shithub: wl3d

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disown opl2(1)

--- a/man/1/opl2

+++ /dev/null

@@ -1,62 +1,0 @@

-.TH OPL2 1

-.SH NAME

-opl2 \- OPL2 chip emulator

-.SH SYNOPSIS

-.B opl2

-[

-.B -n

-.I rate

-] [

-.I file

-]

-.SH DESCRIPTION

-.I Opl2

-is an emulator of a single Yamaha 3812 chip, also known as

-.SM OPL2.

-.PP

-The emulated chip is programmed by a stream of commands either from stdin or

-from

-.IR file .

-Guided by these commands, it then synthesizes a number of 16 bit little-endian samples for a sampling rate of 44.1 kHz.

-Each is duplicated for stereo sound and written to stdout.

-.PP

-While the output's sampling rate is the same as the audio device's default (see

-.IR audio (3)),

-the chip is meant to be sampled at a much lower rate, 700 Hz by default.

-A different expected sampling rate is given in Hz using the

-.B -n

-parameter.

-Internally, for each sample,

-.I opl2

-generates a number of additional samples depending on this rate.

-.PP

-Commands are 4 bytes formatted as follows, where the size of each field is given in bytes between brackets:

-.RS

-.IR register [1]

-.IR value [1]

-.IR delay [2]

-.RE

-.PP

-Each command specifies a

-.I value

-to be written to an

-.SM OPL2

-chip

-.IR register ,

-modifying its internal state.

-The

-.I delay

-field indicates a multiple of the expected sampling period (the inverse of the expected sampling rate) during which the chip should be sampled before processing the next command.

-Output is then triggered by a non-zero delay.

-.I Delay

-is stored as a 16-bit unsigned integer in little-endian byte order.

-.SH "SEE ALSO"

-.IR wl3d (1) ,

-.IR audio (3)

-.SH HISTORY

-.I Opl2

-first appeared for 9front (May, 2016), based on

-.I fmopl.c

-from the Multiple Arcade Machine Emulator (

-.SM MAME

-).

--- a/mkfile

+++ b/mkfile

@@ -1,11 +1,9 @@

 </$objtype/mkfile

-TARG=\

-	opl2\

-	wl3d\

+BIN=$home/bin/$objtype

+TARG=wl3d

-OFILES=

-WOFILES=\

+OFILES=\

 	drw.$O\

 	fs.$O\

 	gm.$O\

@@ -18,17 +16,10 @@

 HFILES= dat.h fns.h

-</sys/src/cmd/mkmany

-BIN=$home/bin/$objtype

+</sys/src/cmd/mkone

 sysinstall:V:

 	mkdir -p /sys/games/lib/wl3d

-	cp intro.wl6 intro.sod /sys/games/lib/wl3d

-	cp man/1/wl3d man/1/opl2 /sys/man/1

-	cp man/6/wl3d /sys/man/6

-

-$O.wl3d: $WOFILES

-	$LD -o $target $prereq

-

-$O.opl2: opl2.$O opl2m.$O

-	$LD -o $target $prereq

+	cp intro.wl6 intro.sod /sys/games/lib/wl3d/

+	cp man/1/wl3d /sys/man/1/

+	cp man/6/wl3d /sys/man/6/

--- a/opl2m.c

+++ /dev/null

@@ -1,65 +1,0 @@

-#include <u.h>

-#include <libc.h>

-#include <bio.h>

-

-uchar*	opl2out(uchar *, int);

-void	opl2wr(int, int);

-void	opl2init(int);

-

-enum{

-	Rate = 44100,

-	Hz = 700,

-	Samp = Rate / Hz

-};

-

-void

-usage(void)

-{

-	fprint(2, "usage: %s [-n nsamp] [file]\n", argv0);

-	exits("usage");

-}

-

-void

-main(int argc, char **argv)

-{

-	int n, r, v, dt, nsamp, fd;

-	uchar *sb, u[4];

-	Biobuf *bi, *bo;

-

-	fd = 0;

-	nsamp = Samp;

-	ARGBEGIN{

-	case 'n':

-		nsamp = Rate / atoi(EARGF(usage()));

-		break;

-	default:

-		usage();

-	}ARGEND;

-	if(*argv != nil){

-		fd = open(*argv, OREAD);

-		if(fd < 0)

-			sysfatal("open: %r");

-	}

-	bi = Bfdopen(fd, OREAD);

-	bo = Bfdopen(1, OWRITE);

-	if(bi == nil || bo == nil)

-		sysfatal("Bfdopen: %r");

-	nsamp *= 4;

-	sb = malloc(nsamp);

-	if(sb == nil)

-		sysfatal("malloc: %r");

-	opl2init(Rate);

-

-	while(n = Bread(bi, u, sizeof u), n > 0){

-		r = u[0];

-		v = u[1];

-		dt = u[3]<<8 | u[2];

-		opl2wr(r, v);

-		while(dt-- > 0){

-			opl2out(sb, nsamp);

-			Bwrite(bo, sb, nsamp);

-		}

-	}

-	if(n < 0)

-		sysfatal("Bread: %r");

-}