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net: gptp: fix src MAC address #13107

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merged 1 commit into from
Feb 7, 2019

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dgloeck
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@dgloeck dgloeck commented Feb 6, 2019

The return value of net_if_get_link_addr points to a struct net_linkaddr
instead of to the raw MAC address. Without this fix the source address
will always end in 06:03 and will most likely be the same for different
boards running the same software.

The return value of net_if_get_link_addr points to a struct net_linkaddr
instead of to the raw MAC address. Without this fix the source address
will always end in 06:03 and will most likely be the same for different
boards running the same software.

Signed-off-by: Daniel Glöckner <[email protected]>
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Codecov Report

Merging #13107 into master will not change coverage.
The diff coverage is n/a.

Impacted file tree graph

@@           Coverage Diff           @@
##           master   #13107   +/-   ##
=======================================
  Coverage   48.62%   48.62%           
=======================================
  Files         313      313           
  Lines       46484    46484           
  Branches    10728    10728           
=======================================
  Hits        22604    22604           
  Misses      19413    19413           
  Partials     4467     4467

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Nice catch!

@jukkar jukkar merged commit 1e676d6 into zephyrproject-rtos:master Feb 7, 2019
npitre pushed a commit to npitre/zephyr that referenced this pull request Oct 31, 2020
The _ldiv5() is an optimized divide-by-5 function that is smaller and
faster than the generic libgcc implementation.

Yet it can be made even smaller and faster with this replacement
implementation based on a reciprocal multiplication plus some tricks.

For example, here's the assembly from the original code on ARM:

_ldiv5:
        ldr     r3, [r0]
        movw    ip, zephyrproject-rtos#52429
        ldr     r1, [r0, zephyrproject-rtos#4]
        movt    ip, 52428
        adds    r3, r3, zephyrproject-rtos#2
        push    {r4, r5, r6, r7, lr}
        mov     lr, #0
        adc     r1, r1, lr
        adds    r2, lr, lr
        umull   r7, r6, ip, r1
        lsr     r6, r6, zephyrproject-rtos#2
        adc     r7, r6, r6
        adds    r2, r2, r2
        adc     r7, r7, r7
        adds    r2, r2, lr
        adc     r7, r7, r6
        subs    r3, r3, r2
        sbc     r7, r1, r7
        lsr     r2, r3, zephyrproject-rtos#3
        orr     r2, r2, r7, lsl zephyrproject-rtos#29
        umull   r2, r1, ip, r2
        lsr     r2, r1, zephyrproject-rtos#2
        lsr     r7, r1, zephyrproject-rtos#31
        lsl     r1, r2, zephyrproject-rtos#3
        adds    r4, lr, r1
        adc     r5, r6, r7
        adds    r2, r1, r1
        adds    r2, r2, r2
        adds    r2, r2, r1
        subs    r2, r3, r2
        umull   r3, r2, ip, r2
        lsr     r2, r2, zephyrproject-rtos#2
        adds    r4, r4, r2
        adc     r5, r5, #0
        strd    r4, [r0]
        pop     {r4, r5, r6, r7, pc}

And here's the resulting assembly with this commit applied:

_ldiv5:
        push    {r4, r5, r6, r7}
        movw    r4, zephyrproject-rtos#13107
        ldr     r6, [r0]
        movt    r4, 13107
        ldr     r1, [r0, zephyrproject-rtos#4]
        mov     r3, #0
        umull   r6, r7, r6, r4
        add     r2, r4, r4, lsl zephyrproject-rtos#1
        umull   r4, r5, r1, r4
        adds    r1, r6, r2
        adc     r2, r7, r2
        adds    ip, r6, r4
        adc     r1, r7, r5
        adds    r2, ip, r2
        adc     r2, r1, r3
        adds    r2, r4, r2
        adc     r3, r5, r3
        strd    r2, [r0]
        pop     {r4, r5, r6, r7}
        bx      lr

So we're down to 20 instructions from 36 initially, with only 2 umull
instructions instead of 3, and slightly smaller stack footprint.

Signed-off-by: Nicolas Pitre <[email protected]>
andrewboie pushed a commit that referenced this pull request Nov 9, 2020
The _ldiv5() is an optimized divide-by-5 function that is smaller and
faster than the generic libgcc implementation.

Yet it can be made even smaller and faster with this replacement
implementation based on a reciprocal multiplication plus some tricks.

For example, here's the assembly from the original code on ARM:

_ldiv5:
        ldr     r3, [r0]
        movw    ip, #52429
        ldr     r1, [r0, #4]
        movt    ip, 52428
        adds    r3, r3, #2
        push    {r4, r5, r6, r7, lr}
        mov     lr, #0
        adc     r1, r1, lr
        adds    r2, lr, lr
        umull   r7, r6, ip, r1
        lsr     r6, r6, #2
        adc     r7, r6, r6
        adds    r2, r2, r2
        adc     r7, r7, r7
        adds    r2, r2, lr
        adc     r7, r7, r6
        subs    r3, r3, r2
        sbc     r7, r1, r7
        lsr     r2, r3, #3
        orr     r2, r2, r7, lsl #29
        umull   r2, r1, ip, r2
        lsr     r2, r1, #2
        lsr     r7, r1, #31
        lsl     r1, r2, #3
        adds    r4, lr, r1
        adc     r5, r6, r7
        adds    r2, r1, r1
        adds    r2, r2, r2
        adds    r2, r2, r1
        subs    r2, r3, r2
        umull   r3, r2, ip, r2
        lsr     r2, r2, #2
        adds    r4, r4, r2
        adc     r5, r5, #0
        strd    r4, [r0]
        pop     {r4, r5, r6, r7, pc}

And here's the resulting assembly with this commit applied:

_ldiv5:
        push    {r4, r5, r6, r7}
        movw    r4, #13107
        ldr     r6, [r0]
        movt    r4, 13107
        ldr     r1, [r0, #4]
        mov     r3, #0
        umull   r6, r7, r6, r4
        add     r2, r4, r4, lsl #1
        umull   r4, r5, r1, r4
        adds    r1, r6, r2
        adc     r2, r7, r2
        adds    ip, r6, r4
        adc     r1, r7, r5
        adds    r2, ip, r2
        adc     r2, r1, r3
        adds    r2, r4, r2
        adc     r3, r5, r3
        strd    r2, [r0]
        pop     {r4, r5, r6, r7}
        bx      lr

So we're down to 20 instructions from 36 initially, with only 2 umull
instructions instead of 3, and slightly smaller stack footprint.

Signed-off-by: Nicolas Pitre <[email protected]>
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3 participants