Search found 463 matches

by ob1
Mon Feb 08, 2021 2:27 pm
Forum: Super 32X
Topic: 32X Slave SH2 BIOS disassembly
Replies: 0
Views: 74143

32X Slave SH2 BIOS disassembly

Yo guys. Here is a disassembly of the Slave SH2 BIOS. I went a bit further than for the master (13 years ago !!!) and I finally got the frame buffer read (it's for the Sega CD32X, stupid!). INITIAL_SP equ $0603F800 dc.l start dc.l INITIAL_SP dc.l start dc.l INITIAL_SP dc.l fail dc.l 0 dc.l fail dc.l...
by ob1
Sat Feb 06, 2021 1:19 pm
Forum: Super 32X
Topic: DMA DEI
Replies: 6
Views: 9345

Re: DMA DEI

- is DEI implemented in any emulator ? Regarding Gens 2.15.4, it looks like it is not implemented. In sh2a.asm, line 5736 : ALIGN32 ; void FASTCALL SH2_DMA0_Request(SH2_CONTEXT *sh2, UINT8 state) ; ecx = context pointer ; edx = request line for external (0 = off, !0 = on) ; ; RETURN: ; nothing ... ...
by ob1
Sat Feb 06, 2021 1:16 pm
Forum: Super 32X
Topic: DMA DEI
Replies: 6
Views: 9345

DMA DEI

Hello fellows. The Hitachi SH-7604 Hardware Manual defines the IE bit (bit #2) in CHCR register (§9.2.4) as : Interrupt Enable Bit (IE): Determines whether or not to request a CPU interrupt at the end of a DMA transfer. When the IE bit is set to 1, an interrupt (DEI) request is setnt to the CPU when...
by ob1
Sat Feb 06, 2021 11:00 am
Forum: Super 32X
Topic: DMA DREQ delay
Replies: 1
Views: 4934

DMA DREQ delay

Once upon a time, Chilly Willy said : When doing 68K to 32X DMA via the FIFO in the 32X, it has a tendency to lose data randomly. Specifically, the DREQ fails to trigger the DMA under unknown circumstances, which means the SH2 DMA stops. If you are checking the FIFO full flags, it will "stick" at fu...
by ob1
Thu Feb 04, 2021 1:48 pm
Forum: Demos
Topic: Release "Space flies attack" for Sega Genesis / MD
Replies: 11
Views: 15975

Re: InDev Space flies attack for Sega Genesis / MD

I'm a simple man.
I see more than 64 colors on screen, I thumb-up.

Good luck to you ;)
by ob1
Mon Jan 25, 2021 8:00 am
Forum: SGDK
Topic: Writing multiple VSRAM values per scanline
Replies: 3
Views: 6348

Re: Writing multiple VSRAM values per scanline

I'm not sure that I understood everything,
but I have played a few times with HInt, and I must say this rock stable image is great.
Bravo for this piece of work.
by ob1
Wed Jan 20, 2021 9:52 am
Forum: Megadrive/Genesis
Topic: 68K Memory access
Replies: 9
Views: 11193

Re: 68K Memory access

by ob1
Wed Jan 20, 2021 9:48 am
Forum: Megadrive/Genesis
Topic: 68K Memory access
Replies: 9
Views: 11193

Re: 68K Memory access

I'm not sure I correctly understood your question, but there is this block diagram that I like very much : https://gamesx.com/wiki/lib/exe/fetch.php?media=schematics:genesis_block_diagram.png (this diagram states that the address bus is 16 bits, but I'm pretty sure it is 24 bits). Here, you can see ...
by ob1
Mon Jan 18, 2021 4:42 pm
Forum: Demos
Topic: ELLENICA: An update on my RPGAdventure (2021)
Replies: 2
Views: 5206

Re: ELLENICA: An update on my RPGAdventure (2021)

Wow! Impressive AND original.
I'll keep an eye on it.
Kudos to you and good luck ^^

Olivier
by ob1
Tue Nov 24, 2020 12:57 pm
Forum: Announcement
Topic: Spritesmind is back
Replies: 6
Views: 26775

Re: Spritesmind is back

Thank you so much Kaneda for ensuring this great forum is still up and running.
by ob1
Mon Nov 23, 2020 9:10 pm
Forum: Super 32X
Topic: 32X memory type
Replies: 5
Views: 10262

Re: 32X memory type

I hate to "raise topics from their grave", but I really hope you dear reader will find some resources of interest in this post. So, regarding memory type, here are the Bus State Controler settings made in BIOS : value_offset_348h: DC.L $A55A0001 ; BCR1 Bus Control Register 1 (FFFF FFE0) Master, Big-...
by ob1
Tue Dec 24, 2019 9:11 am
Forum: Demos
Topic: Mode 7 demo for Genesis/MD
Replies: 63
Views: 194261

Re: Mode 7 demo for Genesis/MD

#SlowClap

Bravo !
A hell of an update !
by ob1
Thu May 10, 2018 2:07 pm
Forum: Super 32X
Topic: Glide 32X
Replies: 8
Views: 16649

Re: Glide 32X

Great answer and lots of useful informations, as usual. Thank you very much Chilly ^^
by ob1
Wed May 09, 2018 6:01 pm
Forum: Super 32X
Topic: Glide 32X
Replies: 8
Views: 16649

Re: Glide 32X

OR,
I could use 32X Auto Fill and climb from 8 to 68 triangles per frame.
Still a pity, but ...
by ob1
Wed May 09, 2018 9:16 am
Forum: Super 32X
Topic: Glide 32X
Replies: 8
Views: 16649

Re: Glide 32X

I've stated fixed-decimal, but only the representation is decimal (10 bits for the integer part, 5 bits for the "fractional" part).
My implementation uses something between Digital Differential Analyzer and Bresenham's line algorithm.
PS : didn't know of GDM. Thx.