[lwip-users] RE: [lwip] netif alignment

[Wurmsdobler, Peter]

Hello,

>  And doesn't it in your case ?
No.

> ... Do you need it aligned and unless
> you change the layout of the struct it can't access some fields?
> That's weird.
Yes, it is. I was debugging for half a day, because I did not expect 
to be there. Then I printed the address of the netif structure, and
the contents of the function pointer. In the assembler code I could
see that to the address of the structure an offset of 24 was added,
 
   fwipif->input (p, fwipif);
 590:   d1 0a           mov.l   5bc <_ip1394ip_input+0x5c>,r1   ! 0x0
 592:   65 12           mov.l   @r1,r5
 594:   50 56           mov.l   @(24,r5),r0  <--here !
 596:   40 0b           jsr     @r0
 598:   64 23           mov     r2,r4

even though the offset to the input function in the structure is 23.
Rearranging the structure to be at least 16bit aligend and it worked.
It this is a valid explanation, I do not know, but now it works and
I have a ping time of 1ms !
peter
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