What`s the difference between a JP and a JR, I don`t even mean
in T-States, but what varies between the way they work. If you`s
don`t mind me asking ?
Cal...
`Geoff Winkless [EMAIL PROTECTED] wrote:`Geoff Winkless wrote:
Anyway, something like:
[snip]
Sorry, it's been a while and I was tired
What`s the difference between a JP and a JR, I don`t even mean
in T-States, but what varies between the way they work. If you`s
don`t mind me asking ?
JP reads in two bytes more to use as an address to jump to.
JR reads in only one more byte, to use as an offset from the current address
to
commands,
some dont, its not always that hard to alter. The grabbing is a similar MC
routine.
Adrian
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Calvin Allett
Sent: 16 May 2007 02:46
To: Adrian
Subject: RE: MC Interrupts
`Did someone call? ;) Yes
Ah sweet :) soz for delay, just spent 45 mins typing another reply !
Handy command then JR
Colin Piggot [EMAIL PROTECTED] wrote: What`s the difference between a JP
and a JR, I don`t even mean
in T-States, but what varies between the way they work. If you`s
don`t mind me asking ?
JP reads
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Calvin Allett
Sent: 16 May 2007 02:46
To: Adrian
Subject: RE: MC Interrupts
`Did someone call? ;) Yes it was the early issues, it was issues 1-5 i think,
` i was only talking to colin this evening about that, now ive moved i
Thanks :) I`ve been reading the 1995 posts to the mailing list these
past few days, and it`s amazing how much I`m picking up from
those old old posts, so I`ve seen it mentioned that they run at around
the same speed on SAM, am I remembering right that it depends
where in screen the raster is when
On 17 May 2007, at 23:24, Calvin Allett wrote:
Andrew Collier [EMAIL PROTECTED] wrote:
Because of the Sam's memory timings, using JR is usually as fast (or
slightly faster than) using JP. That may change with Mayhem
accelerator!
Thanks :) I`ve been reading the 1995 posts to the mailing
So the SAMs z80 really is actually slowed down quite considerably, I hadn`t
realised how much :(
Thanks for the details :)
Andrew Collier [EMAIL PROTECTED] wrote: On 17 May 2007, at 23:24, Calvin
Allett wrote:
Andrew Collier wrote:
Because of the Sam's memory timings, using JR is usually
Of Calvin Allett
Sent: 16 May 2007 02:46
To: Adrian
Subject: RE: MC Interrupts
`Did someone call? ;) Yes it was the early issues, it was issues 1-5 i
think,
` i was only talking to colin this evening about that, now ive moved i
` really need to get on with finishing it, although i lost all my code
Geoff Winkless wrote:
Anyway, something like:
[snip]
Sorry, it's been a while and I was tired (!!), those local JP's should all
(of course) be JR's!
Geoff
__
This email has been scanned by the MessageLabs Email Security
Calvin Allett wrote:
so would it seem feasable to be able to alter the routine
with a flag, so that it jumps straight back every other frame
and only draws the other frames?
Assuming you don't need to worry about redrawing them if they haven't moved
you could simply add your own interrupt
Calvin Allett wrote:
I`ve been wondering this before, in relation to the Mayhem
accelerator, as if wanting to write a game to run at 20Mhz
(about four times normal speed with uncontended RAM?)
then if I`d be able to run an intterupt music player, but have
the player altered to only play the
Calvin Allett wrote:
so would it seem feasable to be able to alter the routine
with a flag, so that it jumps straight back every other frame
and only draws the other frames?
`Assuming you don't need to worry about redrawing them if they haven't
`moved
`you could simply add your own
Calvin Allett wrote:
I`ve been wondering this before, in relation to the Mayhem
accelerator, as if wanting to write a game to run at 20Mhz
(about four times normal speed with uncontended RAM?)
then if I`d be able to run an intterupt music player, but have
the player altered to only play the
Quoting Colin Piggot [EMAIL PROTECTED]:
Interrupts aren't affected by the speed of the machine.
The ASIC generates the frame interrupt every 50th of a second, it's all tied
right into the video timings. So things like music players, or any frame
interrupt (or line interrupt) routines don't
Quoting Calvin Allett [EMAIL PROTECTED]:
I used to love these demo`s, and the converted games, as I still
usually prefer AY music over The Sound Machine, or E-tracker, although
some SAM tunes blow the AY away :) I was thinking it might be easier
to get someone to do a tune or two for games, if
Quoting Calvin Allett [EMAIL PROTECTED]:
I`ve come across a little routine on an old disk magazine that
provides four 8*8 pixel masked `sprites` via a MC interrupt routine,
it seems pretty fast, and am wondering about trying to use it,
however I`m wondering if it`s possible to alter an
I still need to catch up on the later issue`s, and the earlier ones... I`d
forgot there was such an article, but I`d heard, one of the early ones I think
:)
[EMAIL PROTECTED] wrote: Quoting Calvin Allett :
I`ve come across a little routine on an old disk magazine that
provides four 8*8
Quoting Calvin Allett [EMAIL PROTECTED]:
I still need to catch up on the later issue`s, and the earlier
ones... I`d forgot there was such an article, but I`d heard, one of
the early ones I think :)
I've got a site to work on tonight, otherwise I'd be dipping in my issues to
look for you :(
no probs mate, I`m not exactly gonna be able to do anything with any MC code
yet anyhow, and I know your busy :) I do love looking through the issue`s I
have, it always eggs me on to do more coding, but I need to get the early
issue`s especially for the (sounding great) articles :D
[EMAIL
`Did someone call? ;) Yes it was the early issues, it was issues 1-5 i think,
` i was only talking to colin this evening about that, now ive moved i
` really need to get on with finishing it, although i lost all my code
` when i lost the sam harddrive. Ive now got a sam in a can and have
` some
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