Welcome home! Let's get you a nice cozy heatsink and get you settled back in your case. Thanks to Amiga of Rochester for getting everything fixed up! #motorola#retrocomputing#68k#mac68k
Welcome to #MOVember, one asm MOV instruction each day.
The Motorola MC68000 has a BEAST of a MOV instruction.
Official assembler mnemonic: MOVE. Refreshingly clear!
You could move to and from registers and/or memory. 8-, 16-, 32- data sizes. Post increment, predecrement. Including memory-to-memory moves (Ferris Bueller soundtrack voice: Oh Yeah).
*d++ = *s++ is a single instruction in 68000.
Officially destination on the right: MOVE A7,D0 copies the A7 register to D0
Getting a weird bug deep down in the Mac initialization routines makes me regret not taking the time to make unit test for every single freaking opcode.
Yeah that would have been very time consuming.
But stepping in assembly code you don't understand looking for the moment something borks is too.
And it's probably due to a missing semicolon somewhere.
"Well I guess it's better than PASS: 0" - me, ever the optimist.
Have I told you I hate the 68000 CPU? How about making the instructions easy to decode, Motorola?
For John Mastodon's sake, even the 80x86 is simpler than that! :meow_angry_intensifies:
In love with the #68k "Address Register Indirect with Postincrement" addressing mode. Yes, I know we have every fancy thing imaginable today, but thinking about it in context, I think it's amazing.
.loop:
move.l (a0)+,(a1)+
dbra d0,.loop
Where d0 contains the number of longwords to copy. Address increment works with words and bytes as well? Love it! #assembly
Friends of #68k, I am starting to design #ubttix (unix based 32bits os) first on the pi pico and stm32l4 because thats what I have, but the clear goal is to have this run on 68k. Having two arm targets forces me to design it portable.
The beast grows. My #68k computer is getting closer to the finish line. Chewed through a lot this weekend!
Adjusted common ROM address lines, they were going over the chips and it bothered me. Plus, I'll probably be bouncing those in and out for a while until I venture to programming via a boot loader.
Wired up the many buffered address lines. I did a continuity check last night and it looks good so far. :blobsweat:
Finished the control line buffer and distributed the outputs. I used a big fat purple wire for /DTACK out of respect (or disrespect depending on whom you ask) :blobcatangel:
Finished the /IACK decoder
Wired up the GAL inputs and some of the outputs
New TODOs queued up:
Finish connecting the 68681 serial chips
Finish placing decoupling caps
Replace 7404 with open-drain 7405 variant to work properly with the /RESET line
More progress on my #68k computer. Buffers are in and placements sorted for the other chips after some scooting. Data lines are hooked up. The ATF22V10 is programmed, a simple joy that was ^^. Thanks for the tip, @gorplop !
The complexity level has reached the scary threshold, so I took some time to put together a schematic, a singular reference instead of my pile of papers... now to get it plotted on an A1 sheet... XD
Just have to say... thanks to all of the #kicad contributors who have made so many improvements over the years. The changes for 7.0 alone are excellent.
I have run into the color #68k Microprocessor User's Manual and the cover is stunning! I've been staring at that crummy black and white facsimile for years.
My #68k home brew computer is coming along nicely. I’ve decided on 512Kx16 ROM and 1Mx16 RAM, and just a 68K-era 68C681 serial chip for I/O for now. I might hook up a parallel port and the FPGA VGA interface I’m working on later. I’ve started hooking up the serial chip and preparing placements for bus buffers and transceivers. 555-based power-on reset circuit is set as well.
There is something really calming about carefully measuring and weaving hookups on the #breadboard.
Here's a #68k CPU family portrait: one of the oldest (68000) and one of the youngest (68060). I'm always surprised at how big the “Texas Cockroach” actually feels on one's hand!
Ingemar Ragnemalm first released the Sprite Animation Toolkit (SAT) in 1992. “I have always liked to make computer games,” Ingemar wrote in the SAT manual. “It has been one of my hobbies since the late 70’s. When I started using Macs, of course I wanted to make some games for it too.” After writing many games, he had...
#RetroComputing#VintageMac folks: does anyone have, or know where I can find, drivers for the Mirror Technologies “Tornado Graphics Card”?
I picked this card up from eBay the other day. It’s a 24-bit NuBus graphics card that is a rebadged version of the “MicroConversions 2124NB”. It supposedly offers NuBus acceleration, but requires a driver to operate, which I do not have.
There is a driver for the “MicroConversions 2124NB II” that is archived, but this driver doesn’t work with the Tornado.
The good news is that, even unaccelerated, it offers much faster performance in my IIfx than both my Lapis ProColorServer 8•16 II and my Macintosh Display Card 4•8. Haven’t tested to see if it works with Linux yet, though.
sprite animation toolkit (1992-1999) | dev-nonsense (dev-nonsense.com)
Ingemar Ragnemalm first released the Sprite Animation Toolkit (SAT) in 1992. “I have always liked to make computer games,” Ingemar wrote in the SAT manual. “It has been one of my hobbies since the late 70’s. When I started using Macs, of course I wanted to make some games for it too.” After writing many games, he had...