[Coco] Optimizing 6809 Assembly Code: Part 2 – Speedup Storing Data – Unrolling Loops

[Glen Hewlett]

Hi Steve,

Yes I do the same and it is a valid thing to mention as it will speed up your program if you are doing long branches and that is what this series is all about.  I just added it to Part 1 of my series.

Thanks for the tip,
Glen.

> On Sep 16, 2017, at 11:01 AM, Steve Bamford via Coco <coco at maltedmedia.com> wrote:
> 
> Yep, just checked.For long branches - 5 cycles if branch not taken, 6 cycles if taken.
> 
>      From: Simon Jonassen <simon at roust-it.dk>
> To: 'CoCoList for Color Computer Enthusiasts' <coco at maltedmedia.com> 
> Sent: Saturday, 16 September 2017, 15:40
> Subject: Re: [Coco] Optimizing 6809 Assembly Code: Part 2 – Speedup Storing Data – Unrolling Loops
> 
> Hey...
> 
> BRANCH is always 3 - (L)BRANCH varies.... 
> 
> but yes the code execution time will vary depending upon the execution of any given branch
> 
> /Simon :-)
> 
> 
> -----Oprindelig meddelelse-----
> Fra: Coco [mailto:coco-bounces at maltedmedia.com] På vegne af Steve Bamford via Coco
> Sendt: 16. september 2017 15:49
> Til: CoCoList for Color Computer Enthusiasts
> Cc: Steve Bamford
> Emne: Re: [Coco] Optimizing 6809 Assembly Code: Part 2 – Speedup Storing Data – Unrolling Loops
> 
> This is a great idea Glen! :)
> 
> I think I'm right in saying a branch not taken uses fewer cycles than a branch taken, (correct me if I'm wrong).
> 
> For this reason where there's a fork in the program flow I always test for the least likely outcome rather than the most likely, if that makes sense?
> Steve.
> 
> 
>       From: Glen Hewlett <glen.hewlett at sympatico.ca>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com> 
> Sent: Saturday, 16 September 2017, 3:44
> Subject: [Coco] Optimizing 6809 Assembly Code: Part 2 – Speedup Storing Data – Unrolling Loops
>   
> Hi Again,
> 
> I just posted Part 2 of my series of blogs about optimizing 6809 assembly language programs.
> 
> https://nowhereman999.wordpress.com/2017/09/15/optimizing-6809-assembly-code-part-2-speedup-storing-data-unrolling-loops/ <https://nowhereman999.wordpress.com/2017/09/15/optimizing-6809-assembly-code-part-2-speedup-storing-data-unrolling-loops/>
> 
> Cheers,
> Glen
> 
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