1. The Stack

2. The Stack ARMSim memory space: 0x11400 + Unused 0x09400-0x11400 Stack
Heap
0x?????-0x01400
Data
0x x?????
Text
0x x01000
Reserved

3. Stack possibilites How to use the space in stack? Grow up
Keep track of top item in stack (Full Ascending)
Keep track of first empty slot (Empty Ascending)

4. Stack possibilites How to use the space in stack? Grow down
Keep track of top item in stack (Full Descending)
Keep track of first empty slot (Empty Descending)

5. Stack possibilites ARM Convention : Full Descending
r13 Points to "top" item (lowest address) in stack
Stack view of memory flipped

6. Push Recipe Subtract 4 from sp … 81818181 0x113F4 0x113F8 0x113FC
????????? sp
0x11400

7. Push Recipe Subtract 4 from sp … 81818181 0x113F4 0x113F8 0x113FC
????????? sp
0x113FC

8. Push Recipe Subtract 4 from sp STR data … 81818181 0x113F4 0x113F8
0x113FC AA
0x11400
????????? sp
0x113FC

9. Push Recipe Subtract 4 from sp … 81818181 0x113F4 0x113F8 0x113FC AA
????????? sp
0x113F8

10. Push Recipe Subtract 4 from sp STR data … 81818181 0x113F4 0x113F8 BB
0x113FC AA
0x11400
????????? sp
0x113F8

11. Pop Recipe LDR data … 81818181 0x113F4 0x113F8 BB 0x113FC AA 0x11400
????????? sp
0x113F8

12. Pop Recipe LDR data Add 4 to sp … 81818181 0x113F4 0x113F8 BB 0x113FC
????????? sp
0x113FC

13. Pop Recipe LDR data … 81818181 0x113F4 0x113F8 BB 0x113FC AA 0x11400
????????? sp
0x113FC

14. Pop Recipe LDR data Add 4 to sp … 81818181 0x113F4 0x113F8 BB 0x113FC
????????? sp
0x11400

15. Push / Pop Always tear down stack in reverse order Push A Push B Pop B
Time

16. Machine Push/Pop Fun Fact Common need : machine instructions
Store Multiple to Full Descending use sp and update it (!) store r1 and r2

17. Machine Push/Pop Fun Fact Common need : machine instructions
Load Multiple from Full Descending use sp and update it (!) load r2 then r1 (reverse order)

18. Pseudo Instructions
Easier pseudinstructions: PUSH {register list} POP {register list}