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Sound Blaster DSP reset / status data ready bit

Posted on 2024-04-20, 14:11

What exactly is the correct behavior of the Sound Blaster DSP reset, specifically with the status data ready bit (bit 7). This guide: https://pdos.csail.mit.edu/6.828/2017/readings/hardware/SoundBlaster.pdf and the ESS datasheets agree that one should wait for the bit to be set before expecting to …

Re: ESS ES1688 PnP ROM dump

Posted on 2024-04-05, 12:41

Yeah, the ISA PnP protocol requires there to be a PnP ROM that lists all the logical devices, resources beloning to them and valid settings for all of them, etc., as well as the device's name. I've since been able to find an ES1688/968 PnP ROM listing here: https://cc.bingj.com/cache.aspx?q=% …

ESS ES1688 PnP ROM dump

Posted on 2024-04-04, 23:26

Does anyone here have a dump of the ESS ES1688 PnP ROM? Since the non-PnP ESS ES1688 is now emulated, I was curious if anyone has (or could dump) the ESS ES1688 PnP ROM so the emulation of the PnP version can be added as well. Thanks in advance!

Re: i430fx/i440fx APM?

Posted on 2024-03-17, 14:48

There is no power down sequence for the PIIX3, but Intel boards set up the PC87306 Super I/O chip to do a power down when the power supply is ATX, on ports 78h and 79h (the Super I/O chip's GPIO registers).

Re: 8042 output port bits 4/5?

Posted on 2024-02-15, 04:42

It always applies - if the input buffer is not full, then the keyboard controller has not received a byte, and if the output buffer is full, then there's a byte pending for the host to read. A command that wants one of more parameters is processed after every byte - if it wants more bytes, it …

Re: PCEM vs 86Box vs UniPCEM vs DosBox-X

Posted on 2023-11-06, 16:23

- solemgar: When comparing performance when emulating a 686 CPU, bear in mind that PCem's timings are less accurate and therefore, less calculation-intensive than ours. This may explain the discrepancy. - eddman: That could be the dynarec regression after v15. The new dynarec handles very poorly …

Re: PCEM vs 86Box vs UniPCEM vs DosBox-X

Posted on 2023-11-06, 04:45

- eddman: Actually, I wonder if the chain-4 changes to (S)VGA are the true reason for the current code of PCem being slower, in addition to the fact release builds are compiled with PGO (profile-guided optimization) likely tailored for common usage cases. One should actually compare PCem v17 vs. …

Re: PCEM vs 86Box vs UniPCEM vs DosBox-X

Posted on 2023-10-10, 00:27

If you mean PCem, yes, that's generally going to be faster than 86Box, for a few reasons: - We ship (and compile with) the old recompiler by default, because the new recompiler has some as of yet unfixed regressions (the Mapedit 8.x performance drop); - More accuracy in some parts, including but not …

Re: 8042 output port bits 4/5?

Posted on 2023-09-19, 14:49

And it looks like I typo'd above, I meant, until OBF is clear. Basically, there's two conditions for a command to be processed: IBF set and OBF clear, ie. there must be a byte in the input buffer and nothing in the output buffer.

Re: 8042 output port bits 4/5?

Posted on 2023-09-18, 18:55

- superfury: From what I see in the disassembled and commented IBM AT and PS/2 8042 firmwares on halicery (you need to use the Wayback Machine now since the site is now gone), commands are not processed until IBF is clear (ie. there is no incoming data to be read).

Re: Effect of ELCR set on the IRQ lines and 8259 PIC?

Posted on 2022-05-01, 16:16

I believe that's an erratum in the Intel PIIX/PIIX3 datasheet - I believe the specification update says it should be active high instead. So the effect is the same as setting the edge/level setting of the PIC (which does not work on the PIIX* precisely because the ELCR is meant to be used instead), …

Re: Ensoniq / Creative AudioPCI

Posted on 2022-01-20, 01:11

I have a question - how does the MIDI UART FIFO work on this? The datasheet is very unclear on this. There's 8 bytes of FIFO, but are all 8 bytes used for TX and RX together, are there 4 bytes for TX + 4 bytes for RX, or what's going on?

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