Search found 177 matches
- Mon Oct 07, 2013 12:32 pm
- Forum: Dragon General
- Topic: copyrights on old ROMs ?
- Replies: 4
- Views: 2210
Re: copyrights on old ROMs ?
I think the rumours 20 or so years ago were that the copyright passed to Prudential plc however I've no idea whether or not that holds any truth or what the current situation may be. It's difficult to imagine that anyone at Prudential plc would have the slightest idea about such an old low value ass...
- Sun Oct 06, 2013 9:44 pm
- Forum: Dragon General
- Topic: Dragon emulator written in Python ???
- Replies: 106
- Views: 83899
Re: Dragon emulator written in Python ???
That's a little to hight for me, at the moment. e.g. what is "mapmode0" ? The map mode basically controls the configuration of RAM and ROM for a system using an MC6883 (SAM). You can read full details about how it decodes addresses in the data sheet: http://images.ihscontent.net/vipimages/VipMaster...
- Sun Oct 06, 2013 5:04 pm
- Forum: Uploads
- Topic: Rebound from Your Computer magazine
- Replies: 3
- Views: 3278
Re: Rebound from Your Computer magazine
I suppose "-(A1=31)" will evaluate to 1 when A1 reaches 31 and 0 otherwise.
So it makes the right-hand border draw at X=63 instead of X=62 and therefore outlines the screen edge a little more neatly with the published expression.
So it makes the right-hand border draw at X=63 instead of X=62 and therefore outlines the screen edge a little more neatly with the published expression.
- Sun Oct 06, 2013 2:49 pm
- Forum: Dragon General
- Topic: Dragon emulator written in Python ???
- Replies: 106
- Views: 83899
Re: Dragon emulator written in Python ???
This is what to do at reset:
- Set mapmode0 and reinstate the mapmode0 ROM
- Set DP to #0
- Set the I and F flags in CC to mask interrupts
- Load PC from $FFFE
- Sun Oct 06, 2013 3:43 am
- Forum: Dragon General
- Topic: Dragon emulator written in Python ???
- Replies: 106
- Views: 83899
Re: Dragon emulator written in Python ???
Not really, no. The ROM loads S with a value after detecting how much RAM is installed.jedie wrote:So i set the initial stack pointer to $7E36, is that right?
It should wrap around between 0 and $FFFF just like other registers.
- Sat Oct 05, 2013 2:53 am
- Forum: Dragon General
- Topic: Comparison of Dragon Assemblers?
- Replies: 14
- Views: 7221
Re: Comparison of Dragon Assemblers?
I always had the impression that the DREAM family was the most popular or best regarded assembler - not sure if any reviews or stats ever provided the basis for this belief. It was originally licensed by Dragon Data so probably inherited some status that way.
- Wed Oct 02, 2013 6:48 pm
- Forum: Hints and Tips
- Topic: Howto try small machine code programs in BASIC ?
- Replies: 53
- Views: 22819
Re: Howto try small machine code programs in BASIC ?
If you're getting FULL when trying to start DREAM then you haven't allocated any/enough memory with CLEAR. The built-in editor is pretty easy to use IMO; certainly much easier than BASIC. There's not much more you need to know to get started and most of it is on page 27 of the manual. BREAK then A t...
- Wed Oct 02, 2013 11:47 am
- Forum: Hints and Tips
- Topic: Howto try small machine code programs in BASIC ?
- Replies: 53
- Views: 22819
Re: Howto try small machine code programs in BASIC ?
Are you doing all your assembly by hand? You'd surely find it easier to use an assembler like DREAM. It's straightforward to launch (execute) the assembled program within DREAM too. If you have ALLDREAM then it comes with the DREAMBUG debugger built-in, which isn't especially easy to use but can be ...
- Tue Oct 01, 2013 11:02 pm
- Forum: Hints and Tips
- Topic: Howto try small machine code programs in BASIC ?
- Replies: 53
- Views: 22819
Re: Howto try small machine code programs in BASIC ?
Here are some options:jedie wrote:But can i print the value (in this case $58 == 88) of accumulator A to screen?
- Use a debugger
- Make a simple routine that outputs the hex value using two ascii characters
- JSR 38266 outputs the decimal value of D register
- Tue Oct 01, 2013 12:41 am
- Forum: Hints and Tips
- Topic: Howto try small machine code programs in BASIC ?
- Replies: 53
- Views: 22819
Re: Howto try small machine code programs in BASIC ?
I wouldn't really recommend using DEF USR & VARPTR unless you really do want to "pass values to and from Basic" and even then it's a bit of a headache. Having a BASIC loader is unnecessary unless you're using both BASIC and machine language together and especially want to have a single file (a BASIC...