Yes, I'm still harping on. Sorry :-)
Edwin wrote:
> Like the Idea. So I looked a bit better at LDIR in ROM too.
>
> LDIR is made up of 5 M-cycles:
> 4,4,3,5,5 for standard LDIR = 21T
> 4,4,3+1,5,5+2 LDIR in RAM with RAM contemption = 24T
> 4+4,4+4,3+5,5,5+6 LDIR in RAM with Display contemption =
Please disregard last message: I'm being stupid.
I wrote:
> See I disagree about this...
>
> Won't it be
>
> [4]
> [4]
> Loop around:
> {3},{1 WAIT} 4 cycles
> {5},[3 of 5] 8 cycles
> [2 of 5],[2 of 4] 4 cycles
> [2 of 4], {2 WAIT} 4 cycles
Ignore me. I've missed a [4] out.
Geoff
> Edwin,
> I have another question: On Spectrum, it was the basic asm knowledge that
JR
> is shorter but slower than JP. But how does it work on Sam? I assume
> (without any exact computation) that due to the contention, JR is probably
> faster than JP in general cases. Am I right? (I consider con
Message -
From: "Edwin Blink" <[EMAIL PROTECTED]>
To:
Sent: Thursday, February 03, 2005 10:22 PM
Subject: Re: Fastest memory transfer (on Sam)
From: Geoff Winkless <[EMAIL PROTECTED]>
Please understand that I'm not trying to be awkward; I just don't
com
From: Geoff Winkless <[EMAIL PROTECTED]>
> Please understand that I'm not trying to be awkward; I just don't
comprehend
> the logic.
No prob. I hadn't looked this close on ROM Display contention before so it
is interesting to look into and discuss it, also a reminder to get on with a
Z80
T-State
Edwin Blink wrote:
> From: Geoff Winkless <[EMAIL PROTECTED]>
>
>> Without wishing to appear stupid (yeah, I know, too late, haha), I'm
>> still not clear why that's a memory access.
>
> It's not. The delay is added there for convenience. But in fact it
> will delay the next
> opcode fetch (unles
On Wed, 2005-02-02 at 19:11, Edwin Blink wrote:
> I'd prefer a redesigned ASIC (with a few other fixes). I see little
> advantage in
> having a accelerator board Because the extra power is needed in handling
> video memory. An accelerator board would have to wait just like the Z80
> does.
A simpl
I can't remember if thats the case with Colins device he showed recently?Edwin Blink <[EMAIL PROTECTED]> wrote:
From: Geoff Winkless <[EMAIL PROTECTED]>> Without wishing to appear stupid (yeah, I know, too late, haha), I'm still> not clear why that's a memory access.It's not. The delay is added the
From: Geoff Winkless <[EMAIL PROTECTED]>
> Without wishing to appear stupid (yeah, I know, too late, haha), I'm still
> not clear why that's a memory access.
It's not. The delay is added there for convenience. But in fact it will
delay the next
opcode fetch (unless it is in rom but read below).
Edwin Blink wrote:
>> Incidentally, what are the 5 cycles for an LDIR?
>
> It uses the same technique as used by relative jumps to add a value
> of -2 to PC.
Without wishing to appear stupid (yeah, I know, too late, haha), I'm still
not clear why that's a memory access.
I've found a more helpf
> Incidentally, what are the 5 cycles for an LDIR?
It uses the same technique as used by relative jumps to add a value of -2
to PC.
>so is it really the case that the z80 reads the (erroneous) next
instruction before doing PC-=2 (as
> one source on the web suggested)?
I think that suggestion c
Edwin Blink wrote:
> From: Geoff Winkless <[EMAIL PROTECTED]>
>
>> Trying to think this through...
>
> Like the Idea. So I looked a bit better at LDIR in ROM too.
>
> LDIR is made up of 5 M-cycles:
> 4,4,3,5,5 for standard LDIR = 21T
> 4,4,3+1,5,5+2 LDIR in RAM with RAM contemption = 24T
> 4+4,4
- Original Message -
From: Aley Keprt <[EMAIL PROTECTED]>
>I originally though it's number of T-states, but POP must take at least
12T,
>definitely not 4T.
Obviously a typing mistake :-)
here are some more timings for PUSH/POP:
PUSH qq (5,3,3) Standard =11Ts
PUSH qq (5+3,3+1,3+1) RAM co
esday, February 01, 2005 1:48 PM
To: sam-users@nvg.ntnu.no
Subject: Re: Fastest memory transfer (on Sam)
>I already tried many LDI's and PUSH/POP system on my own, but
>unfortunately the process of changing SP makes PUSH/POP slower than
>sequence of LDI's.
The fastest scrollleft
01, 2005 1:48 PM
To: sam-users@nvg.ntnu.no
Subject: Re: Fastest memory transfer (on Sam)
>I already tried many LDI's and PUSH/POP system on my own, but
>unfortunately the process of changing SP makes PUSH/POP slower than
>sequence of LDI's.
The fastest scrollleft code I could
From: Geoff Winkless <[EMAIL PROTECTED]>
> Trying to think this through...
Like the Idea. So I looked a bit better at LDIR in ROM too.
LDIR is made up of 5 M-cycles:
4,4,3,5,5 for standard LDIR = 21T
4,4,3+1,5,5+2 LDIR in RAM with RAM contemption = 24T
4+4,4+4,3+5,5,5+6 LDIR in RAM with Display
Edwin Blink wrote:
The fastest scrollleft code I could think of is the folowing code snippet
which should be repeated 9*height times and
It's best to write a routine to generate it runtime and fill in the proper
SP values.
[snip]
It's 20% faster and takes 29% less space then LDI's.
BTW Th
>I already tried many LDI's and PUSH/POP system on my own, but unfortunately
>the process of changing SP makes PUSH/POP slower than sequence of LDI's.
The fastest scrollleft code I could think of is the folowing code snippet
which should be repeated 9*height times and
It's best to write a routine
hat I wonder how it will look on the real
machine. (I will testlater.) ;-)Aley-Original
Message-From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
On Behalf Of Simon OwenSent: Monday, January 31, 2005 4:15 AMTo:
sam-users@nvg.ntnu.noSubject: RE: Fastest memory transfer (on
Sam)Aley Keprt
onder how it will look on the real machine. (I will test
later.) ;-)
Aley
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Simon Owen
Sent: Monday, January 31, 2005 4:15 AM
To: sam-users@nvg.ntnu.no
Subject: RE: Fastest memory transfer (on Sam)
Aley Keprt
ay, January 30, 2005 2:44 PM
To: sam-users@nvg.ntnu.no
Subject: Re: Fastest memory transfer (on Sam)
I need to move (video) memory on Sam, what's the fastest routine? I expect
it must utilize push & pop instructions, since they take just 10T to move a
byte, but I am unsure what is exact lo
Aley Keprt wrote:
> I need to move (video) memory on Sam, what's the fastest routine?
Despite its unfinished state, the SimCoupe debugger can be used to time
blocks of code. Whenever you enter the debugger the T-diff value in the
bottom right of the display shows the number of _real_ tstates that
I need to move (video) memory on Sam, what's the fastest routine? I expect
it must utilize push & pop instructions, since they take just 10T to move a
byte, but I am unsure what is exact look of the whole routine. Please can
somebody help me?
There is not a single fastest routine for everything. T
I need to move (video) memory on Sam, what's the fastest routine? I expect
it must utilize push & pop instructions, since they take just 10T to move a
byte, but I am unsure what is exact look of the whole routine. Please can
somebody help me?
---
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