Help with VPrintf

[Nightfox]

Hi I'm trying to work out how to use VPrintf.

Here's my program and I want it to output 45 but instead it is outputting 133659

****
Include exec/types.i
include exec/libraries.i
Include exec/exec_lib.i
include dos/dos_lib.i
Include macros.i

start:
lea dos_name(pc),a1
CALLEXEC OpenLibrary
move.l d0,dosbase
beq.s exit

print_text:
move.l #format_text,d1
move.l #text,d2
CALLSYS VPrintf,dosbase

exit:
move.l dosbase,a1
CALLEXEC CloseLibrary
rts

dos_name:
dc.b 'dos.library',0

dosbase:
ds.l

format_text:
dc.b '%1d',0

text:
dc.b '45',0

[Nightfox]

Ugh my code In the post lost its formatting.

[matthey]

Originally Posted by sacredbanana

Hi I'm trying to work out how to use VPrintf.

Here's my program and I want it to output 45 but instead it is outputting 133659

Are you sure it is not 13365 that it is outputting? The ASCII for '4' = $34 and '5' = $35 so consecutively would be $3435=13365. If that was not enough of a hint, try changing the following.

text:
   dc.b '45',0

to

text:
   dc.l 45

You might want a new name for that text label if I'm right though .

[Nightfox]

Thank you yes there was a typo in what it output. I understand now that it is actually outputting the decimal values of the ascii for each character in the string. Your hint outputs a 0. I'm still confused as to how I can fix this... and I recently graduated with a degree in computer science haha. This is my first time with assembly.

[matthey]

Originally Posted by sacredbanana

Thank you yes there was a typo in what it output. I understand now that it is actually outputting the decimal values of the ascii for each character in the string. Your hint outputs a 0. I'm still confused as to how I can fix this... and I recently graduated with a degree in computer science haha. This is my first time with assembly.

Ok, try the following.

text:
   dc.w 45,0

Your "%ld" looks like a "%1d" which may be interpreted as "%d". The data being pointed to is a long though.

[Thorham]

Originally Posted by sacredbanana

Ugh my code In the post lost its formatting.

Put your code between code tags.

<code>
bla
bla
</code>

Just change <> to [].

[Nightfox]

I tried that and it wouldn't work and I was pulling my hair out and then I thought maybe the text needs aligning... so I wrote even above the text label and voila it works! Thanks for your help

[alkis]

Also it won't work at all if you pass a really long parameter on cli (~50 chars)
and it will probably crash cause exit shouldn't close the library (cause the first reason it's at exit was that it couldn't open the library).

PS: The reason that it won't work is you forgot to specify contents of d0 and upon entry a0 points to the cli parameter string and d0 holds the length of that.