Add the rest of university notes

docs/lectures/compilers/03_TAM.md

@@ -0,0 +1,129 @@
+# Triangle Abstract Machine
+
+**TAM** instruction set
+
+```assembly
+LOADL (int)
+NEG
+ADD
+SUB
+MUL
+DIV
+```
+
+TAM works on a stack of integers. 
+
+##### Executing a TAM program
+
+```assembly
+LOADL 7
+ADD --adds top two numbers on the stack
+LOADL 2
+SUB -- note its 15-2
+LOADL 4
+DIV --integer division
+```
+
+The stack during this program:
+
+$$
+\begin{bmatrix}
+{8} \\
+{5}
+\end{bmatrix}
+\implies
+\begin{bmatrix}
+{7} \\
+{8} \\
+{5}
+\end{bmatrix}
+\implies
+\begin{bmatrix}
+{15} \\
+{5}
+\end{bmatrix}
+\implies
+\begin{bmatrix}
+{2} \\
+{15} \\
+{5}
+\end{bmatrix}
+\implies
+\begin{bmatrix}
+{13} \\
+{5}
+\end{bmatrix}
+\implies
+\begin{bmatrix}
+{4} \\
+{13} \\
+{5}
+\end{bmatrix}
+\implies
+\begin{bmatrix}
+{3} \\
+{5}
+\end{bmatrix}
+$$
+
+## Compiler Complete Example
+
+Program in **Arith**
+
+```c
+5 * ((8 + 7) - 2) / 4
+```
+
+**A**bstract **S**yntax **T**ree
+
+![img](img/h.png)
+
+**TAM** program
+
+```assembly
+LOADL 5
+LOADL 8
+LOADL 7
+ADD
+LOADL 2
+SUB
+LOADL 4
+DIV
+MUL
+```
+
+## Implementing TAM in Haskell
+
+```haskell	
+module TAM where
+
+data TamInstruction = LOADL Int
+					| ADD | SUB
+					| MUL | DIV
+					| NEG
+					deriving(Eq, Show)
+type Stack = [Int]
+
+execute :: [TamInstruction] -> Stack -> Stack
+execute [] s = s --if stack empty, then return the stack
+execute (LOADL n : tp) s = execute tp (n : s) --push n to top of stack
+execute (ADD : tp) (a : b : s) = execute tp ((a+b):s) --push a+b
+...
+execute (DIV : tp) (a : b : s) = execute tp ((a`div`b):s)
+```
+
+Quicker way to write the execute function using `absOpToConcrOp`
+
+```haskell
+convOp :: TamInstruction -> Int -> Int -> Int
+convOp ADD = (+)
+convOp SUB = (-)
+convOp MUL = (*)
+convOp DIV = (`div`)
+
+execute :: [TamInstruction] -> Stack -> Stack
+execute [] s = s
+execute (LOADL n : tp) s = execute tp (n : s)
+execute (NEG : tp) (a : s) = execute tp (-a : s)
+execute (op : tp) (a : b : s) = execute tp ((convOp op a b) : s)
+```