Threaded Mode | Linear Mode

Thomas Okken · (This post was last modified: 11-22-2020 07:56 PM by Thomas Okken.)

(11-22-2020 07:01 PM)[kby] Wrote: Regardless of the program steps in the original program, reading a program card should overwrite the old program so there is no place to continue other than the first step of the new program, no?-kby

No. When a program is loaded with MERGE, it is loaded after the current line. So, from a program that uses the sequence MERGE PAUSE, the program is loaded after the PAUSE.

In both cases, execution continues at step 1 of the loaded program. The difference lies in where in program memory that program ends up.

It just occurred to me that there is another experiment I should do, namely, check what happens if MERGE is performed while there is a pending RTN to a location after the MERGE. A pending RTN to a location before the MERGE works as expected, but a location after the MERGE doesn't really make sense, so how is that handled?

UPDATE: There's no special handling for bogus RTN locations. So, if at the time of the MERGE, there is a pending RTN to somewhere after that MERGE, execution will still return to that location, even though it has been overwritten.