In MCS keywords are reformatted on the fly - but for display purposes only. The case in which you type it in is what's stored in the actual file. If you typ HsERiN that's what stored when you save the file even if MCS displays HSERIN on the screen.

define is a keyword so when you type that in MCS it gets reformatted to upper case (if you have your formatting setup that way) but if you then copy/paste that into Notepad or whatever it reverts to the way you typed it (which can be DefINe or whatever). OSC on the other hand - which is the important thing here - is NOT a keyword that MCS recognizes so it does NOT get reformatted and that's a good thing in this case because if it did you'd see OSC on the screen even if you typed it as osc which would then cause the assembler to not recognize it as OSC.

/Henrik.