RE: [lwip-users] Problem With dns.c Using 32-Bit Compilers

[Goldschmidt Simon]

>> The problem with these DSP is that whatever the size of the operand, 
>> (8,
>> 16 or 32 bits), the compiler allways use 32bit "accesses". This is
due 
>> to the fact that these DSPs can manipulate only 32bit registers. 
>> Memory accesses are also only 32bit accesses.
> 
> Despite the optimal width of memory accesses the C6x does support a
load
> byte (ldb) instruction (very possibly implemented in silicon as a
32-bit
> read with a mask and shift to cope with the memory access
constraints).
> Either way, it doesn't prevent a compiler supporting a packed
structure
> and knowing it will have to assume it and all its members are
potentially unaligned.

Many processors I know don't support 8-bit or unaligned operations.
However,
the compiler fakes this: e.g. loading unaligned is done by loading
twice,
masking and shifting into one register.

Simon