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FW: [M16C] : 20 bit data pointer
- From: "Naveen H.S." <naveen dot hs at kpitcummins dot com>
- To: <gcc at gcc dot gnu dot org>
- Date: Thu, 12 Apr 2007 17:44:57 +0530
- Subject: FW: [M16C] : 20 bit data pointer
Hi,
M16C has 20 bit physical address bus, but the address registers are
only 16 bit. It has a 16 bit data pointer. ROM memory region starts
at memory location "0x000A0000" (i.e. 20 bit address). As the pointer
size for GCC M16C is two bytes, it fails to access the memory region
that is greater than 16 bits.
So there is problem while accessing the "const" data and hard-coded
strings which by default get placed in section ".rodata" section.
Currently the complete ".rodata" section is copied from load address
(ROM) to RAM, that is by treating it similar to ".data" section.
We went through the discussion in the following link and realized that
there should not be 2 pointers for the same data type as of now.
http://gcc.gnu.org/ml/gcc-patches/2005-08/msg01129.html
Can the size of data pointer be increased to 20 bit? If yes, please
guide me in implementing the same.
Regards,
Naveen.H.S.
KPIT Cummins Infosystems Ltd,
Pune (INDIA)
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Free download of GNU based tool-chains for Renesas' SH, H8, R8C, M16C
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Latest versions of KPIT GNU tools were released on February 6, 2007.
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