1. [M] In addition to the processor stack, it may be convenient to use another stack in some programs. The second stack is usually allocated a fixed amount of space in the memory. In this case, it is important to avoid pushing an item onto the stack when the stack has reached its maximum size. Also, it is important to avoid attempting to pop an item off an empty stack, which could result from a programming error. Write two short RISC-style routines, called SAFEPUSH and SAFEPOP, for pushing onto and popping off this stack structure, while guarding against these two possible errors. Assume that the element to be pushed/popped is located in register R2, and that register R5 serves as the stack pointer for this user stack. The stack is full if its topmost element is stored in location TOP, and it is

empty if the last element popped was stored in location BOTTOM. The routines should branch to FULLERROR and EMPTYERROR, respectively, if errors occur. All elements are of word size, and the stack grows toward lower-numbered address locations.