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Nios Addressing

Hello,

I have found a problem with a C++ Code,

if i have a Buffer of "unsigned char" (for example 00 00 00 00 37 00 00 20

00 ecc..ecc.) ,i want to get a DWORD value from the 5 byte they should be return 00 00 20 00 sequence, instead they give me the result from 37.... (a 4 bytes pairs)... if i try from 6 or 7 byte , they returned me the same value , also from the 8 byte give me a new correct value.. the Nios can't addressing the offset of 4bytes? , the same code compiled on pc work great..

Thank's a lot

Reply to
Luigi Padovani
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(snip)

Many machines require data to be aligned on a boundary matching the size of the data. A four byte DWORD should have an address that is a multiple of four.

Yes, x86 doesn't require that but it is much slower when doing a fetch like that. It is not legal in C, and I don't believe in C++ to do that. Copy it character by character (memcpy in C) to a properly aligned variable.

-- glen

Reply to
glen herrmannsfeldt

I believe you can use the __attribute__ option to the DWORD variabele. You just need a look in the documentation what type of attribute you have to specify for alignment.

I'm sure it works on structs.

20

(a

great..

Reply to
Vanheesbeke Stefaan

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