Add emulated Serial MIDI synthesizer support

.github/workflows/build.yml

@@ -40,7 +40,7 @@ jobs:
         with:
           msystem: MINGW64
           update: true
-          install: make git mingw-w64-x86_64-toolchain mingw-w64-x86_64-libelf mingw-w64-x86_64-SDL2
+          install: make git mingw-w64-x86_64-toolchain mingw-w64-x86_64-libelf mingw-w64-x86_64-SDL2 mingw-w64-x86_64-fluidsynth
       - uses: actions/setup-python@v5
         with:
           python-version: '3.9'
@@ -65,11 +65,31 @@ jobs:
         run: |
           git reset --hard
           git diff
-          TRACE=1 CROSS_COMPILE_WINDOWS=1 SDL2CONFIG=sdl2-config make V=1 -j2
+          TRACE=1 FLUIDSYNTH=1 CROSS_COMPILE_WINDOWS=1 SDL2CONFIG=sdl2-config make V=1 -j2
           mkdir emu_binaries
           cp $(which SDL2.dll) emu_binaries/.
           cp $(which zlib1.dll) emu_binaries/.
           cp $(which libwinpthread-1.dll) emu_binaries/.
+          cp $(which libfluidsynth-3.dll) emu_binaries/.
+          cp $(which libgcc_s_seh-1.dll) emu_binaries/.
+          cp $(which libglib-2.0-0.dll) emu_binaries/.
+          cp $(which libgmodule-2.0-0.dll) emu_binaries/.
+          cp $(which libportaudio.dll) emu_binaries/.
+          cp $(which libintl-8.dll) emu_binaries/.
+          cp $(which libstdc++-6.dll) emu_binaries/.
+          cp $(which libgomp-1.dll) emu_binaries/.
+          cp $(which libreadline8.dll) emu_binaries/.
+          cp $(which libsndfile-1.dll) emu_binaries/.
+          cp $(which libpcre2-8-0.dll) emu_binaries/.
+          cp $(which libiconv-2.dll) emu_binaries/.
+          cp $(which libtermcap-0.dll) emu_binaries/.
+          cp $(which libFLAC.dll) emu_binaries/.
+          cp $(which libmp3lame-0.dll) emu_binaries/.
+          cp $(which libmpg123-0.dll) emu_binaries/.
+          cp $(which libogg-0.dll) emu_binaries/.
+          cp $(which libopus-0.dll) emu_binaries/.
+          cp $(which libvorbis-0.dll) emu_binaries/.
+          cp $(which libvorbisenc-2.dll) emu_binaries/.
           cp sdcard.img.zip emu_binaries/.
           cp x16emu.exe emu_binaries/.
           cp makecart.exe emu_binaries/.
@@ -103,7 +123,7 @@ jobs:
         with:
           msystem: MINGW64
           update: true
-          install: make git mingw-w64-i686-toolchain mingw-w64-i686-libelf mingw-w64-i686-SDL2
+          install: make git mingw-w64-i686-toolchain mingw-w64-i686-libelf mingw-w64-i686-SDL2 mingw-w64-i686-fluidsynth
           path-type: inherit
       - uses: actions/setup-python@v5
         with:
@@ -131,11 +151,31 @@ jobs:
         run: |
           git reset --hard
           git diff
-          TRACE=1 WIN_SDL2=/mingw32 TARGET_CPU=x86 CROSS_COMPILE_WINDOWS=1 make V=1 -j2
+          TRACE=1 FLUIDSYNTH=1 WIN_SDL2=/mingw32 TARGET_CPU=x86 CROSS_COMPILE_WINDOWS=1 make V=1 -j2
           mkdir emu_binaries
           cp $(which SDL2.dll) emu_binaries/.
           cp $(which zlib1.dll) emu_binaries/.
           cp $(which libwinpthread-1.dll) emu_binaries/.
+          cp $(which libfluidsynth-3.dll) emu_binaries/.
+          cp $(which libgcc_s_seh-1.dll) emu_binaries/.
+          cp $(which libglib-2.0-0.dll) emu_binaries/.
+          cp $(which libgmodule-2.0-0.dll) emu_binaries/.
+          cp $(which libportaudio.dll) emu_binaries/.
+          cp $(which libintl-8.dll) emu_binaries/.
+          cp $(which libstdc++-6.dll) emu_binaries/.
+          cp $(which libgomp-1.dll) emu_binaries/.
+          cp $(which libreadline8.dll) emu_binaries/.
+          cp $(which libsndfile-1.dll) emu_binaries/.
+          cp $(which libpcre2-8-0.dll) emu_binaries/.
+          cp $(which libiconv-2.dll) emu_binaries/.
+          cp $(which libtermcap-0.dll) emu_binaries/.
+          cp $(which libFLAC.dll) emu_binaries/.
+          cp $(which libmp3lame-0.dll) emu_binaries/.
+          cp $(which libmpg123-0.dll) emu_binaries/.
+          cp $(which libogg-0.dll) emu_binaries/.
+          cp $(which libopus-0.dll) emu_binaries/.
+          cp $(which libvorbis-0.dll) emu_binaries/.
+          cp $(which libvorbisenc-2.dll) emu_binaries/.
           cp sdcard.img.zip emu_binaries/.
           cp x16emu.exe emu_binaries/.
           cp makecart.exe emu_binaries/.
@@ -165,7 +205,11 @@ jobs:
         with:
           python-version: '3.9'
       - name: Install Dependencies
-        run: sudo apt-get update && sudo apt-get install -y build-essential make libsdl2-dev
+        run: |
+          sudo cp /etc/apt/sources.list /etc/apt/sources.list~
+          sudo sed -Ei 's/^# deb-src /deb-src /' /etc/apt/sources.list
+          sudo apt-get update
+          sudo apt-get install -y build-essential make libsdl2-dev libfluidsynth-dev
       - name: Fetch latest ROM
         if: startsWith(github.ref, 'refs/tags/r') != true
         run: |
@@ -183,7 +227,7 @@ jobs:
           cp latest_rom/*.h src/.
       - name: Build Emulator
         run: |
-          TRACE=1 make V=1 -j3
+          TRACE=1 FLUIDSYNTH=1 make V=1 -j3
           mkdir emu_binaries
           cp sdcard.img.zip emu_binaries/.
           cp x16emu emu_binaries/.
@@ -241,8 +285,8 @@ jobs:
           copy_artifact_path: emu_binaries
           commands: |
             apt-get update
-            apt-get install -y build-essential make libsdl2-dev file git
-            TRACE=1 make V=1 -j3
+            apt-get install -y build-essential make libsdl2-dev file git libfluidsynth-dev
+            TRACE=1 FLUIDSYNTH=1 make V=1 -j3
             mkdir emu_binaries
             cp sdcard.img.zip emu_binaries/.
             cp x16emu emu_binaries/.
@@ -301,8 +345,8 @@ jobs:
           copy_artifact_path: emu_binaries
           commands: |
             apt-get update
-            apt-get install -y build-essential make libsdl2-dev file git
-            TRACE=1 make V=1 -j3
+            apt-get install -y build-essential make libsdl2-dev file git libfluidsynth-dev
+            TRACE=1 FLUIDSYNTH=1 make V=1 -j3
             mkdir emu_binaries
             cp sdcard.img.zip emu_binaries/.
             cp x16emu emu_binaries/.
@@ -333,7 +377,7 @@ jobs:
       - uses: actions/checkout@v4
       - name: Install Dependencies
         run: | 
-          brew install make sdl2 
+          brew install make sdl2 fluid-synth
       - uses: actions/setup-python@v5
         with:
           python-version: '3.9'
@@ -354,7 +398,7 @@ jobs:
           cp latest_rom/*.h src/.
       - name: Build Emulator
         run: |
-          TRACE=1 MAC_STATIC=1 LIBSDL_FILE=/usr/local/Cellar/sdl2/*/lib/libSDL2.a make V=1 -j3
+          TRACE=1 MAC_STATIC=1 LIBSDL_FILE=/usr/local/Cellar/sdl2/*/lib/libSDL2.a HOMEBREW_LIB=/usr/local/lib make V=1 -j3
           mkdir emu_binaries
           cp sdcard.img.zip emu_binaries/.
           cp x16emu emu_binaries/.
@@ -383,7 +427,7 @@ jobs:
       - uses: actions/checkout@v4
       - name: Install Dependencies
         run: | 
-          brew install make sdl2 
+          brew install make sdl2 fluid-synth
       - uses: actions/setup-python@v5
         with:
           python-version: '3.10'
@@ -404,7 +448,7 @@ jobs:
           cp latest_rom/*.h src/.
       - name: Build Emulator
         run: |
-          TRACE=1 MAC_STATIC=1 LIBSDL_FILE=/opt/homebrew/Cellar/sdl2/*/lib/libSDL2.a make V=1 -j3
+          TRACE=1 MAC_STATIC=1 LIBSDL_FILE=/opt/homebrew/Cellar/sdl2/*/lib/libSDL2.a ADDL_INCLUDE=/opt/homebrew/include HOMEBREW_LIB=/opt/homebrew/lib FLUIDSYNTH=1 make V=1 -j3
           mkdir emu_binaries
           cp sdcard.img.zip emu_binaries/.
           cp x16emu emu_binaries/.

Makefile

@@ -18,12 +18,10 @@ endif
 
 CFLAGS=-std=c99 -O3 -Wall -Werror -g $(shell $(SDL2CONFIG) --cflags) -Isrc/extern/include
 CXXFLAGS=-std=c++17 -O3 -Wall -Werror -Isrc/extern/ymfm/src
-LDFLAGS=$(shell $(SDL2CONFIG) --libs) -lm -lz
+LDFLAGS=$(shell $(SDL2CONFIG) --libs) -lm -lz -pthread
 
-# build with link time optimization
-ifndef NOLTO
-	CFLAGS+=-flto
-	LDFLAGS+=-flto
+ifdef ADDL_INCLUDE
+	CFLAGS+=-I$(ADDL_INCLUDE)
 endif
 
 X16_ODIR = build/x16emu
@@ -44,10 +42,9 @@ GIT_REV=$(shell git diff --quiet && /bin/echo -n $$(git rev-parse --short=8 HEAD
 CFLAGS+=-D GIT_REV='"$(GIT_REV)"'
 
 ifeq ($(MAC_STATIC),1)
-	LDFLAGS=$(LIBSDL_FILE) -lm -liconv -lz -Wl,-framework,CoreAudio -Wl,-framework,AudioToolbox -Wl,-framework,ForceFeedback -lobjc -Wl,-framework,CoreVideo -Wl,-framework,Cocoa -Wl,-framework,Carbon -Wl,-framework,IOKit -Wl,-weak_framework,QuartzCore -Wl,-weak_framework,Metal -Wl,-weak_framework,CoreHaptics -Wl,-weak_framework,GameController
-endif
-
-ifeq ($(CROSS_COMPILE_WINDOWS),1)
+	LDFLAGS=$(LIBSDL_FILE) -lm -liconv -lz -Wl,-framework,CoreAudio -Wl,-framework,AudioToolbox -Wl,-framework,ForceFeedback -lobjc -Wl,-framework,CoreVideo -Wl,-framework,Cocoa -Wl,-framework,Carbon -Wl,-framework,IOKit -Wl,-weak_framework,QuartzCore -Wl,-weak_framework,Metal -Wl,-weak_framework,CoreHaptics -Wl,-weak_framework,GameController -pthread
+	LDEMU=-ldl -Wl,-rpath,$(HOMEBREW_LIB)
+else ifeq ($(CROSS_COMPILE_WINDOWS),1)
 	LDFLAGS+=-L$(MINGW32)/lib
 	# this enables printf() to show, but also forces a console window
 	LDFLAGS+=-Wl,--subsystem,console
@@ -59,6 +56,14 @@ else
 	CC=x86_64-w64-mingw32-gcc
 	CXX=x86_64-w64-mingw32-g++
 endif
+else # Not Mac, not Windows, probably Linux
+	LDEMU=-ldl
+endif
+
+# build with link time optimization
+ifndef NOLTO
+	CFLAGS+=-flto
+	LDFLAGS+=-flto
 endif
 
 ifdef TARGET_WIN32
@@ -74,7 +79,11 @@ ifdef EMSCRIPTEN
 	MAKECART_OUTPUT=makecart.html
 endif
 
-_X16_OBJS = cpu/fake6502.o memory.o disasm.o video.o i2c.o smc.o rtc.o via.o serial.o ieee.o vera_spi.o audio.o vera_pcm.o vera_psg.o sdcard.o main.o debugger.o javascript_interface.o joystick.o rendertext.o keyboard.o icon.o timing.o wav_recorder.o testbench.o files.o cartridge.o iso_8859_15.o ymglue.o
+ifeq ($(FLUIDSYNTH),1)
+	CFLAGS+=-DHAS_FLUIDSYNTH
+endif
+
+_X16_OBJS = cpu/fake6502.o memory.o disasm.o video.o i2c.o smc.o rtc.o via.o serial.o ieee.o vera_spi.o audio.o vera_pcm.o vera_psg.o sdcard.o main.o debugger.o javascript_interface.o joystick.o rendertext.o keyboard.o icon.o timing.o wav_recorder.o testbench.o files.o cartridge.o iso_8859_15.o ymglue.o midi.o
 _X16_OBJS += extern/ymfm/src/ymfm_opm.o
 
 ifdef TARGET_WIN32
@@ -93,7 +102,7 @@ MAKECART_DEPS := $(MAKECART_OBJS:.o=.d)
 all: x16emu makecart
 
 x16emu: $(X16_OBJS)
-	$(CXX) -o $(X16_OUTPUT) $(X16_OBJS) $(LDFLAGS)
+	$(CXX) -o $(X16_OUTPUT) $(X16_OBJS) $(LDFLAGS) $(LDEMU)
 
 $(X16_ODIR)/%.o: $(X16_SDIR)/%.c
 	@mkdir -p $$(dirname $@)

src/audio.c

@@ -8,6 +8,7 @@
 #include "vera_pcm.h"
 #include "wav_recorder.h"
 #include "ymglue.h"
+#include "midi.h"
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
@@ -23,6 +24,7 @@
 
 #define VERA_SAMP_CLKS_PER_CPU_CLK ((25000000ULL << SAMP_POS_FRAC_BITS) / 512 / MHZ / 1000000)
 #define YM_SAMP_CLKS_PER_CPU_CLK ((3579545ULL << SAMP_POS_FRAC_BITS) / 64 / MHZ / 1000000)
+#define FS_SAMP_CLKS_PER_CPU_CLK VERA_SAMP_CLKS_PER_CPU_CLK
 #define SAMPLE_BYTES (2 * sizeof(int16_t))
 #define SAMP_POS_MASK (SAMPLES_PER_BUFFER - 1)
 #define SAMP_POS_MASK_FRAC (((uint32_t)SAMPLES_PER_BUFFER << SAMP_POS_FRAC_BITS) - 1)
@@ -75,13 +77,18 @@ static uint32_t vera_samp_pos_hd = 0;
 static uint32_t ym_samp_pos_rd = 0;
 static uint32_t ym_samp_pos_wr = 0;
 static uint32_t ym_samp_pos_hd = 0;
+static uint32_t fs_samp_pos_rd = 0;
+static uint32_t fs_samp_pos_wr = 0;
+static uint32_t fs_samp_pos_hd = 0;
 static uint32_t vera_samps_per_host_samps = 0;
 static uint32_t ym_samps_per_host_samps = 0;
+static uint32_t fs_samps_per_host_samps = 0;
 static uint32_t limiter_amp = 0;
 
 static int16_t psg_buf[2 * SAMPLES_PER_BUFFER];
 static int16_t pcm_buf[2 * SAMPLES_PER_BUFFER];
 static int16_t ym_buf[2 * SAMPLES_PER_BUFFER];
+static int16_t fs_buf[2 * SAMPLES_PER_BUFFER];
 
 uint32_t host_sample_rate = 0;
 
@@ -181,17 +188,22 @@ audio_init(const char *dev_name, int num_audio_buffers)
 	host_sample_rate = obtained.freq;
 	vera_samps_per_host_samps = ((25000000ULL << SAMP_POS_FRAC_BITS) / 512 / host_sample_rate);
 	ym_samps_per_host_samps = ((3579545ULL << SAMP_POS_FRAC_BITS) / 64 / host_sample_rate);
+	fs_samps_per_host_samps = vera_samps_per_host_samps;
 	vera_samp_pos_rd = 0;
 	vera_samp_pos_wr = 0;
 	vera_samp_pos_hd = 0;
 	ym_samp_pos_rd = 0;
 	ym_samp_pos_wr = 0;
 	ym_samp_pos_hd = 0;
+	fs_samp_pos_rd = 0;
+	fs_samp_pos_wr = 0;
+	fs_samp_pos_hd = 0;
 	limiter_amp = (1 << 16);
 
 	psg_buf[0] = psg_buf[1] = 0;
 	pcm_buf[0] = pcm_buf[1] = 0;
 	ym_buf[0] = ym_buf[1] = 0;
+	fs_buf[0] = fs_buf[1] = 0;
 
 	// Start playback
 	SDL_PauseAudioDevice(audio_dev, 0);
@@ -228,6 +240,7 @@ audio_step(int cpu_clocks)
 		uint32_t max_cpu_clks = SDL_min(cpu_clocks, max_cpu_clks_ym);
 		vera_samp_pos_hd = (vera_samp_pos_hd + max_cpu_clks * VERA_SAMP_CLKS_PER_CPU_CLK) & SAMP_POS_MASK_FRAC;
 		ym_samp_pos_hd = (ym_samp_pos_hd + max_cpu_clks * YM_SAMP_CLKS_PER_CPU_CLK) & SAMP_POS_MASK_FRAC;
+		fs_samp_pos_hd = (fs_samp_pos_hd + max_cpu_clks * FS_SAMP_CLKS_PER_CPU_CLK) & SAMP_POS_MASK_FRAC;
 		cpu_clocks -= max_cpu_clks;
 		if (cpu_clocks > 0) audio_render();
 	}
@@ -271,16 +284,31 @@ audio_render()
 		YM_stream_update((uint16_t *)&ym_buf[pos * 2], len);
 	}
 
+	pos = (fs_samp_pos_wr + 1) & SAMP_POS_MASK;
+	len = ((fs_samp_pos_hd >> SAMP_POS_FRAC_BITS) - fs_samp_pos_wr) & SAMP_POS_MASK;
+	fs_samp_pos_wr = fs_samp_pos_hd >> SAMP_POS_FRAC_BITS;
+	if ((pos + len) > SAMPLES_PER_BUFFER) {
+		midi_synth_render(&fs_buf[pos * 2], SAMPLES_PER_BUFFER - pos);
+		len -= SAMPLES_PER_BUFFER - pos;
+		pos = 0;
+	}
+	if (len > 0) {
+		midi_synth_render(&fs_buf[pos * 2], len);
+	}
+
 	uint32_t wridx_old = wridx;
 	uint32_t len_vera = (vera_samp_pos_hd - vera_samp_pos_rd) & SAMP_POS_MASK_FRAC;
 	uint32_t len_ym = (ym_samp_pos_hd - ym_samp_pos_rd) & SAMP_POS_MASK_FRAC;
-	if (len_vera < (4 << SAMP_POS_FRAC_BITS) || len_ym < (4 << SAMP_POS_FRAC_BITS)) {
+	uint32_t len_fs = (fs_samp_pos_hd - fs_samp_pos_rd) & SAMP_POS_MASK_FRAC;
+	if (len_vera < (4 << SAMP_POS_FRAC_BITS) || len_ym < (4 << SAMP_POS_FRAC_BITS) || len_fs < (4 << SAMP_POS_FRAC_BITS)) {
 		// not enough samples yet, at least 4 are needed for the filter
 		return;
 	}
 	len_vera = (len_vera - (4 << SAMP_POS_FRAC_BITS)) / vera_samps_per_host_samps;
 	len_ym = (len_ym - (4 << SAMP_POS_FRAC_BITS)) / ym_samps_per_host_samps;
+	len_fs = (len_fs - (4 << SAMP_POS_FRAC_BITS)) / fs_samps_per_host_samps;
 	len = SDL_min(len_vera, len_ym);
+	len = SDL_min(len, len_fs);
 	SDL_LockAudioDevice(audio_dev);
 	for (int i = 0; i < len; i++) {
 		int32_t samp[8];
@@ -289,6 +317,8 @@ audio_render()
 		int32_t vera_out_r = 0;
 		int32_t ym_out_l = 0;
 		int32_t ym_out_r = 0;
+		int32_t fs_out_l = 0;
+		int32_t fs_out_r = 0;
 		// Don't resample VERA outputs if the host sample rate is as desired
 		if (host_sample_rate == AUDIO_SAMPLERATE) {
 			pos = (vera_samp_pos_rd >> SAMP_POS_FRAC_BITS) * 2;
@@ -326,11 +356,33 @@ audio_render()
 		ym_out_r += samp[5] * filter[255 - filter_idx];
 		ym_out_l += samp[6] * filter[511 - filter_idx];
 		ym_out_r += samp[7] * filter[511 - filter_idx];
-		// Mixing is according to the Developer Board
+		// Don't resample MIDI synth outputs if the host sample rate matches it
+		if (host_sample_rate == AUDIO_SAMPLERATE) {
+			pos = (fs_samp_pos_rd >> SAMP_POS_FRAC_BITS) * 2;
+			fs_out_l = (uint32_t)fs_buf[pos] << 14;
+			fs_out_r = (uint32_t)fs_buf[pos + 1] << 14;
+		} else {
+			filter_idx = (fs_samp_pos_rd >> (SAMP_POS_FRAC_BITS - 8)) & 0xff;
+			pos = (fs_samp_pos_rd >> SAMP_POS_FRAC_BITS) * 2;
+			for (int j = 0; j < 8; j += 2) {
+				samp[j] = fs_buf[pos];
+				samp[j + 1] = fs_buf[pos + 1];
+				pos = (pos + 2) & (SAMP_POS_MASK * 2);
+			}
+			fs_out_l += samp[0] * filter[256 + filter_idx];
+			fs_out_r += samp[1] * filter[256 + filter_idx];
+			fs_out_l += samp[2] * filter[  0 + filter_idx];
+			fs_out_r += samp[3] * filter[  0 + filter_idx];
+			fs_out_l += samp[4] * filter[255 - filter_idx];
+			fs_out_r += samp[5] * filter[255 - filter_idx];
+			fs_out_l += samp[6] * filter[511 - filter_idx];
+			fs_out_r += samp[7] * filter[511 - filter_idx];
+		}
+		// VERA+YM mixing is according to the Developer Board
 		// Loudest single PSG channel is 1/8 times the max output
-		// mix = (psg + pcm) * 2 + ym
-		int32_t mix_l = (vera_out_l >> 13) + (ym_out_l >> 15);
-		int32_t mix_r = (vera_out_r >> 13) + (ym_out_r >> 15);
+		// mix = (psg + pcm) * 2 + ym + fs * 4
+		int32_t mix_l = (vera_out_l >> 13) + (ym_out_l >> 15) + (fs_out_l >> 12);
+		int32_t mix_r = (vera_out_r >> 13) + (ym_out_r >> 15) + (fs_out_r >> 12);
 		uint32_t amp = SDL_max(SDL_abs(mix_l), SDL_abs(mix_r));
 		if (amp > 32767) {
 			uint32_t limiter_amp_new = (32767 << 16) / amp;
@@ -341,6 +393,7 @@ audio_render()
 		if (limiter_amp < (1 << 16)) limiter_amp++;
 		vera_samp_pos_rd = (vera_samp_pos_rd + vera_samps_per_host_samps) & SAMP_POS_MASK_FRAC;
 		ym_samp_pos_rd = (ym_samp_pos_rd + ym_samps_per_host_samps) & SAMP_POS_MASK_FRAC;
+		fs_samp_pos_rd = (fs_samp_pos_rd + fs_samps_per_host_samps) & SAMP_POS_MASK_FRAC;
 		if (wridx == buffer_size) {
 			wav_recorder_process(&buffer[wridx_old], (buffer_size - wridx_old) / 2);
 			wridx = 0;
@@ -368,6 +421,10 @@ audio_render()
 	if (skip > 1) {
 		ym_samp_pos_rd = (ym_samp_pos_rd + ym_samps_per_host_samps) & SAMP_POS_MASK_FRAC;
 	}
+	skip = len_fs - len;
+	if (skip > 1) {
+		fs_samp_pos_rd = (fs_samp_pos_rd + fs_samps_per_host_samps) & SAMP_POS_MASK_FRAC;
+	}
 }
 
 void