First of all its given that the computer/processor doesn't care whether the given number in binary is signed or unsigned number, depending on instructions it receives in op-code it performs signed or unsigned arithmetic, and in the given case it will interpret the number as signed or unsigned.
rs stores 11100 rt has 01000. Say it is supposed to do an unsigned arithmetic 11100 - 01000 the result would be obviously 10100 which is 20 in decimal notation, since we performed an unsigned arithmetic (subtraction). And this number is temporarily stored somewhere in the memory in a location address say "rd" to be used again.
Does this mean the number being stored at location rd can be used only for unsigned arithmetic in future.
If yes: please clarify the following. How does the computer actually know that it has to apply unsigned arithmetic whenever it used the data in rd the next time.where is the data related to this (that rd can only use unsigned arithmetic) stored.
So would this mean the computer really cares if the number being stored in address rd is signed or unsigned which will be a contradiction to first statement.
If no: why can it be used for a different type of arithmetic? wont doing this create any complications.