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How to tread the different memory spaces?

Geert Vancompernolle

Hello,

Suppose you declare an array in a certain memory space, for instance 

unsigned char xdata SendBuffer[ 20 ];
.
Is it allowed to just prototype the callees with 
byte *SendBuffer
and dereference it as 
TempVal = *( SendBuffer + Counter );
?
Or should it be casted to the correct memory space, like 
TempValue = *( (unsigned char xdata*)SendBuffer + Counter );
?
In other words, is the Keil compiler 'clever' enough to see the memory space in the called functions and do the correct memory space conversion itself?
That means, if I declare my SendBuffer in 
idata
, will it also work correctly with the same prototype for the callees?

I've run the PC simulator and it seems it works fine, but I just want confirmation.

Rgds,

Geert

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  • 0 in reply to Drew Davis

    "you'll get more efficient code by using specific pointers"

    That depends upon your definition of "efficient"

    If you use Generic Pointers, the compiler will use Library calls to handle them; if you use memory-specific pointers, the compiler can put the code in-line.

    Thus, using memory-specific pointers can actually increase your code size - although execution speed should be improved.

    As I said, it all depends on what you mean by, "efficient"

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  • 0 in reply to Drew Davis

    "you'll get more efficient code by using specific pointers"

    That depends upon your definition of "efficient"

    If you use Generic Pointers, the compiler will use Library calls to handle them; if you use memory-specific pointers, the compiler can put the code in-line.

    Thus, using memory-specific pointers can actually increase your code size - although execution speed should be improved.

    As I said, it all depends on what you mean by, "efficient"

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