Computer system emulating a register window architecture by decoding the subject code to find the register window movements to encode the memory stack pointer

摘要

Disclosed is a computer system adapted to run register window architecture software. The computer has a decode unit that decodes the subject code to obtain the register window movements, and derive the window subject references from the register based instructions. The system has a memory stack and an encoder to generate target code from the decoded subject code. The target processor in the system executes the target code by setting a stack pointer to the head of the memory stack and adjusts the pointer using the register window movements and accesses the stack entries using the window subject references. The decoder may identify save and restore type movements, which are used by the target processor to adjust the stack pointer, possibly by a preset offset. If the subject code has a caller portion that performs a function call to a another portion the encoder unit may generate a single block of target code. The memory may be an emulated execution stack.