From b386c444c31133fd3cb64e0c02bbcc183501827e Mon Sep 17 00:00:00 2001
From: unknown <rmacri@users.noreply.github.com>
Date: Tue, 24 Mar 2015 12:04:32 +0900
Subject: [PATCH] Added GPL header, tweaked other comments

---
 source/DAC.cpp | 49 ++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 38 insertions(+), 11 deletions(-)

diff --git a/source/DAC.cpp b/source/DAC.cpp
index d0566dad..be88ceb7 100644
--- a/source/DAC.cpp
+++ b/source/DAC.cpp
@@ -1,10 +1,34 @@
 /*
-   Emulate an 8 bit DAC (eg: SAM card) which writes unsigned byte
-   data written to its IO area to the audio buffer (as used by the speaker).
-   This merges the data with the speaker stream, reducing the volume
-   of the Apple speaker when active.
+  AppleWin : An Apple //e emulator for Windows
 
-   Riccardo Macri  Mar 2015
+  Copyright (C) 1994-1996, Michael O'Brien
+  Copyright (C) 1999-2001, Oliver Schmidt
+  Copyright (C) 2002-2005, Tom Charlesworth
+  Copyright (C) 2006-2007, Tom Charlesworth, Michael Pohoreski
+
+  AppleWin is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  AppleWin is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with AppleWin; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+/*
+  DAC.CPP
+
+  Emulate an 8 bit DAC (eg: SAM card) which writes unsigned byte
+  data written to its IO area to the audio buffer (as used by the speaker).
+  This merges the data with the speaker stream, reducing the volume
+  of the Apple speaker when active.
+
+  Riccardo Macri  Mar 2015
 */
 #include "StdAfx.h"
 
@@ -28,7 +52,7 @@ static BYTE __stdcall IOWrite_DAC(WORD pc,  WORD addr, BYTE bWrite, BYTE d, ULON
 
  byte mb_res;
 
-  if (soundtype == SOUND_WAVE)
+ if (soundtype == SOUND_WAVE)
   {
    // use existing speaker code to bring timing up to date
    mb_res = SpkrToggle(pc, addr, bWrite, d, nCyclesLeft);
@@ -40,16 +64,19 @@ static BYTE __stdcall IOWrite_DAC(WORD pc,  WORD addr, BYTE bWrite, BYTE d, ULON
    //  0x00  0        0x80 -128
    
    // replace regular speaker output with 8 bit DAC value
-   // regular speaker data still audible but muted until speaker
-   // goes idle
+   // regular speaker data still audible but quieter until speaker
+   // goes idle (so both work simultaneously)
 
    g_nSpeakerData = (d ^ 0x80) << 8;
+
+   // make speaker quieter so eg: a metronome click through the
+   // Apple speaker is softer vs. the analogue SAM output
    g_quieterSpeaker = 1;
   }
-  else
-   mb_res = MemReadFloatingBus(nCyclesLeft);
+ else
+  mb_res = MemReadFloatingBus(nCyclesLeft);
 
-  return mb_res;
+ return mb_res;
 }
 
 void ConfigureDAC(LPBYTE pCxRomPeripheral, UINT uSlot)