im looking for a way to turn the bright flag on and off in assembler

[777]

my program contains a loop that changes the ink and the paper colour in assembler.

here:

Code: Select all

ORG 40000
  CALL $daf
;ld a,$16
;rst 16
;ld a,0
;rst 16
;ld a,0
;rst 16
  LD A,33
ld b,8
ld c,0
ld d,0
LOOP:  
  CP 165
  RET Z
  PUSH AF
  RST 16
  ;ld a,8
;rst 16
ld a,$10
rst 16
ld a,b
add a,-1
rst 16
ld a,$11
rst 16
ld a,c
rst 16
inc c
;ld a,$13
;rst 16
;ld a,d
;rst 16
pop af
  INC A
djnz loop
ld b,8
ld c,0
;inc d
jr loop

how do i turn the bright flag on and off? the bright flag will only accept 1 or 0. is there an instruction that i can use that will go from 1 and back to 0 constantly? or even after 7 steps which is what is happening within the ink and paper routine of this program

* look at the bits of code that i have commented out at the bottom

[Waldroid]

If you use an XOR $40 instruction to operate on each byte in the attributes it will toggle the BRIGHT bit each time it's run.

[777]

If you use an XOR $40 instruction to operate on each byte in the attributes it will toggle the BRIGHT bit each time it's run.

ok, i did try that but it only does 1 loop. where do i put it?

[Waldroid]

I'm looking through your code... Are you trying to print a line of exclamation marks in different colours?

[777]

I'm looking through your code... Are you trying to print a line of exclamation marks in different colours?

no. if you run it, it prints from ! to udg u across the screen in different inks and paper colours.

[Waldroid]

Okay, I think this is what you're after. It makes every other character be bright.

Code: Select all

    ORG 40000

    CALL $daf                   ; Does a CLS.
    LD A,33                     ; Stores the current character, starting at '!'.
    ld b,8                      ; Stores ink colour.
    ld c,0                      ; Stores paper colour.
    ld d,0                      ; Not used.
    ld h,0                      ; Stores bright flag on/off (1/0).
LOOP:  
    CP 165                      ; Return when past the last UDG.
    RET Z
    
    PUSH AF
    RST 16

    ld a,$10                    ; Set ink colour...
    rst 16
    ld a,b
    add a,-1                    ; ... to iteration minus 1.
    rst 16
    
    ld a,$11                    ; Set paper colour.
    rst 16
    ld a,c
    rst 16
    inc c                       ; Increment colour for next character.

    ld a,$13                    ; Set bright flag.
    rst 16
    ld a,h
    xor 1                       ; Toggle flag for next character.
    ld h,a
    rst 16

    pop af

    INC A                       ; Move to the next character code.
    djnz LOOP
    
    ld b,8                      ; Reset ink and paper colours.
    ld c,0

    jr LOOP

[777]

Okay, I think this is what you're after. It makes every other character be bright.

Code: Select all

    ORG 40000

    CALL $daf                   ; Does a CLS.
    LD A,33                     ; Stores the current character, starting at '!'.
    ld b,8                      ; Stores ink colour.
    ld c,0                      ; Stores paper colour.
    ld d,0                      ; Not used.
    ld h,0                      ; Stores bright flag on/off (1/0).
LOOP:  
    CP 165                      ; Return when past the last UDG.
    RET Z
    
    PUSH AF
    RST 16

    ld a,$10                    ; Set ink colour...
    rst 16
    ld a,b
    add a,-1                    ; ... to iteration minus 1.
    rst 16
    
    ld a,$11                    ; Set paper colour.
    rst 16
    ld a,c
    rst 16
    inc c                       ; Increment colour for next character.

    ld a,$13                    ; Set bright flag.
    rst 16
    ld a,h
    xor 1                       ; Toggle flag for next character.
    ld h,a
    rst 16

    pop af

    INC A                       ; Move to the next character code.
    djnz LOOP
    
    ld b,8                      ; Reset ink and paper colours.
    ld c,0

    jr LOOP

sorry, this doesnt seem to work. it just sets the bright flag to 1 across all the characters

[Waldroid]

It works here. I assembled it using pasmo and tested it in fuse.

[777]

It works here. I assembled it using pasmo and tested it in fuse.

sorry, it is working, its just hard to see the way the bright is laid out

[Waldroid]

No need to thank me or anything...

[777]

No need to thank me or anything...

sorry, thanks