Printing text on screen using ASM

[20questions]

Still somewhat new to 6502 and i was wondering how to print text on screen. I read in the Programmers manual to use JSR $FFd2 to do so.
however I'm not so sure

This was the code i had printed:
LDA $68
JSR $FFD2
LDA $69
JSR $FFD2
LDA $65
JSR $FFD2
LDA $68
JSR $FFd2
(DEAD)

I didn't see an ASM equivalent to print so i'm playing this by ear...poorly

[srowe]

You can either re-use the BASIC routine PRTSTR ($CB1E) to print a string terminated by a NUL

Code: Select all

prtstr = $cb1e

	lda #<text
	ldy #>text
	jsr prtstr

text	.byt	"hello, world",$0d,$00

or just implementing something similar from scratch.

[20questions]

You can either re-use the BASIC routine PRTSTR ($CB1E) to print a string terminated by a NUL

Code: Select all

prtstr = $cb1e

	lda #<text
	ldy #>text
	jsr prtstr

text	.byt	"hello, world",$0d,$00

or just implementing something similar from scratch.

how do i do this in Vicmon? it doesn't allow the use of labels

[Mike]

how do i do this in Vicmon? it doesn't allow the use of labels

In the thread "A sample programming session in VICMON" I give several examples, where strings are PRINTed with JSR $FFD2.

VICMON only provides a non-symbolic direct assembler. You either need to adopt the method(s) I lined out in said thread, or otherwise keep aside a piece of paper where you write down all relevant addresses and character codes in hexadecimal to insert them as instruction operands as necessary.

BTW, your first example in this thread here won't work as intended. You wrongly use zeropage addressing to read the values contained in addresses $65, $68 and $69 into A, which by themselves very likely will *not* contain $65, $68 and $69 as values. You should be using immediate addressing instead, signified by #$65, #$68 and #$69 as operands (note the hashes!), which truly load the values $65, $68 and $69 into A.