Re: [avr-gcc-list] Query regarding hard located variables

[avr-gcc]

address@hidden wrote:

 > ATMega128. This register which I am discussing is not internal to
 > the processor.  It is a bank switching register for the second half
 > of the ATMega128 data space (ie addresses > 0x7fff can be bank
 > switched). Basically, it is located at 0x7fff. We still want to be
 > able to use addresses > 0x7fff for data (and can guarantee that the
 > correct page will be swithed in when necessary)

In that case, write a linker script of your own.  Decrease the amount
of available RAM by one byte, so it'll end up right before 0x7fff.
Invent a hardware memory section and an ELF section of your own for
the single address 0x7fff in the linker script.  Then place your
variable to access the bank switching register into that section.

You need to initialize this variable to your desired value manually at
program startup, gcc's framework will only handle the initialization
of the .bss (to 0) and .data sections (to the values provided as
initializers in the C program).

--
J"org Wunsch                                           Unix support engineer
address@hidden        http://www.interface-systems.de/~j/
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