zamiana znakow

:BasicUpstart2(main)

//----------------------------------------------------------
// Code for creating the breakpoint file sent to Vice.
//----------------------------------------------------------
.var _useBinFolderForBreakpoints = cmdLineVars.get("usebin") == "true"
.var _createDebugFiles = cmdLineVars.get("afo") == "true"
.print "File creation " + [_createDebugFiles
    ? "enabled (creating breakpoint file)"
    : "disabled (no breakpoint file created)"]
.var brkFile
.if(_createDebugFiles) {
    .if(_useBinFolderForBreakpoints)
        .eval brkFile = createFile("bin/breakpoints.txt")
    else
        .eval brkFile = createFile("breakpoints.txt")
}
.macro break() {
.if(_createDebugFiles) {
    .eval brkFile.writeln("break " + toHexString(*))
    }
}

.label screen_memory = $0400
.label memory_setup_register = $d018

.label character_rom = $d000

main:
:break()
  :clear_screen()
  :print_all_characters()

  :choose_character_set(4)

  sei
  lda $01
  pha
  and #%11111011
  sta $01

.for (var char = 0; char < 64; char++) {
  ldx #0
  ldy #7
loopx:
  lda character_rom + char*8, X
  sta custom_charset + char*8, X
  sta custom_charset + [64+char]*8, Y

  dey
  inx
  cpx #8
  bne loopx
}

  pla
  sta $01
  cli

  rts

.pc = 4*2048 "Custom Charset"
custom_charset:
.for (var char = 0; char < 256; char++) {
  .if (char == ' ') {
    .byte %00000000
    .byte %00000000
    .byte %00000000
    .byte %00000000
    .byte %00000000
    .byte %00000000
    .byte %00000000
    .byte %00000000
  } else {
    .for (var i = 0; i < 8; i++) {
      .byte char & 1<<i
    }
  }
}

.macro choose_character_set(index) {
  lda memory_setup_register
  and #%11110001
  ora #[index << 1]
  sta memory_setup_register
}

.macro clear_screen() {
  ldx #250
  lda #' '
loopx:
  .for (var i = 0; i < 4; i++) {
    sta screen_memory + 250*i - 1, X
  }
  dex
  bne loopx
}

.macro print_all_characters() {
  .for (var i = 0;i < 256; i++) {
    .var column = mod(i,32) + 4
    .var row = floor(i / 32) + 4

    lda #i
    sta screen_memory + row*40 + column
  }
}