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chipsalliance / Cores-VeeR-EH1

VeeR EH1 core
Apache License 2.0
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problem with the linker and undefined reference errors ? #59

Closed mikemusasa closed 3 years ago

mikemusasa commented 4 years ago

HI ! Is there a problem with the linker when running a c code ? My c code includes all the necessary librarys and compiles separatly without a problem but i try to run it using the core , I keep getting undefine reference error for a lot of standard c funtions example printf ? anyone else had this error ?

the riscv64-unknown-elf-ld fails during the building

agrobman commented 4 years ago

You have to review your code and find what is missing (what linker complains about)

mikemusasa commented 4 years ago

I review my code, now whe i try to run it , i am getting some undefined reference errors to simple c funtions Like printf , fread, fopen even the headers to includes these librarys are there. I saw in the c mark code that they had to write their own printf type of functions . Does the linker have a problem finding their definitions ?

agrobman commented 4 years ago

The "simple C functions" are not that simple - there is a bunch of code to be executed by the CPU and computer HW/OS/BIOS.

You have to link all used libraries - Swerv Makefile doesn't do this.

However, non of the standard I/O library functions will work on provided TB.

Swerv TB can't execute OS functions as fopen or printif, which require some OS and HW. It does not have screen/display controller or any hard drive to support file system. I'm not sure that "-unknown-" tool chain even have all these I/O libraries, which are OS dependent...

You have to provide your own implementation for any I/O functions your program is using.

cmark code is an example of simple terminal emulation with printif function, based on putc function, which in the swerv TB just writes to a specific address. The TB monitors writes to this address on LSU bus to print on screen and a log file.