[lwip-devel] [bug #26273] etharp.c : fix alignment issue in etharp_raw

[Guillaume du PONTAVICE]

Follow-up Comment #14, bug #26273 (project lwip):

ok guys,
I checked with ST, I was not using the latest compiler.
this was a known issue, unfortunately compiler release are not public & are
only given by ST support.

with the latest compiler, the assembly output looks like this

..1463: -- Line 1080 (lwip/src/netif/etharp.c) 
        ldl     11      -- ipsrc_addr
        ldl     2       -- hdr
        ldnlp   7
        ldc     4
        move
..1464: -- Line 1081 (lwip/src/netif/etharp.c) 
        ldl     13      -- ipdst_addr
        ldl     2       -- hdr
        adc     38
        ldc     4
        move


move : This interprets AREG as an unsigned integer representing the number of
bytes to be transferred, BREG as the destination address, and CREG as the
source address.

everything is working fine now.

anyway I agree that compiler behaviour on struct assignement shall be
reviewed as well, to minimize memcpy call overhead. (even if it looks like
ST20 has a specific opcode to perform memcpy, it could be useful for other
target/compiler)

thanks for your support, guys !

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