GCC M68K PC相对

Question

I was using a Microtek toolchain to generate an executable binary with relocatable code (pc-relative) and data from a fixed address (Absolute data). Today, this toolchain does not work on Windows 7 64 bits. The idea is to replace Microtek toolchain for 68000 with the GNU toolchain (GCC 4.8.0).

But I can not find the same options on the gcc compiler:

Microtec compiler "MCC68K" with: "-Mcp": Directs the compiler to use PC-relative addressing for all code references. "-Mda": Directs the compiler to use absolute addressing for all data references.

Gcc (m68k-elf-gcc) with: -mpcrel

Unable to build with gcc relocatable code with no relocatable data as the Microteck compiler. With "-mpcrel", all is relocatable (code and data).

do you have an idea?

Sorry for my bad english.

Thanks.

Answer 1

As far as I know, there is no way to achieve the same result with the GNU m68k toolchain.

• -mpcrel will generate fully position-independent code with pc-relative adressing for code as well as for data, resulting in a limited program/data size (pc-relative offsets cannot exceed 16 bits).
• -fpic and -fPIC will generate position independent code with relocatable binaries but will require a special loader that does the in-place relocation

Answer 2

From gcc docs

-fpic Generate position-independent code (PIC) suitable for use in a shared library,...

-fPIC If supported for the target machine, emit position-independent code, suitable for dynamic linking and avoiding any limit on the size of the global offset table.

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