THE-OPPOSITE-SIDE-THE-NEGATIVE-ONE
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TOOL: 		Machine-Language-Monitor {Commodore C128 Built-In}
Language: 	Assembler 
Extra:		-
Author: 	Misel Zivanovic
Note:		(C) 13th July 2026  - www.lived.ch, mzretro.ch
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What is this code doing?

Being NEGATIVE, doesn't always need to mean to also be BAD, right!
Recently i had to make a big text characters, you know, something like that:

aa  aa  aaaaaa  aa      aa      aaaaaa
aa  aa  aaaaaa  aa      aa      aaaaaa
aa  aa  aa      aa      aa      aa  aa 
aaaaaa  aaaaaa  aa      aa      aa  aa
aaaaaa  aaaaaa  aa      aa      aa  aa
aa  aa  aa      aa      aa      aa  aa
aa  aa  aaaaaa  aaaaaa  aaaaaa  aaaaaa
aa  aa  aaaaaa  aaaaaa  aaaaaa  aaaaaa

And then i thought it would be nice to have this also in inverse!
Can't be so difficult to do it in assembler. I had something similar done in COMAL-80
Well, I quickly put this together, and guess, it's working!

You are right, there are other ways to do this, but why sweat unnecessary.
I just need it for the text size of 12 lines, not the whole screen.

You are free to extend it as you wish or even add more functionality.
Should not be a problem if you have followed all previous lessons until here!


Assembly Code
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d 1300 1330

. 01300  a2 00    ldx #$00
. 01302  bd 00 04 lda $0400,x
. 01305  c9 20    cmp #$20
. 01307  f0 17    beq $1320
. 01309  a9 20    lda #$20
. 0130b  9d 00 04 sta $0400,x
. 0130e  bd f0 04 lda $04f0,x
. 01311  c9 20    cmp #$20
. 01313  f0 13    beq $1328
. 01315  a9 20    lda #$20
. 01317  9d f0 04 sta $04f0,x
. 0131a  e8       inx
. 0131b  e0 f0    cpx #$f0
. 0131d  d0 e3    bne $1302
. 0131f  60       rts
. 01320  a9 51    lda #$51
. 01322  9d 00 04 sta $0400,x
. 01325  4c 0e 13 jmp $130e
. 01328  a9 51    lda #$51
. 0132a  9d f0 04 sta $04f0,x
. 0132d  4c 1a 13 jmp $131a
. 01330  00       brk



Machine Language Code
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m 1300 1330

>01300 a2 00 bd 00 04 c9 20 f0:B.?..I P
>01308 17 a9 20 9d 00 04 bd f0:.I ...?P
>01310 04 c9 20 f0 13 a9 20 9d:.I P.I .
>01318 f0 04 e8 e0 f0 d0 e3 60:P.H?PPC?
>01320 a9 51 9d 00 04 4c 0e 13:Iq...l..
>01328 a9 51 9d f0 04 4c 1a 13:Iq.P.l..




PREVIEW: NORMAL
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          qqqqq
          qqqqq
          qq
          qqqqq qqq qqqqq qqqqq
          qqqqq qqq qq qq qq
          qq    qqq qqqqq qqqq
          qq    qqq qqqq  qq
          qq    qqq qq qq qqqqq


PREVIEW: INVERSE
{looks better on the screen!!!}
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QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ
QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ
QQQQQQQQQQ     QQQQQQQQQQQQQQQQQQQQQQQQQ
QQQQQQQQQQ     QQQQQQQQQQQQQQQQQQQQQQQQQ
QQQQQQQQQQ  QQQQQQQQQQQQQQQQQQQQQQQQQQQQ
QQQQQQQQQQ     Q   Q     Q     QQQQQQQQQ
QQQQQQQQQQ     Q   Q  Q  Q  QQQQQQQQQQQQ
QQQQQQQQQQ  QQQQ   Q     Q    QQQQQQQQQQ
QQQQQQQQQQ  QQQQ   Q    QQ  QQQQQQQQQQQQ
QQQQQQQQQQ  QQQQ   Q  Q  Q     QQQQQQQQQ
QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ
QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ


sys 4864

ready.