[Coco] Proposed change on coVDG (level1)

[Robert Gault]

Luis Antoniosi (CoCoDemus) wrote:
> But that is intended :). $60 is acute accent.
>
> The old code replaced $60 to $67 (apostrophe). I think it should be $27
> (reverse apostrophe) to make the distinction between apostrophe and acute
> accent symbol. What do you think ? How do you know you typed apostrophe or
> acute accent if they look the same ???
>
> Luis Felipe Antoniosi
>

Louis,

I've had a change to look more closely at your proposed code. For one thing you 
ignore whether there is true lower case available.

ldb <V.CFlag,u
cmpa #$40 numbers ?

The value in V.CFlag is ignored and that indicates true false lower case.


Why not try transplanting the code from Level2 covdg if you think that is the 
main factor in screen writing speed?

Here is the equivalent section of code.

          tsta
          bmi   L01BA
          ldb   <VD.CFlag,u
          beq   L019A
          cmpa  #$5E
          bne   L018A          re-map characters from ASCII-VDG
          clra
          bra   L01BA
L018A    cmpa  #$5F
          bne   L0192
          lda   #$1F
          bra   L01BA
L0192    cmpa  #$60
          bne   L01AA
          lda   #$67
          bra   L01BA

L019A    cmpa  #$7C          true lowercase
          bne   L01A2
          lda   #$21
          bra   L01BA
L01A2    cmpa  #$7E
          bne   L01AA
          lda   #$2D
          bra   L01BA
L01AA    cmpa  #$60
          bcs   L01B2          re-map ASCII
          suba  #$60
          bra   L01BA
L01B2    cmpa  #$40
          bcs   L01B8
          suba  #$40
L01B8    eora  #$40

CFlag is used to provide different routines for true/false lowercase.

Robert