Shifted Screen Load

SHIFTED SCREEN LOAD


by Lopez Figueira


from Your Sinclair #26 (February 1988)


[files SHIFTSC1.*]





[NOTE: For this routine to work correctly with an emulator, the screen]


[must be saved as TZX format. Although the save routine will save to a]


[TAP file, the load routine will not recognise it as it uses its own ]


[loading code and does not call the standard ROM routine. JimG]





Lopez has sent both Basic and assembly code listings to help you under-


stand what's going on. The Basic listing is really designed for demon-


stration purposes, but can also be used to save a working sub-routine to


tape or microdrive by changing line 50 and adding lines 51 to 54:





50 SAVE "SHIFTSCR" CODE 65000,244


51 PRINT "REWIND TAPE TO VERIFY, THEN PRESS ANY KEY"


52 PAUSE 1: PAUSE 0


53 VERIFY "SHIFTSCR" CODE


54 STOP





The assembly listing has two entry points, LOADER to load the code and


BUILD to save a screen (BUILD a specially saved unit).