Re: [cc65] Why does this work in 128 mode but not 64 mode?

From: Payton Byrd <plbyrd1gmail.com>
Date: 2010-04-30 15:49:31
On Fri, Apr 30, 2010 at 1:08 AM, Ullrich von Bassewitz <uz@musoftware.de>wrote:

> _cbm_k_open:
>        jsr     OPEN            ; <- KERNAL call
>        ldx     #0              ; Clear high byte
>        bcs     @NotOk
>        txa
> @NotOk: rts
>


Just out of curiosity, what's the point of using X to clear the carry bit of
A?  Wouldn't this be more efficient?

_cbm_k_open:
        jsr OPEN
        bcs @NotOk
        lda #0
@NotOk: rts

The one good example of handling the error I've seen comes from the C128 PRG
and it immediately does the BCS after returning from the OPEN routine.  I'm
no ML expert by any means, but I'm wondering if this might not be
contributing to the problem.  There's no denying that oserror is NOT being
populated with the error.


-- 
Payton Byrd
<http://www.paytonbyrd.com>
<http://it.toolbox.com/blogs/paytonbyrd>

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Received on Fri Apr 30 15:50:00 2010

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