From 96edd67bb7e93df34e61ed835827819e7445f2da Mon Sep 17 00:00:00 2001
From: Sjoerd van der Berg <harekiet@users.sourceforge.net>
Date: Sat, 30 Nov 2002 11:54:54 +0000
Subject: [PATCH] Sinewave and disabling support, although sine is buggy.

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@551
---
 src/hardware/pcspeaker.cpp | 78 ++++++++++++++++++++++++++++----------
 1 file changed, 59 insertions(+), 19 deletions(-)

diff --git a/src/hardware/pcspeaker.cpp b/src/hardware/pcspeaker.cpp
index 5043df46..f85f2891 100644
--- a/src/hardware/pcspeaker.cpp
+++ b/src/hardware/pcspeaker.cpp
@@ -20,6 +20,7 @@
 #include "dosbox.h"
 #include "mixer.h"
 #include "timer.h"
+#include "setup.h"
 
 
 #ifndef PI
@@ -30,20 +31,25 @@
 #define SPKR_RATE 22050
 #define SPKR_VOLUME 5000
 
-#define FREQ_SHIFT 16
-#define FREQ_MAX (2 << FREQ_SHIFT)
+#define SPKR_SHIFT 16
+
+#define SIN_ENT 1024
+#define SIN_MAX (SIN_ENT << SPKR_SHIFT)
+
+#define FREQ_MAX (2 << SPKR_SHIFT)
 #define FREQ_HALF (FREQ_MAX >> 1)
 
-
-
 struct Speaker {
-	Bit32u freq_add;
-	Bit32u freq_pos;
+	Bitu freq_add;
+	Bitu freq_pos;
 	Bit16s volume;
 	MIXER_Channel * chan;
 	bool enabled;
 	bool realsound;
+	bool sinewave;
+	Bitu mode;
 	Bit16u buffer[SPKR_BUF];
+	Bit16s table[SIN_ENT];
 	Bitu buf_pos;
 };
 
@@ -52,6 +58,7 @@ static Speaker spkr;
 
 
 void PCSPEAKER_SetCounter(Bitu cntr,Bitu mode) {
+	spkr.mode=mode;
 	switch (mode) {
 	case 0:
 		if (cntr>72) cntr=72;
@@ -59,8 +66,14 @@ void PCSPEAKER_SetCounter(Bitu cntr,Bitu mode) {
 		if (spkr.buf_pos<SPKR_BUF) spkr.buffer[spkr.buf_pos++]=(cntr-36)*600;
 		break;
 	case 3:
-		spkr.freq_add=(Bit32u)(FREQ_MAX/((float)SPKR_RATE/(PIT_TICK_RATE/(float)cntr)));
+		if (spkr.sinewave) {
+			spkr.freq_add=(Bitu)(SIN_MAX/((float)SPKR_RATE/(PIT_TICK_RATE/(float)cntr)));
+		} else {
+			spkr.freq_add=(Bitu)(FREQ_MAX/((float)SPKR_RATE/(PIT_TICK_RATE/(float)cntr)));
+		}
 		break;
+	case 4:
+		spkr.freq_pos=(Bitu)(SPKR_RATE/(PIT_TICK_RATE/(float)cntr));
 	}
 }
 
@@ -70,19 +83,27 @@ void PCSPEAKER_Enable(bool enable) {
 }
 
 static void PCSPEAKER_CallBack(Bit8u * stream,Bit32u len) {
-	if (spkr.realsound) {
-	/* Generate the "RealSound" */
-		Bitu buf_add=(spkr.buf_pos<<16)/len;
-		Bitu buf_pos=0;
-		spkr.buf_pos=0;spkr.realsound=0;
-		while (len-->0) {
-			*(Bit16s*)(stream)=spkr.buffer[buf_pos >> 16];
-			buf_pos+=buf_add;
-			stream+=2;
+	switch (spkr.mode) {
+	case 0:
+		/* Generate the "RealSound" */
+		{
+			Bitu buf_add=(spkr.buf_pos<<16)/len;
+			Bitu buf_pos=0;
+			spkr.buf_pos=0;spkr.realsound=0;
+			while (len-->0) {
+				*(Bit16s*)(stream)=spkr.buffer[buf_pos >> 16];
+				buf_pos+=buf_add;
+				stream+=2;
+			}
+			break;
 		}
-	} else {
-	/* Generate a square wave */
-		while (len-->0) {
+	case 3:
+		if (spkr.sinewave) while (len-->0) {
+			spkr.freq_pos+=spkr.freq_add;
+			spkr.freq_pos&=(SIN_MAX-1);
+			*(Bit16s*)(stream)=spkr.table[spkr.freq_pos>>SPKR_SHIFT];
+			stream+=2;
+		} else while (len-->0) {
 			spkr.freq_pos+=spkr.freq_add;
 			if (spkr.freq_pos>=FREQ_MAX) spkr.freq_pos-=FREQ_MAX;
 			if (spkr.freq_pos>=FREQ_HALF) {
@@ -92,11 +113,26 @@ static void PCSPEAKER_CallBack(Bit8u * stream,Bit32u len) {
 			}
 			stream+=2;
 		}
+		break;
+	case 4:
+		while (len-->0) {
+			if (spkr.freq_pos) {
+				*(Bit16s*)(stream)=spkr.volume;
+				spkr.freq_pos--;
+			} else {
+				*(Bit16s*)(stream)=-spkr.volume;
+			}
+			stream+=2;
+		}
+		break;
 	}
 }
 
 void PCSPEAKER_Init(Section* sec) {
     MSG_Add("SPEAKER_CONFIGFILE_HELP","pcspeaker related options.\n");
+	Section_prop * section=static_cast<Section_prop *>(sec);
+	if(!section->Get_bool("enabled")) return;
+	spkr.sinewave=section->Get_bool("sinewave");
 	spkr.chan=MIXER_AddChannel(&PCSPEAKER_CallBack,SPKR_RATE,"PC-SPEAKER");
 	MIXER_Enable(spkr.chan,false);
 	MIXER_SetMode(spkr.chan,MIXER_16MONO);
@@ -104,4 +140,8 @@ void PCSPEAKER_Init(Section* sec) {
 	spkr.enabled=false;
 	spkr.realsound=false;
 	spkr.buf_pos=0;
+	/* Generate the sine wave */
+	for (Bitu i=0;i<SIN_ENT;i++) {
+		spkr.table[i]=(Bit16s)(sin(2*PI/SIN_ENT*i)*SPKR_VOLUME*1.5);
+	}
 }