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Altera_Forum's avatar
Altera_Forum
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12 years ago

"HW_MUL_SUPPORT" in Nios2-Linux with MMU supported distribution

All,

Can anyone please explain how enabling/disabling "hw_mul_support" in Nios2-Linux with MMU supported distribution works? I'm using embed multiplier supported SOPC system. When I tested multiplication operation using this system with enabling and disabling HW_MUL_SUPPORT, I did not observe any difference between them.

Enabling this support in make menuconfig enables "-mno-hw-mul" flag at compile time. Does it create different multiplication instruction at compile time for multiplication operation? I want to trace the assembly instructions that are used for both enabled/disabled support. Can anyone help me?

Thanks in advance!

Regards,

Harshil

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    12 years ago

    --- Quote Start ---

    Enabling this support in make menuconfig enables "-mno-hw-mul" flag at compile time. Does it create different multiplication instruction at compile time for multiplication operation?

    --- Quote End ---

    Yes. I think there is a separate setting for kernel and apps though. If you are compiling your app separately from uClinux-dist, you'll need to set the flag yourself.

    --- Quote Start ---

    I want to trace the assembly instructions that are used for both enabled/disabled support. Can anyone help me?

    --- Quote End ---

    Look at the disassembly using nios2-linux-gnu-objdump (man objdump).