(related to Definition: LOOP Command, LOOP Program)
The basic syntax and semantics of a \(L O O P\) program is very plain and simple: It is only possible to increment and decrement a register and repeat a \(L O O P\) program a number of times. However, using these basic commands, it is possible to simulate a lot of more complex commands, among others:
the assignment of a constant value to a register, \[\mathtt{r_i:=c;}\]
setting the value of a register to the value of another register plus/minus a constant, \[\mathtt{r_i:=r_j\pm c;}\]
checking if a register equals \(0\) and, based of this comparison, a conditional execution of a \(L O O P\) program (if-then-else construct), \[\mathtt{IF~r_i=0~THEN~P_1~ELSE~P_2~END;}\]
checking if a register is greater then a constant value and, based of this comparison, a conditional execution of a \(L O O P\) program (if-then construct), \[\mathtt{IF~r_i > c~THEN~P~END;}\]
the no-operation command (NOP command), \[\mathtt{NOP;}\]
addition (or subtraction) of two registers, \[\mathtt{r_i:=r_j\pm r_k;}\]
multiplication of two registers, \[\mathtt{r_i:=r_j\ast r_k;}\]
division with quotient and remainder, \[\begin{array}{l} \mathtt{r_q:=r_j~DIV~r_k;}\\ \mathtt{r_r:=r_j~MOD~r_k;} \end{array}\]
and many more...
