Added mixer and sound (c side)

src/main.c

@@ -20,12 +20,15 @@
 #include "image.h"
 #include "palette.h"
 #include "package.h"
+#include "soundblaster.h"
+#include "mixer.h"
 
 
 static lua_State *L;
 
 static void deinit(void) {
   /* Deinit and clear up everything. Called at exit */
+  soundblaster_deinit();
   vga_deinit();
   keyboard_deinit();
   lua_close(L);
@@ -59,6 +62,7 @@ int main(int argc, char **argv) {
   palette_init();
   keyboard_init();
   mouse_init();
+  soundblaster_init(mixer_getNextBlock);
 
   /* Init lua */
   L = luaL_newstate();

src/mixer.c

@@ -0,0 +1,90 @@
+#include <string.h>
+#include <dos.h>
+#include <stdbool.h>
+#include "mixer.h"
+#include "soundblaster.h"
+
+#define MIXER_MAX_SOUNDS 8
+
+typedef struct {
+  int offset;
+  sound_t const *sound;
+} mixed_sound_t;
+
+static mixed_sound_t sounds[MIXER_MAX_SOUNDS];
+static int activeSounds = 0;
+static int16_t data[SOUNDBLASTER_SAMPLES_PER_BUFFER] = {0};
+static bool canmix = true;
+
+void mixer_init(void) {
+}
+
+int16_t const * mixer_getNextBlock(void) {
+  canmix = true;
+  return data;
+}
+
+
+void mixer_play(sound_t const *sound) {
+  if(activeSounds == MIXER_MAX_SOUNDS) {
+    // TODO Replace older sound with new one instead?
+    return;
+  }
+
+  for(int i = 0; i < activeSounds; ++i) {
+    if(sounds[i].sound == sound) {
+      sounds[i].offset = 0;
+      return;
+    }
+  }
+
+  sounds[activeSounds].offset = 0;
+  sounds[activeSounds].sound = sound;
+  ++activeSounds;
+}
+
+static inline int16_t mix(int32_t a, int32_t b) {
+  int32_t res = a + b;
+  if(res > INT16_MAX)
+    res = INT16_MAX;
+  if(res < INT16_MIN)
+    res = INT16_MIN;
+  return res;
+}
+
+
+void mixer_mix(void) {
+  if(!canmix)
+    return;
+
+  memset(data, 0, SOUNDBLASTER_SAMPLES_PER_BUFFER);
+
+  for(int i = 0; i < activeSounds; ++i) {
+    mixed_sound_t *snd = sounds + i;
+    int len = snd->sound->sampleCount;
+    int16_t const* soundBuf = snd->sound->samples;
+
+    if(len > SOUNDBLASTER_SAMPLES_PER_BUFFER) {
+      len = SOUNDBLASTER_SAMPLES_PER_BUFFER;
+    }
+
+    for(int offset = 0; offset < len; ++offset) {
+      data[offset] = mix(data[offset], soundBuf[offset]);
+    }
+
+    snd->offset += len;
+
+
+  }
+
+
+  for(int i = activeSounds-1; i >= 0; --i) {
+    mixed_sound_t *snd = sounds + i;
+    if(snd->offset == snd->sound->sampleCount) {
+      *snd = sounds[activeSounds-1];
+      --activeSounds;
+    }
+  }
+
+  canmix = false;
+}

src/mixer.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <stdint.h>
+#include "sound.h"
+
+
+void mixer_init(void);
+void mixer_deinit(void);
+int16_t const* mixer_getNextBlock(void);
+void mixer_play(sound_t const *sound);
+void mixer_mix(void);

src/sound.c

@@ -0,0 +1,15 @@
+#include <stdint.h>
+#include "sound.h"
+#include "lib/dmt/dmt.h"
+
+int sound_init(sound_t *self, int samples) {
+  self->sampleCount = samples;
+  self->samples = (int16_t*)dmt_malloc(samples * sizeof(int16_t));
+  return 0;
+}
+
+
+void sound_deinit(sound_t *self) {
+  dmt_free(self->samples);
+}
+

src/sound.h

@@ -0,0 +1,14 @@
+#ifndef SOUND_H
+#define SOUND_H
+
+
+typedef struct  {
+  int sampleCount;
+  int16_t *samples;
+} sound_t;
+
+int sound_init(sound_t *self, int samples);
+void sound_deinit(sound_t *self);
+
+
+#endif

src/soundblaster.c

@@ -44,6 +44,8 @@ static uint16_t  dmaChannel;
 #define BLASTER_PROGRAM_STEREO               0x20
 #define BLASTER_PROGRAM_SIGNED               0x10
 #define BLASTER_SPEAKER_ON_CMD               0xD1
+#define BLASTER_SPEAKER_OFF_CMD              0xD3
+#define BLASTER_EXIT_AUTO_DMA                0xD9
 
 
 // PIC
@@ -78,8 +80,10 @@ static const struct  {
   { 0xC8, 0xCA, 0xD4, 0xD6, 0xD8, 0x89 },
   { 0xCC, 0xCE, 0xD4, 0xD6, 0xD8, 0x8A }
 };
+int stopDma = 0;
 
 // ISR data
+int isrInstalled = 0;
 static _go32_dpmi_seginfo oldBlasterHandler, newBlasterHandler;
 int writePage = 0;
 
@@ -87,14 +91,13 @@ static soundblaster_getSampleProc getSamples;
 
 static void writeDSP(uint8_t value) {
   while((inportb(baseAddress + BLASTER_WRITE_PORT) & 
-          BLASTER_WRITE_BUFFER_STATUS_UNAVAIL) != 0)
-    ;
+          BLASTER_WRITE_BUFFER_STATUS_UNAVAIL) != 0) {}
 
   outportb(baseAddress + BLASTER_WRITE_PORT, value);
 }
 
 
-static int resetBlaster() {
+static int resetBlaster(void) {
   for(int j = 0; j < 1000; ++j) {
     outportb(baseAddress + BLASTER_RESET_PORT, 1);
     delay(1);
@@ -112,19 +115,24 @@ static int resetBlaster() {
 }
 
 
-static void soundblasterISR() {
-  outportb(baseAddress + BLASTER_MIXER_OUT_PORT, 
-           BLASTER_MIXER_INTERRUPT_STATUS);
-  uint8_t status = inportb(baseAddress + BLASTER_MIXER_IN_PORT);
+static void soundblasterISR(void) {
+  if(stopDma == 1) {
+    writeDSP(BLASTER_EXIT_AUTO_DMA);
+    stopDma = 2;
+  } else {
+    outportb(baseAddress + BLASTER_MIXER_OUT_PORT, 
+             BLASTER_MIXER_INTERRUPT_STATUS);
+    uint8_t status = inportb(baseAddress + BLASTER_MIXER_IN_PORT);
 
-  if(status & BLASTER_16BIT_INTERRUPT) {
-    uint8_t* dst = (uint8_t*)(sampleBuffer)
-      + writePage * SAMPLE_BUFFER_SIZE / 2;
+    if(status & BLASTER_16BIT_INTERRUPT) {
+      uint8_t* dst = (uint8_t*)(sampleBuffer)
+        + writePage * SAMPLE_BUFFER_SIZE / 2;
 
-    memcpy(dst, getSamples(), SAMPLE_BUFFER_SIZE / 2);
+      memcpy(dst, getSamples(), SAMPLE_BUFFER_SIZE / 2);
 
-    writePage = 1 - writePage;
-    inportb(baseAddress + BLASTER_INTERRUPT_ACKNOWLEDGE_16BIT);
+      writePage = 1 - writePage;
+      inportb(baseAddress + BLASTER_INTERRUPT_ACKNOWLEDGE_16BIT);
+    }
   }
 
   if(irq >= 8) {
@@ -134,7 +142,7 @@ static void soundblasterISR() {
 }
 
 
-static void setBlasterISR() {
+static void setBlasterISR(void) {
   // Map IRQ to interrupt number on the CPU
   uint16_t interruptVector = irq + irq + (irq < 8)
     ? PIC_IRQ07_MAP
@@ -156,6 +164,8 @@ static void setBlasterISR() {
     uint8_t irqmask = inportb(PIC2_DATA);
     outportb(PIC2_DATA, irqmask & ~(1<<(irq-8)));
   }
+
+  isrInstalled = 1;
 }
 
 
@@ -175,7 +185,7 @@ static int parseBlasterSettings(void) {
 }
 
 
-static int allocSampleBuffer() {
+static int allocSampleBuffer(void) {
   static int maxRetries = 10;
   int selectors[maxRetries];
   int current;
@@ -211,11 +221,16 @@ static int allocSampleBuffer() {
 }
 
 
-static void turnSpeakerOn() {
+static void turnSpeakerOn(void) {
   writeDSP(BLASTER_SPEAKER_ON_CMD);
 }
 
 
+static void turnSpeakerOff(void) {
+  writeDSP(BLASTER_SPEAKER_OFF_CMD);
+}
+
+
 static void dmaSetupTransfer(int      channel,
                              uint8_t  direction,
                              bool     autoReload,
@@ -252,7 +267,7 @@ static void dmaSetupTransfer(int      channel,
 }
 
 
-static void startDMAOutput() {
+static void startDMAOutput(void) {
   uint32_t offset = (uint32_t)sampleBuffer;
 
   uint32_t samples = SAMPLE_BUFFER_SIZE / sizeof(int16_t);
@@ -302,6 +317,33 @@ int soundblaster_init(soundblaster_getSampleProc getsamplesproc) {
 }
 
 
-void soundblaster_deinit(void) {
-
+static void deallocSampleBuffer(void) {
+  __dpmi_free_dos_memory(sampleBufferSelector);
+}
+
+
+static void resetBlasterISR(void) {
+  if(isrInstalled == 1) {
+    uint16_t interruptVector = irq + irq + (irq < 8)
+      ? PIC_IRQ07_MAP
+      : PIC_IRQ8F_MAP;
+
+    _go32_dpmi_set_protected_mode_interrupt_vector(interruptVector, &oldBlasterHandler);
+    isrInstalled = 0;
+  }
+}
+
+
+static void stopDMAOutput(void) {
+  stopDma = 1;
+  while(stopDma == 1) {}
+}
+
+
+void soundblaster_deinit(void) {
+  turnSpeakerOff();
+  stopDMAOutput();
+  resetBlaster();
+  resetBlasterISR();
+  deallocSampleBuffer();
 }