I'll clarify the question. I built a simple Ethernet switch model and
wanted to use EthAddr to store MAC address in the switch table, which would
be a std::map<uint64_t, EthInt*>. Looking at the code it seemed EthAddr was
only used in the NIC, and in that case it only used the ctor that takes in
a string, as well as the uint64_t cast operator, which allowed the NICs to
cast from a string to uint64_t to set their macAddr.
However the other ctors take in either an array or reference to an eth_addr
struct and do initialization like:
*data = *ea;
or
*data = *ea.data
Which is equivalent to: data[0] = ea[0] or data[0] = ea.data[0]. All the
class methods - with the exception of the overloaded uint64_t cast operator
- only utilize data[0] as well:
const uint8_t *bytes() const { return &data[0]; }
uint8_t *bytes() { return &data[0]; }
const uint8_t *addr() const { return &data[0]; }
bool unicast() const { return data[0] == 0x00; }
bool multicast() const { return data[0] == 0x01; }
bool broadcast() const { return data[0] == 0xff; }
I had to modify this class to make it more robust, and I was wondering if
this class was never completed or if this is the intended usage.
Anthony Gutierrez
http://web.eecs.umich.edu/~atgutier
On Fri, May 23, 2014 at 2:11 AM, Steve Reinhardt via gem5-dev <
gem5-dev@gem5.org> wrote:
> It's an ethernet address (for binding to ethernet NICs). Note that it
> (confusingly) corresponds to the python param class called 'EthernetAddr',
> which is why grepping just for 'EthAddr' makes it look less used than it
> is.
>
> Maybe I'm not looking at the same code you are, but I don't see what you're
> saying about only operating on data[0].
>
> Steve
>
>
>
> On Thu, May 22, 2014 at 11:28 AM, Anthony Gutierrez via gem5-dev <
> gem5-dev@gem5.org> wrote:
>
> > Hello,
> >
> > Can someone tell me what EthAddr was supposed to be used for? grepping
> > shows that it isn't really used for anything? I'm curious as to why all
> the
> > constructors and methods only operate on data[0]. Is there any reason
> all 6
> > bytes are not used?
> >
> > Thanks,
> > Anthony Gutierrez
> > http://web.eecs.umich.edu/~atgutier
> > _______________________________________________
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> > gem5-dev@gem5.org
> > http://m5sim.org/mailman/listinfo/gem5-dev
> >
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