2 files changed, 327 insertions, 0 deletions

diff --git a/contrib/SDL-3.2.8/src/audio/n3ds/SDL_n3dsaudio.c b/contrib/SDL-3.2.8/src/audio/n3ds/SDL_n3dsaudio.c
new file mode 100644
index 0000000..780b06c
--- /dev/null
+++ b/contrib/SDL-3.2.8/src/audio/n3ds/SDL_n3dsaudio.c
@@ -0,0 +1,287 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_internal.h"
+
+#ifdef SDL_AUDIO_DRIVER_N3DS
+
+// N3DS Audio driver
+
+#include "../SDL_sysaudio.h"
+#include "SDL_n3dsaudio.h"
+
+#define N3DSAUDIO_DRIVER_NAME "n3ds"
+
+static dspHookCookie dsp_hook;
+static SDL_AudioDevice *audio_device;
+
+// fully local functions related to the wavebufs / DSP, not the same as the `device->lock` SDL_Mutex!
+static SDL_INLINE void contextLock(SDL_AudioDevice *device)
+{
+    LightLock_Lock(&device->hidden->lock);
+}
+
+static SDL_INLINE void contextUnlock(SDL_AudioDevice *device)
+{
+    LightLock_Unlock(&device->hidden->lock);
+}
+
+static void N3DSAUD_DspHook(DSP_HookType hook)
+{
+    if (hook == DSPHOOK_ONCANCEL) {
+        contextLock(audio_device);
+        audio_device->hidden->isCancelled = true;
+        SDL_AudioDeviceDisconnected(audio_device);
+        CondVar_Broadcast(&audio_device->hidden->cv);
+        contextUnlock(audio_device);
+    }
+}
+
+static void AudioFrameFinished(void *vdevice)
+{
+    bool shouldBroadcast = false;
+    unsigned i;
+    SDL_AudioDevice *device = (SDL_AudioDevice *)vdevice;
+
+    contextLock(device);
+
+    for (i = 0; i < NUM_BUFFERS; i++) {
+        if (device->hidden->waveBuf[i].status == NDSP_WBUF_DONE) {
+            device->hidden->waveBuf[i].status = NDSP_WBUF_FREE;
+            shouldBroadcast = true;
+        }
+    }
+
+    if (shouldBroadcast) {
+        CondVar_Broadcast(&device->hidden->cv);
+    }
+
+    contextUnlock(device);
+}
+
+static bool N3DSAUDIO_OpenDevice(SDL_AudioDevice *device)
+{
+    Result ndsp_init_res;
+    Uint8 *data_vaddr;
+    float mix[12];
+
+    device->hidden = (struct SDL_PrivateAudioData *)SDL_calloc(1, sizeof(*device->hidden));
+    if (!device->hidden) {
+        return false;
+    }
+
+    // Initialise the DSP service
+    ndsp_init_res = ndspInit();
+    if (R_FAILED(ndsp_init_res)) {
+        if ((R_SUMMARY(ndsp_init_res) == RS_NOTFOUND) && (R_MODULE(ndsp_init_res) == RM_DSP)) {
+            return SDL_SetError("DSP init failed: dspfirm.cdc missing!");
+        } else {
+            return SDL_SetError("DSP init failed. Error code: 0x%lX", ndsp_init_res);
+        }
+    }
+
+    // Initialise internal state
+    LightLock_Init(&device->hidden->lock);
+    CondVar_Init(&device->hidden->cv);
+
+    if (device->spec.channels > 2) {
+        device->spec.channels = 2;
+    }
+
+    Uint32 format = 0;
+    SDL_AudioFormat test_format;
+    const SDL_AudioFormat *closefmts = SDL_ClosestAudioFormats(device->spec.format);
+    while ((test_format = *(closefmts++)) != 0) {
+        if (test_format == SDL_AUDIO_S8) {  // Signed 8-bit audio supported
+            format = (device->spec.channels == 2) ? NDSP_FORMAT_STEREO_PCM8 : NDSP_FORMAT_MONO_PCM8;
+            break;
+        } else if (test_format == SDL_AUDIO_S16) {  // Signed 16-bit audio supported
+            format = (device->spec.channels == 2) ? NDSP_FORMAT_STEREO_PCM16 : NDSP_FORMAT_MONO_PCM16;
+            break;
+        }
+    }
+
+    if (!test_format) {      // shouldn't happen, but just in case...
+        return SDL_SetError("No supported audio format found.");
+    }
+
+    device->spec.format = test_format;
+
+    // Update the fragment size as size in bytes
+    SDL_UpdatedAudioDeviceFormat(device);
+
+    // Allocate mixing buffer
+    if (device->buffer_size >= SDL_MAX_UINT32 / 2) {
+        return SDL_SetError("Mixing buffer is too large.");
+    }
+
+    device->hidden->mixbuf = (Uint8 *)SDL_malloc(device->buffer_size);
+    if (!device->hidden->mixbuf) {
+        return false;
+    }
+
+    SDL_memset(device->hidden->mixbuf, device->silence_value, device->buffer_size);
+
+    data_vaddr = (Uint8 *)linearAlloc(device->buffer_size * NUM_BUFFERS);
+    if (!data_vaddr) {
+        return SDL_OutOfMemory();
+    }
+
+    SDL_memset(data_vaddr, 0, device->buffer_size * NUM_BUFFERS);
+    DSP_FlushDataCache(data_vaddr, device->buffer_size * NUM_BUFFERS);
+
+    device->hidden->nextbuf = 0;
+
+    ndspChnReset(0);
+
+    ndspChnSetInterp(0, NDSP_INTERP_LINEAR);
+    ndspChnSetRate(0, device->spec.freq);
+    ndspChnSetFormat(0, format);
+
+    SDL_zeroa(mix);
+    mix[0] = mix[1] = 1.0f;
+    ndspChnSetMix(0, mix);
+
+    SDL_memset(device->hidden->waveBuf, 0, sizeof(ndspWaveBuf) * NUM_BUFFERS);
+
+    const int sample_frame_size = SDL_AUDIO_FRAMESIZE(device->spec);
+    for (unsigned i = 0; i < NUM_BUFFERS; i++) {
+        device->hidden->waveBuf[i].data_vaddr = data_vaddr;
+        device->hidden->waveBuf[i].nsamples = device->buffer_size / sample_frame_size;
+        data_vaddr += device->buffer_size;
+    }
+
+    // Setup callback
+    audio_device = device;
+    ndspSetCallback(AudioFrameFinished, device);
+    dspHook(&dsp_hook, N3DSAUD_DspHook);
+
+    return true;
+}
+
+static bool N3DSAUDIO_PlayDevice(SDL_AudioDevice *device, const Uint8 *buffer, int buflen)
+{
+    contextLock(device);
+
+    const size_t nextbuf = device->hidden->nextbuf;
+
+    if (device->hidden->isCancelled ||
+        device->hidden->waveBuf[nextbuf].status != NDSP_WBUF_FREE) {
+        contextUnlock(device);
+        return true;  // !!! FIXME: is this a fatal error? If so, this should return false.
+    }
+
+    device->hidden->nextbuf = (nextbuf + 1) % NUM_BUFFERS;
+
+    contextUnlock(device);
+
+    SDL_memcpy((void *)device->hidden->waveBuf[nextbuf].data_vaddr, buffer, buflen);
+    DSP_FlushDataCache(device->hidden->waveBuf[nextbuf].data_vaddr, buflen);
+
+    ndspChnWaveBufAdd(0, &device->hidden->waveBuf[nextbuf]);
+
+    return true;
+}
+
+static bool N3DSAUDIO_WaitDevice(SDL_AudioDevice *device)
+{
+    contextLock(device);
+    while (!device->hidden->isCancelled && !SDL_GetAtomicInt(&device->shutdown) &&
+           device->hidden->waveBuf[device->hidden->nextbuf].status != NDSP_WBUF_FREE) {
+        CondVar_Wait(&device->hidden->cv, &device->hidden->lock);
+    }
+    contextUnlock(device);
+    return true;
+}
+
+static Uint8 *N3DSAUDIO_GetDeviceBuf(SDL_AudioDevice *device, int *buffer_size)
+{
+    return device->hidden->mixbuf;
+}
+
+static void N3DSAUDIO_CloseDevice(SDL_AudioDevice *device)
+{
+    if (!device->hidden) {
+        return;
+    }
+
+    contextLock(device);
+
+    dspUnhook(&dsp_hook);
+    ndspSetCallback(NULL, NULL);
+
+    if (!device->hidden->isCancelled) {
+        ndspChnReset(0);
+        SDL_memset(device->hidden->waveBuf, 0, sizeof(ndspWaveBuf) * NUM_BUFFERS);
+        CondVar_Broadcast(&device->hidden->cv);
+    }
+
+    contextUnlock(device);
+
+    ndspExit();
+
+    if (device->hidden->waveBuf[0].data_vaddr) {
+        linearFree((void *)device->hidden->waveBuf[0].data_vaddr);
+    }
+
+    if (device->hidden->mixbuf) {
+        SDL_free(device->hidden->mixbuf);
+        device->hidden->mixbuf = NULL;
+    }
+
+    SDL_free(device->hidden);
+    device->hidden = NULL;
+}
+
+static void N3DSAUDIO_ThreadInit(SDL_AudioDevice *device)
+{
+    s32 current_priority = 0x30;
+    svcGetThreadPriority(&current_priority, CUR_THREAD_HANDLE);
+    current_priority--;
+    // 0x18 is reserved for video, 0x30 is the default for main thread
+    current_priority = SDL_clamp(current_priority, 0x19, 0x2F);
+    svcSetThreadPriority(CUR_THREAD_HANDLE, current_priority);
+}
+
+static bool N3DSAUDIO_Init(SDL_AudioDriverImpl *impl)
+{
+    impl->OpenDevice = N3DSAUDIO_OpenDevice;
+    impl->PlayDevice = N3DSAUDIO_PlayDevice;
+    impl->WaitDevice = N3DSAUDIO_WaitDevice;
+    impl->GetDeviceBuf = N3DSAUDIO_GetDeviceBuf;
+    impl->CloseDevice = N3DSAUDIO_CloseDevice;
+    impl->ThreadInit = N3DSAUDIO_ThreadInit;
+    impl->OnlyHasDefaultPlaybackDevice = true;
+
+    // Should be possible, but micInit would fail
+    impl->HasRecordingSupport = false;
+
+    return true;
+}
+
+AudioBootStrap N3DSAUDIO_bootstrap = {
+    N3DSAUDIO_DRIVER_NAME,
+    "SDL N3DS audio driver",
+    N3DSAUDIO_Init,
+    false,
+    false
+};
+
+#endif // SDL_AUDIO_DRIVER_N3DS
diff --git a/contrib/SDL-3.2.8/src/audio/n3ds/SDL_n3dsaudio.h b/contrib/SDL-3.2.8/src/audio/n3ds/SDL_n3dsaudio.h
new file mode 100644
index 0000000..c9ae4f8
--- /dev/null
+++ b/contrib/SDL-3.2.8/src/audio/n3ds/SDL_n3dsaudio.h
@@ -0,0 +1,40 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef SDL_n3dsaudio_h
+#define SDL_n3dsaudio_h
+
+#include <3ds.h>
+
+#define NUM_BUFFERS 3 // -- Minimum 2!
+
+struct SDL_PrivateAudioData
+{
+    // Speaker data
+    Uint8 *mixbuf;
+    Uint32 nextbuf;
+    ndspWaveBuf waveBuf[NUM_BUFFERS];
+    LightLock lock;
+    CondVar cv;
+    bool isCancelled;
+};
+
+#endif // SDL_n3dsaudio_h