2008 06:46
To: sam-users@nvg.ntnu.no
Subject: Re: Short, short questions
I thought the idea of mode2 was you could have different vectors for
different devices connected well this throws a spanner in the works. But
then again is there any hardware for the SAM that uses them? I think it
must
have
Sent: 21 May 2008 06:46
To: sam-users@nvg.ntnu.no
Subject: Re: Short, short questions
I thought the idea of mode2 was you could have different vectors for
different devices connected well this throws a spanner in the works. But
then again is there any hardware for the SAM that uses them? I
Adrian Brown wrote:
Ok, i haven't read all the posts on this, but why not stick the code in
LMPR and use IM1 - saves having the table of vectors.
That's my favoured approach too.
** UIP Sam Port 4100+ lines of z80 and climbing
Woo! It's so tantilisingly close!
David Brant wrote:
But then
Has to be said the first thing my code does is page itself into LMPR addr 0 and
sit there :)
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Geoff Winkless
Sent: 21 May 2008 14:46
To: Adrian
Subject: RE: Short, short questions
I have to admit I
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
On Behalf Of David Brant
Sent: 21 May 2008 06:46
To: sam-users@nvg.ntnu.no
Subject: Re: Short, short questions
I thought the idea of mode2 was you could have different vectors for
different devices
the table of vectors.
Adrian
** UIP Sam Port 4100+ lines of z80 and climbing
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
On Behalf Of David Brant
Sent: 21 May 2008 06:46
To: sam-users@nvg.ntnu.no
Subject: Re: Short, short questions
I thought
Really it was related to my first question - I was considering the
plausability of moving my data table to be positioned around address
zero when I wrote the post. And obviously a table that reaches 2kb in
either direction from address 0 covers address 0x0038.
Tests last night with an older,
Andrew Collier wrote:
If I used IM1 this would require that either, a) the screen goes in
sections A
and B, and the interrupt routine is actuially visible in pixels - or b)
the
moveable window goes in sections A and B, and I have to duplicate the
interrupt routine in nearly every page of
On Wed, 21 May 2008 15:29:28 +0100, Colin Piggot [EMAIL PROTECTED]
wrote:
Andrew Collier wrote:
If I used IM1 this would require that either, a) the screen goes in
sections A
and B, and the interrupt routine is actuially visible in pixels - or b)
the
moveable window goes in sections A and B,
On Wed, May 21, 2008 at 03:16:07PM +0100, Thomas Harte wrote:
If you interrupt routine is small, could you not also just switch off
the first one or two scanlines of your display, and even grab a few
extra cycles out as a result? Or can you not enable and disable the
display per scanline?
Hi,
Literally anything? On many of the machines I have written emulators
for, most things are usually completely changeable but some things are
loaded internally — especially on any machine that has a variable
screen start address.
Also, one further question: am I right to think that the Sam has no
Thomas Harte wrote:
Literally anything? On many of the machines I have written emulators
for, most things are usually completely changeable but some things are
loaded internally — especially on any machine that has a variable
screen start address.
Not literally anything, you can change the
Hi,
Well - at least, any of the things you can ever change, yes! screen on/off,
border colour, palette, screen mode, ram page, etc.
Early versions of SimCoupe didn't support these changes better than once per
line. I remember Allan (or was it Simon?) telling me he had never realised
that the
On Wed, 21 May 2008 17:09:32 +0100, Andrew Collier
[EMAIL PROTECTED] wrote:
Correct. Always non-interlaced (despite various examples on Fred of
flickery pictures which purported otherwise).
While (on a TV with 576 visible lines) you won't be able to get a 192 line
output device to output
But Sim Coupe duplicates all known characteristics of the real
hardware now, right?
I was actually involved in writing emualtors as early as 1998, and
most of the early ones were horrible. Pretty much anything by Marat
Fayzulin or derived from his source still is — they're usually run
the CPU for
On Wed, May 21, 2008 at 05:28:58PM +0100, Thomas Harte wrote:
But Sim Coupe duplicates all known characteristics of the real
hardware now, right?
All the ones that I know about, certainly. Even the little ASIC quirks like
single-pixel vertical lines in the border (this is something Simon Cooke
I'm about to finish my lunch break, sorry if I sound slightly short...
1) is there any pattern or logic to the values placed on the bus
during interrupts? I guess an equivalent question is: what realistic
options do I have on the Sam for catching and processing interrupts?
2) are there any
On Tue, May 20, 2008 at 02:03:57PM +0100, Thomas Harte wrote:
I'm about to finish my lunch break, sorry if I sound slightly short...
1) is there any pattern or logic to the values placed on the bus
during interrupts? I guess an equivalent question is: what realistic
options do I have on the
On Tue, May 20, 2008 at 03:22:54PM +0100, Andrew Collier wrote:
correction:
ld a,h 4
sla l 8
rla4
add table/256 8
ld h,a 4
= 28
You can also shave a little more time if you're willing to rearrange the table:
Instead of word pairs (low
While thinking about it during the afternoon, I have decided that
since this table is absolutely fundamental to my program (it's part of
the table based 2.8x2.8 multiply), I'm just going to centre it on
address 0. Then I can cut the ld bc and the add hl, bc. I'm happy to
rearrange my
On Tue, May 20, 2008 at 07:20:48PM +0100, Thomas Harte wrote:
Obviously the second is faster — but I'm curious about your cycle
counts. All the z80 documentation I have lists add hl, ss as 11 t-
states. Why have you turned that into 16?
By mistake :)
I'm working from google, and misread
for the table would be 16384 (use SET 6,H), 8192
(SET 5,H), 4096 (SET 4,H) or 0 (you don't need the first SET instruction
at all)
Edwin
- Original Message -
From: Thomas Harte [EMAIL PROTECTED]
To: sam-users@nvg.ntnu.no
Sent: Tuesday, May 20, 2008 3:03 PM
Subject: Short, short
Subject: Re: Short, short questions
The usual strategies are to use mode 1, or to use mode 2 with a 257-byte
table all
containing the same byte.
the first SET
instruction at all)
Edwin
- Original Message - From: Thomas Harte [EMAIL PROTECTED]
To: sam-users@nvg.ntnu.no
Sent: Tuesday, May 20, 2008 3:03 PM
Subject: Short, short questions
I'm about to finish my lunch break, sorry if I sound slightly
short...
1) is there any
From: Thomas Harte
Surely set would only work if I had an unsigned offset from the beginning
of a table? I'm using a signed offset from the middle of a table.
it works the same as ADD HL,HL ADD HL,BC the difference is
you store the table entries LSB,MSB so you need the ADD HL,HL
First you
Boy Do I feel silly I missed that ADD HL,BC.
Edwin
- Original Message -
From: Thomas Harte [EMAIL PROTECTED]
To: sam-users@nvg.ntnu.no
Sent: Tuesday, May 20, 2008 9:53 PM
Subject: Re: Short, short questions
Surely set would only work if I had an unsigned offset from
ina,(status.int)
.
.
ei
ret
- Original Message - From: Andrew Collier [EMAIL PROTECTED]
To: sam-users@nvg.ntnu.no
Sent: Tuesday, May 20, 2008 3:22 PM
Subject: Re: Short, short questions
: Re: Short, short questions
Hi,
I'm sceptical about this claim. I've never heard anybody say that the
vector formed is big-endian - it's just you don't know the byte offset
from which the interrupt vector will be fetched. (As Edwin says, it is
usually 255 - which is odd so your 1-aligned
: David Brant [EMAIL PROTECTED]
To: sam-users@nvg.ntnu.no
Sent: Tuesday, May 20, 2008 10:49 PM
Subject: Re: Short, short questions
This was based on info from a book called z-80 Workshop manual by E.A
Parr. The I register gives the high part of the table and the hardware
gives the low part
Subject: Re: Short, short questions
This was based on info from a book called z-80 Workshop manual by
E.A Parr. The I register gives the high part of the table and the
hardware gives the low part to the table then takes that word for
the service routine. So if you start from one byte before
AM
Subject: Re: Short, short questions
I've just been looking at my books. Although I can't find the bit that
said about swapping to high,low but I'm sure that I did read it somewhere.
It does say that the device only gives the bits 1-7 and bit 0 is always 0
giving 128 possible addresses.
Dave
.
After a little test and using old brain this is wrong.
Dave
- Original Message -
From: Edwin Blink [EMAIL PROTECTED]
To: sam-users@nvg.ntnu.no
Sent: Wednesday, May 21, 2008 5:34 AM
Subject: Re: Short, short questions
All 8 bits are used for LSB of the vector. The part where bit 0
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