Import of initial version of SoundControl (HAL variant).

This module pinches the name, SWI base and error block of its Phoebe
equivalent (now moved to RiscOS/Sources/Audio/SoundCtrlPhoebe), but is a
completely new implementation.

hdr/MixerDevice

+; Copyright 2003 Tematic Ltd
+;
+; Licensed under the Apache License, Version 2.0 (the "License");
+; you may not use this file except in compliance with the License.
+; You may obtain a copy of the License at
+;
+;     http://www.apache.org/licenses/LICENSE-2.0
+;
+; Unless required by applicable law or agreed to in writing, software
+; distributed under the License is distributed on an "AS IS" BASIS,
+; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+; See the License for the specific language governing permissions and
+; limitations under the License.
+;
+
+; Public interface (ie interface to SoundControl) of DMA audio mixer devices
+
+        GET     hdr:HALDevice
+
+OldOpt  SETA    {OPT}
+        OPT     OptNoList+OptNoP1List
+
+ [ :LNOT: :DEF: Included_Hdr_MixerDevice
+                         GBLL Included_Hdr_MixerDevice
+Included_Hdr_MixerDevice SETL {TRUE}
+
+; Device for each DMA controller
+
+                                ^       0
+                                #       HALDeviceSize
+HALDevice_MixerCtrlr            #       4
+HALDevice_MixerChannels         #       4
+HALDevice_MixerGetFeatures      #       4
+HALDevice_MixerSetMix           #       4
+HALDevice_MixerGetMix           #       4
+HALDevice_Mixer_Size            *       :INDEX: @
+
+MixerFeaturesFlag_Fixed         *       1 :SHL: 0
+MixerFeaturesFlag_Mono          *       1 :SHL: 1
+MixerFeaturesFlag_DefaultMute   *       1 :SHL: 2
+MixerFeaturesShift_Category     *       16
+MixerFeaturesMask_Category      *       &FFFF :SHL: MixerFeaturesShift_Category
+
+MixerMixFlag_Mute               *       1 :SHL: 0
+
+MixerCategory_Speaker           *       -1
+MixerCategory_Headphones        *       -2
+MixerCategory_LineOut           *       -3
+MixerCategory_AuxOut            *       -4
+MixerCategory_System            *       0
+MixerCategory_Mic               *       1
+MixerCategory_LineIn            *       2
+MixerCategory_AuxIn             *       3
+
+ ]
+
+        OPT     OldOpt
+        END

hdr/SoundCtrl

+; Copyright 2003 Tematic Ltd
+;
+; Licensed under the Apache License, Version 2.0 (the "License");
+; you may not use this file except in compliance with the License.
+; You may obtain a copy of the License at
+;
+;     http://www.apache.org/licenses/LICENSE-2.0
+;
+; Unless required by applicable law or agreed to in writing, software
+; distributed under the License is distributed on an "AS IS" BASIS,
+; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+; See the License for the specific language governing permissions and
+; limitations under the License.
+;
+        SUBT    Exported Sound Control constants
+
+OldOpt  SETA    {OPT}
+        OPT     OptNoList+OptNoP1List
+
+; ***********************************
+; ***    C h a n g e   L i s t    ***
+; ***********************************
+
+; Date       Name  Description
+; ----       ----  -----------
+; 14-Feb-03  BJGA  Created.
+;
+SWIClass        SETS    SoundCtrlSWI_Name
+
+        ^       SoundCtrlSWI_Base
+
+        AddSWI  ExamineMixer
+        AddSWI  SetMix
+        AddSWI  GetMix
+
+                                ^       ErrorBase_SoundCtrl
+Error_SoundCtrl_BadSWI          #       1
+Error_SoundCtrl_NoMem           #       1
+Error_SoundCtrl_BadMixer        #       1
+Error_SoundCtrl_BadChannel      #       1
+
+        OPT     OldOpt
+
+        END