# Blocs d'activation
## Memory Hierarchy

| Type         | Desc                                |
| ------------ | ----------------------------------- |
| Registers    | Small memory units built on the CPU |
| L1           | Last main memory access results     |
| L2           | MB                                  |
| Memory (RAM) | RAM                                 |
| Storage      | Disks                               |

## Register overflow
**Memory allocation must be dynamic**
### Dynamic memory allocation
- *Global*
- *Automatic*
- *Heap*:
	- User controlled
	- Garbage collected
## `spim` Memory model
![[Pasted image 20250513142247.png]]

## Stack management
Function calls: stack process
Or: Call Tree dfs

## Activation blocks contents
- arguments : incoming
- local variables : user automatic variables
- return address : where to return
- saved registers : caller's environment to restore
- temp : compiler automatic variables, spills
- static links : when needed
Layout suggested by the constructor

## Frame & stack pointer
Frame : debut de bloc
Stack : fin de bloc

# Static links
A mechanism :
- Computed at compile time
- that produces code
- that will be used at runtime
$\rightarrow$ Sert à remonter au premier lien avant les appels recursifs pour chopper des variables

# Translating expressions
How to translate the expression $\alpha < \beta$ in HIR?