib/gcc/arm-brcm-linux-uclibcgnueabi/4.5.3 -lgcc piggy.o
    hndpmu.o: In function `si_pmu_chipcontrol':
    /home/thx/asuswrt-merlin/release/src-rt-7.14.114.x/src/shared/hndpmu.c:150: undefined reference to `si_pmu_corereg'

    Thank you.
     
  2. Vexira

    Vexira Very Senior Member

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    im qurios what is the purpose of Floating point emulation support, and what are you trying to achieve by enabling it?
     
    Last edited: Aug 13, 2017
  3. Anson

    Anson New Around Here

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    Well, at lease I can get nodeJS running ...

    [email protected]:/tmp/home/root# node
    Illegal instruction
     
  4. Vexira

    Vexira Very Senior Member

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    I mean I was asking how does it affect the router if you can get it working?
     
  5. Anson

    Anson New Around Here

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    I was thinking that can fix "Illegal instruction" problem. Or am I looking at a wrong direction?
     
  6. sfx2000

    sfx2000 Part of the Furniture

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    Look at Entware - if I recall, they have NodeJS in their tree...

    Alt approach would be a Pi2/Pi3 - nodejs is fully supported there, and more RAM available to boot - NodeJS can be very resource intense depending on the code running...
     
  7. Anson

    Anson New Around Here

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    Thanks, I am using the node come with Entware, but not sure why I am getting Illegal instruction, if it's not related to FPU emulation.
     
  8. ResumeNothing

    ResumeNothing New Around Here

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    I'm getting the same error on RT-AC68P. I think you're correct about it being because there's no FPU emulation:

    https://github.com/nodejs/node/issues/7343

    Depending on your needs, you might be able to get by by install the node_legacy package instead. I was able to get node to work on my router with that.
     
  9. sfx2000

    sfx2000 Part of the Furniture

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    when getting into NPM - a lot of the packages are armhf - thanks to the Pi community...

    The RT-AC series with Cortex-A9 - they're armel...

    gcc options - look at ARMv7-a, -mfloat-abi=soft which should work ok... might try softfp perhaps...
     
  10. Anson

    Anson New Around Here

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    Thanks, bt isn't Cortex-A9 has a FPU ? Or it's removed on art-AC series?
     
  11. sfx2000

    sfx2000 Part of the Furniture

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    Cortex-A9 - it's optional... and the Broadcom SoC has not implemented it.
     
  12. Vexira

    Vexira Very Senior Member

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