Structured programming

Question 1

How is a program started

Answer 1

pc starts at 0 and mem[0 contains a jump instuction to start of program in memory

Question 2

what is stored between 0 and the start of a program

Answer 2

constants globals and strinsg

Question 3

what does the stack store

Answer 3

local variables and support subroutine calls

Question 4

what si the stack pointer

Answer 4

stores the memory location to the top of the stack

Question 5

how are subroutine calls performed using the stack

Answer 5

caller local variables and subroutine parameters pushed to the stack
(caller -> function which makes the call)
push the return address -> the address to go to after the subroutine
(ldap 1)
update the stack pointer
once returnvalue is calculated add it to the stack frame

Question 6

How does a subroutine end using the stack

Answer 6

stack pointer is updated (often incremented because the stack is often from high to low)

return address is oppped and used for a jump instruction
rest of the data is popped off