Dear Helper, When "call" instruction is executed (or earlier decoded), I know that the return address should be pushed to a stack (stack-register) if more that a call will be needed. My question is do I also have to push the condition code register (N, Z,V, and C) and then pop them again with the return address when return from call (rfc) instruction is executed or I just push the return address (the PC of the call + 2 for 16-bit processor). I am thinking to push only the return address to the stack-register during call and I push the "ra" and CCR flags for interrupt only. Many thanks, /Ben UEC, IS -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/openrisc/attachments/20040514/ca989758/attachment.htm