CHARACTER GENERATOR |
Refering
back to the `key` character to display it on the screen, first put the
`key` data in the computer by entering the `Monitor` type .M 3200 3208 then press `Return` you will see a row of 8 two character value numbers. Starting with the left 1st value number type over each one with the `key` value numbers starting with the top one (`0F`). After entering all the 8 (`key`) value numbers please remember to press `Return` after the 8th value number. You must have in your program the `Character Generator` routine below to get all your design characters to be displayed. The `Character Generator` generates characters starting at address `3200` which displays the code number `40` the next code number(`41`) at address `3208` the next code number (`42`) at address ` 3210` and so on. Please note again a `character` takes up 8 addresses. Type in the `Character Generator` routine and the `Key` program below. Character Generator:- Clear the screen and type:- .A 40B0 LDA $D018 .A 40B3 AND#$F0 .A 40B5 STA$D018 .A 40B8 LDA$D018 .A 40BB ORA#$0C .A 40BD STA$D018 .A 40C0 LDA$DC0E .A 40C3 AND#$FE .A 40C5 STA$DC0E .A 40C8 LDA$01 .A 40CA AND#$FB .A 40CC STA$01 .A 40CE LDX#$00 .A 40D0 LDA$D000,X .A 40D3 STA$3000,X .A 40D6 LDA$D100,X .A 40D9 STA$3100,X .A 40DC INX .A 40DD BNE$40D0 .A 40DF LDA$01 .A 40E1 ORA#$04 .A 40E3 STA$01 .A 40E5 LDA$DC0E .A 40E8 ORA#$01 .A 40EA STA$DC0E .A 40ED RTS Key program:- Clear the screen and type:- .A 4000 JSR$40B0 [call to address 40B0 (character generator)] .A 4003 JMP$4020 [ jump to address 4020 (program main loop)] Clear the screen and type:- .A 4020 JSR$E544 [call rom routine to clear the screen] .A 4023 LDA#$40 [ load `A` with code value number `40`(`key character`] .A 4025 STA$0400 [store value of `A` into address 0400 (top left of screen)] .A 4028 JMP$4023 [jump to address 4023 to keep program running] Please do not enter in the `Monitor` after the commands the `brackets [ ]`and the `information`.The information is there only for reference. Clear the screen type .X and press `Return` to return to `basic`.Type SYS16384 to run the `key` program, you will see a `key` at the top left hand corner of the screen. Press `Stop/Restore` to return to `basic`. Should you want to display your own design `characters` in your future programs, you must put in your program the `Character Generator` routine and call the routine at the start of your program also enter the `data` for all of your `characters` at the approx. addresses and part of your program that prints the characters on screen. |