To address this, and leapfrog MS, BASIC XL included the new FAST command. When encountered in a program, the language searched the entire program looking for instances of GOTO/GOSUB with a simple line number (as opposed to a formula that returned a number) and replaced it with the address of the line. It did the same for NEXT statements. This offered a huge performance boost, making loops run as fast as MS, and the program as a whole even faster. The downside is that the address became invalid if the program was edited during runtime and it could not be CONTinued, unlike Atari BASIC which generally allowed this after any edit, but this had always been the case in MS anyway.