Hello world asm question

[Craig]

I've got the code below that works when I use the CHROUT function, but when I change it to console_put_char, I see no output.  I see similar problems with other new x16-specific new kernel functions.  So can we assume those functions are not fully implemented yet?

Thanks,

Craig

    ldx #0
again:
    lda hello, x
    cmp #0
    beq done
    stx SaveX
    ;jsr $FEDE   ; console_put_char
    jsr $FFD2    ; CHROUT
    ldx SaveX
    inx
    jmp again
done:
    rts
SaveX: .byte 0
hello:
    .byte   "hello world! ", $00
 

[StephenHorn]

You can't just substitute CHROUT for console_put_char.

Per the documentation, under "Console":

Quote

Console

$FEDB: console_init - initialize console mode $FEDE: console_put_char - print character to console $FED8: console_put_image - draw image as if it was a character $FEE1: console_get_char - get character from console $FED5: console_set_paging_message - set paging message or disable paging

The console is a screen mode that allows text output and input in proportional fonts that support the usual styles. It is useful for rich text-based interfaces.

Function Name: console_init

Signature: void console_init(word x: r0, word y: r1, word width: r2, word height: r3); Purpose: Initialize console mode. Call address: $FEDB

Description: This function initializes console mode. It sets up the window (text clipping area) passed into it, clears the window and positions the cursor at the top left. All 0 arguments create a full screen console. You have to switch to graphics mode using screen_set_mode beforehand.

Function Name: console_put_char

Signature: void console_put_char(byte char: .a, bool wrapping: .c); Purpose: Print a character to the console. Call address: $FEDE

Description: This function prints a character to the console. The .C flag specifies whether text should be wrapped at character (.C=0) or word (.C=1) boundaries. In the latter case, characters will be buffered until a SPACE, CR or LF character is sent, so make sure the text that is printed always ends in one of these characters.

Note: If the bottom of the screen is reached, this function will scroll its contents up to make extra room.

With this documentation in mind, consider the following modifications:

; screen_set_mode
    lda #$80
    jsr $FF5F ; SET 320x200@256C MODE

; console_init
    ; All zeroes in r0 through r3 result in a full-screen console
    ;r0
    stz $02
    stz $03
    ;r1
    stz $04
    stz $05
    ;r2
    stz $06
    stz $07
    ;r3
    stz $08
    stz $09

    jsr $FEDB

; rest of the code
   ldx #0
again:
    lda hello, x
    cmp #0
    beq done
    stx SaveX
    sec ; Adding carry to wrap at word boundaries
    jsr $FEDE   ; console_put_char
    ;jsr $FFD2    ; CHROUT
    ldx SaveX
    inx
    jmp again
done:
    rts
SaveX: .byte 0
hello:
    .byte   "hello world! ", $00

 

Edited May 14, 2020 by StephenHorn
Comparing the two code editors.

[Craig]

OK, I will try this.  I did not realize I needed to init the console.  I figured it was already initialized.

Thanks,

Craig

[SlithyMatt]

41 minutes ago, Craig said:

 I did not realize I needed to init the console.  I figured it was already initialized.

It's not the console that needs to be initialized, but the new kernal console library.

I have created a simple print macro for ca65 that uses the legacy kernal:

.macro PRINT_STRING str_arg
   .scope
         jmp end_string
      string_begin: .byte str_arg
      end_string:
         lda #<string_begin
         sta ZP_PTR_1
         lda #>string_begin
         sta ZP_PTR_1+1
         ldx #(end_string-string_begin)
         ldy #0
      loop:
         lda (ZP_PTR_1),y
         jsr CHROUT
         iny
         dex
         bne loop
   .endscope
.endmacro

Then you can pass whatever string you want, e.g.:

PRINT_SCREEN "hello, world!"

I created another macro to print a carriage return to get to the next line:

.macro PRINT_CR
   lda #$0D
   jsr CHROUT
.endmacro