games/dmid uses the same sample rate as the chip for music, but other
applications do not. opl3 and its older version opl2 (not in 9front)
read an input stream of commands in basically IMF format, something
used in other id Software games and some others, which assumes a
given input sampling rate: 700 Hz for Wolfenstein 3D music, 560 Hz
for Commander Keen, 60 Hz for Ultima 6, etc.
The opl3 emulation on the other hand is not really intended to run at
a sampling rate different that the chip's 49.716 kHz sampling rate.
Previously, we assumed it runs at 44.1 kHz and just used the input
rate as a divisor to get the number of samples per delay tic.
From what I understand, the correct way to use it for accurate
emulation is to run the opl chip emulator at its intended sampling
frequency, then downsample to 44.1 kHz. This means better output
but more code. The alternative is to basically do the same as
before rev 8433, except with no buffering, but at accuracy/quality
loss. This change implements the former and just forks pcmconv to
deal with resampling.
this fixes real-time applications.
-n previously specified a rate divisor rather than the rate itself,
which was used for specific applications outside of 9front. instead,
just set the rate directly, more useful and straightforward.
i have found one bug. when i put glenda in a position like this
i somehow win, but the glenda can escape from there.
in addition, i have changed the games manpage to include more info about glendy.
I'm not sure if this LFSR is the same one used by the hardware or is
arbitrary, but it matches the noise sequence used by all other snes
emulators I looked at.
s1 and s2 should store the last and next to last output, but were set
in the wrong order, causing them both to be the last output. This
breaks filters 2 and 3, which both utilize s2.
H-blank DMA should only transfer 16 bytes per h-blank, rather than
waiting for the first h-blank and then transferring the whole size.
HDMAC should read 0xff when the transfer is finished, and 0 in the
high bit when the transfer is ongoing. Also, if 0 is written in the
high bit, the current transfer should be aborted.
Introduce two flags, DMAREADY and DMAHBLANK rather than special
constants 1 and -1. If dma is non-zero, there is an ongoing DMA. If
DMAREADY is set, the next chunk is ready to transfer.
Reference: https://gbdev.io/pandocs/#ff55-hdma5-cgb-mode-only-new-dma-length-mode-start
Tested with pokemon crystal.
What was happening is that when the game was loading N background tiles
into vram (each 16 bytes, so one per h-blank), it did something like
this:
- start an hdma transfer for N+1 tiles
- after the Nth tile is transferred, it would read HDMA5, clear the
high bit, then write it back to abort the transfer.
games/gb would instead transfer all N+1 tiles at once, overwriting one
extra tile with whatever was 1 past the end of the source array, and
then would interpret the cancel request as the start of a new transfer
of 16 bytes, which would copy an additional tile past the end. The end
result is that every transfer would end up copying N+2 tiles instead
of just N, overwriting certain tiles with whatever was after the end
of the source data.
According to [0], input clock 0 should divide by 1024=2¹⁰, not 2¹².
This caused audio to run at quarter-speed in one game I tried.
[0] https://gbdev.io/pandocs/#ff07-tac-timer-control-r-w
Tested with zelda: oracle of seasons, and dr. mario
---
Plan 9 memcpy(2) uses the same implementation as memmove(2) to handle
overlapping ranges. Hovewer, the MIX MOVE instruction, as described
in TAOCP, specifically does not do this. It copies words one at a
time starting from the lowest address.
This change also expands the address validation to check that all
addresses within the source and destination ranges are valid before
proceeding.
The mount() and bind() syscalls return -1 on error,
and the mountid sequence number on success.
The manpage states that the mountid sequence number
is a positive integer, but the kernels implementation
currently uses a unsigned 32-bit integer and does not
guarantee that the mountid will not become negative.
Most code just cares about the error, so test for
the -1 error value only.
revert last change, which used games/wadfs to expose genmidi and music lumps.
replacements from patch wads were never seen that way. instead, write genmidi
and music lumps to /tmp and play them from there.
launch wadfs after detecting main wad, exposing GENMIDI and music lumps
under /mnt/wad. /bin/dmus can then use them directly, and wadfs doesn't
need to be started manually.
- fix overwriting channel 10 with channel 9
- fix using channel volume instead of last volume when setting note
(fixes d_doom and others)
- remove useless state
rodri
qwx
Sigrid
cinap_lenrek
Michael Forney
Alex Musolino
Ori Bernstein