Parallella Community

I'm currently attempting to write a lightweight memory manager that's supposed to run on a single epiphany core. Now there's two questions I have:

1. Where is the C function stack stored, how large can it be potentially, and how do I avoid clashing with it?
2. How can I explicitly find out the address and size of the local memory of the current core, and how does that relate to my first question?

Thanks in advance!

The latest linker scripts handle the stack as follows:
PROVIDE (__stack_start_ = ORIGIN(INTERNAL_RAM) + LENGTH(INTERNAL_RAM) - 0x10);
.stack __stack_start_ : { ___stack = .; *(.stack) }

This sets the stack to grow from (highest sram address - 0x10) downwards.
There are no hardware limitations as to how large it can become, the software side of things is described by the linker file (not my area of expertise).

Local SRAM memory always starts at 0x00000000. Concerning the size, I don't think the default linker scripts actually export any symbols concerning the memory setup, modifying them might help you there. (You could also just add a #define, you know)

Yes starting at address zero is convenient, but don't put a heap there as the interrupt vector table lives there. The linker by default puts code after the table then areas for data. The SDK manual gives some more info. The heap mentioned there usually resides in external RAM. Though I suppose you could tell the linker to put it in local RAM instead. Then C malloc would use that RAM. Limited in size though.

Tim

If I may pose a related question : what is/are the typical/recommended assembly level instruction sequences/structures used to implement pushes and pops ?

[ That is : given that the only general register with implicit use is R14 ]

Cheers, Mike.