I am wondering, if in the LOOP programing language, whether instances of the
LOOP x DO P END are defined to stop in the case $x < 0$.
The definition only says "Execute $P$, $x$ times" for the above program.
IT is perfectly clear for $x = 0$. However, I believe in order to keep the language simple the definition doesn't extend to the case $x < 0$.
If it were possible, then it would for instance basically shorten a $x_1\ div\ x_2$ operator to just one line:
x_0 = 0; LOOP x_1 DO x_1 = x_1 - x_2; x_0 = x_0 + 1; END
If it is not possible, is there any other reason except for reasons of convention?