mirror of
https://github.com/AppleWin/AppleWin.git
synced 2024-11-05 06:06:24 +00:00
bbe88da787
. Split AppleWin -> Core with the functionality really needed by the emulator. . Split AppleWin -> Utilities for generic code not called by other emulator components. . Split AppleWin -> CmdLine for the command line option parsing.
93 lines
3.2 KiB
C++
93 lines
3.2 KiB
C++
/*
|
|
AppleWin : An Apple //e emulator for Windows
|
|
|
|
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
|
|
*/
|
|
/*
|
|
SAM.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"
|
|
|
|
#include "SAM.h"
|
|
#include "Memory.h"
|
|
#include "Speaker.h"
|
|
|
|
//
|
|
// Write 8 bit data to speaker. Emulates a "SAM" speech card DAC
|
|
//
|
|
|
|
|
|
static BYTE __stdcall IOWrite_SAM(WORD pc, WORD addr, BYTE bWrite, BYTE d, ULONG nExecutedCycles)
|
|
{
|
|
// Emulate audio from a SAM / 8 bit DAC card
|
|
// Only supportable if AppleWin is using WAVE output
|
|
//
|
|
// This works by using the existing speaker handling but then
|
|
// replacing the speaker audio with the 8 bit samples from the DAC
|
|
// before they get sent out to the soundcard buffer, whilst
|
|
// audio samples are being written to the SAM.
|
|
//
|
|
// Whilst very unusual, it is possible to intermingle use of SAM and the apple
|
|
// speaker. This is crudely supported with g_bQuieterSpeaker making the Apple
|
|
// speaker produce quieter clicks which will be crudely intermingled
|
|
// with the SAM data. The mute gets reset after the speaker code detects
|
|
// silence.
|
|
|
|
if (soundtype != SOUND_WAVE)
|
|
return MemReadFloatingBus(nExecutedCycles);
|
|
|
|
// use existing speaker code to bring timing up to date
|
|
BYTE res = SpkrToggle(pc, addr, bWrite, d, nExecutedCycles);
|
|
|
|
// The DAC in the SAM uses unsigned 8 bit samples
|
|
// The WAV data that g_nSpeakerData is loaded into is a signed short
|
|
//
|
|
// We convert unsigned 8 bit to signed by toggling the most significant bit
|
|
//
|
|
// SAM card WAV driver SAM WAV
|
|
// 0xFF 255 0x7f 127 _ FF 7F
|
|
// 0x81 129 0x01 1 / \ .
|
|
// 0x80 128 0x00 0 / \ /80 00
|
|
// 0x7f 127 0xFF -1 \_/
|
|
// 0x00 0 0x80 -128 00 80
|
|
//
|
|
// SAM is 8 bit, PC WAV is 16 so shift audio to the MSB (<< 8)
|
|
|
|
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_bQuieterSpeaker = true;
|
|
|
|
return res;
|
|
}
|
|
|
|
void ConfigureSAM(LPBYTE pCxRomPeripheral, UINT uSlot)
|
|
{
|
|
RegisterIoHandler(uSlot, IO_Null, IOWrite_SAM, IO_Null, IO_Null, NULL, NULL);
|
|
}
|