Search found 354 matches

by sdm
Tue Aug 09, 2022 3:15 pm
Forum: Other Retro Dev
Topic: Sega Mega Drive Clone - Region Switch Mod
Replies: 7
Views: 745

Re: Sega Mega Drive Clone - Region Switch Mod

Thanks. So it is similar.
In the first clone after loading the game with Genesis, I had a message about an incompatible game region, while in this console I only have a black screen.
by sdm
Tue Aug 09, 2022 8:01 am
Forum: Other Retro Dev
Topic: Sega Mega Drive Clone - Region Switch Mod
Replies: 7
Views: 745

Re: Sega Mega Drive Clone - Region Switch Mod

I have another SMD clone. I can see 5 jumpers: J1, J3 and a set of three jumpers next to the large heat sink. I understand that the console is set to 50hz by default but with the USA / NTSC region?

As in the first case, Aladdin PAL does not work on it.
by sdm
Mon Jul 25, 2022 12:49 pm
Forum: Other Retro Dev
Topic: Sega Mega Drive Clone - Region Switch Mod
Replies: 7
Views: 745

Re: Sega Mega Drive Clone - Region Switch Mod

Thanks. I'll check these jumpers.
by sdm
Sun Jul 24, 2022 12:22 pm
Forum: Other Retro Dev
Topic: Sega Mega Drive Clone - Region Switch Mod
Replies: 7
Views: 745

Sega Mega Drive Clone - Region Switch Mod

I have a Sega Mega Drive "MEGAGAME" clone. I wonder if it is possible to install a PAL / NTSC switch? I found three pins "J1" marked P and N (Pal / Ntsc?), But I'm not sure if they are responsible for changing the region. Has anyone had / has such a clone and knows anything more ...
by sdm
Fri Jun 24, 2022 3:24 am
Forum: Homebrew Projects
Topic: My new game for NES. Project Commando :D
Replies: 7
Views: 974

Re: My new game for NES. Project Commando :D

Nice project, good luck :)
Fajny projekt, powodzenia ;)
by sdm
Sat Mar 26, 2022 2:15 am
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 39
Views: 2030

Re: snes assembly - beginnings, a few questions (wla-65816)

The issue you have is you think the assembler follows you code path, it doesn't. I know how assembler works and I know that it doesn't follow my thinking, it just translates line by line into machine code. My question concerns only the operation of the 8/16 modes of this processor, which is unclear...
by sdm
Fri Mar 25, 2022 3:37 pm
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 39
Views: 2030

Re: snes assembly - beginnings, a few questions (wla-65816)

Already a bit clearer. Will using together with SEP / REP additionally "hinting operand" eg LDA.W / LDA.B ... ..LDX.W etc, work similarly to using .ACCU 8 / .ACCU 16 / .INDEX 8 etc directives? So far I have no major problems in the code - just experimenting what and how it works. I try to ...
by sdm
Fri Mar 25, 2022 11:56 am
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 39
Views: 2030

Re: snes assembly - beginnings, a few questions (wla-65816)

Unfortunately, I apparently have problems understanding many things, or I have set it all wrong in my head: REP #$30 ; Sets A, X and Y to 16-bit mode PHB PHD PHA PHX PHY SEP #$20 ; Sets A to 8-bit mode JSR CopyOAMBuf (...) CopyOAMBuf: "---- assembler still knows that A is 16 bits and assembles ...
by sdm
Fri Mar 25, 2022 8:52 am
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 39
Views: 2030

Re: snes assembly - beginnings, a few questions (wla-65816)

Does changing the processor operating mode 8/16 bit before jumping to any function cause problems in the operation of the mode change? I noticed that changing before jumping to a function a at the beginning of that function causes a difference in how the mode change works. For example, the function ...
by sdm
Tue Mar 22, 2022 12:11 pm
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 39
Views: 2030

Re: snes assembly - beginnings, a few questions (wla-65816)

Will there be any difference when REP # $ 30 is set before PHB / PHD ? Is it better to do this before pushing the A / X / Y registers onto the stack? (does it matter at all) VBlank: REP #$30 ; A/mem=16 bits, X/Y=16 bits (to push all 16 bits) PHB PHD PHA PHX PHY (...) Or: VBlank: PHB PHD REP #$30 ; A...
by sdm
Tue Mar 22, 2022 10:03 am
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 39
Views: 2030

Re: snes assembly - beginnings, a few questions (wla-65816)

I cannot yet fully understand how register protection works after a VBLANK interrupt is performed. Is the processor working state 8/16 bit automatically secured at the time of interrupt execution and resumed automatically at the time of execution of "RTI"? For example, in the CPU-Loop I ha...
by sdm
Mon Mar 21, 2022 2:43 pm
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 39
Views: 2030

Re: snes assembly - beginnings, a few questions (wla-65816)

Thanks. One more problem I noticed is that the "default" screen is shifted one line up. Many Homebrews do exactly the same, and the screen is shifted up one line. Maybe a silly little thing, but I wonder why this is happening.. Writing to BG1 skroll vertical register fixed it, but I would ...
by sdm
Mon Mar 21, 2022 3:55 am
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 39
Views: 2030

Re: snes assembly - beginnings, a few questions (wla-65816)

What is the point of using e.g. LDA.W / STA.W in WLA-65816? At first I thought that using ".W / .B" (hinting operand) would make the assembler automatically set the correct 8/16 processor mode during compilation. But I still have to set SEP / REP before such an operation.
by sdm
Sun Mar 20, 2022 2:04 am
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 39
Views: 2030

Re: snes assembly - beginnings, a few questions (wla-65816)

That's right. Thanks. Now it is working. In 16-bit A mode, will Carry jump to AddrHI automatically in this case? : AddrLO DB ; wram AddrHI DB REP #$20 ; Sets A to 16-bit mode LDA AddrLO ; carry will jump into AddrHI increasing its value? (when the addition exceeds the 1-byte value) CLC ADC temp STA ...
by sdm
Sat Mar 19, 2022 3:55 pm
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 39
Views: 2030

Re: snes assembly - beginnings, a few questions (wla-65816)

What I mean: 4BPP PAL0 - COL00,COL01,COL02,COL03,COL04,COL05,COL06,COL07,COL08,COL09,COL10,COK11,COL12,COL13,COL14,COL15 4BPP PAL1 - COL00,COL01,COL02,COL03,COL04,COL05,COL06,COL07,COL08,COL09,COL10,COK11,COL12,COL13,COL14,COL15 4BPP PAL2 - COL00,COL01,COL02,COL03,COL04,COL05,COL06,COL07,COL08,COL09...