Software Lower Case

are displayed as regular capital letters on the screen. Now. when we want 'UPPER CASE", we hold down the shift key and type a letter Such a letter should then be given a special designation on the screen Here, we will precede It with a small graphics block, to show that It is "UPPER CASE" The printer routine, when ceiled by LPRINT or LLIST then, wilt print regular (unahffted) letters as true lower caae and shitted letters as upper case. This means, of course, that BASIC keywords will come out printed aa if-then-else instead of IF-THEN-ELSE during a LLIST, but II won't affect the behavior ol the program one bit. The assembly Haling shown In Figure 1 accomplishes these teats with three modules: 1) A stan block (START) to link the other iwo modules Into the Display and line printer calling sequences. 2) A display driver (SDSPLY). which precedes every shifted letter on the screen by a graphic block and erases the block in the event ol a backspace, and 3) A printer driver (SPRINT), which reverses the shift of all letters going to the printer

To use this program, enter the source code Dhown Into the editor/aasembier. assemble it. and make a SYSTEM tape. Then initialize LEVEL II BASIC (ORG 7FABH assumes 16K) and sal memory size to 32683. Load the SYSTEM tape, type the /ENTER to execute the start block, and BASIC will be ready with Its new lower case personsiity • all without even having to plug In a soldering Iron! m

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