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Assume you have SSE1 if you're using a compiler that can generate SSE…
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… code.

(SSE1 has been around since the Pentium III, released in 1999. Intel users:
you probably have it!)
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@icculus
icculus committed Apr 24, 2018
1 parent bd23b65 commit 52b3119
Showing 1 changed file with 38 additions and 26 deletions.
64 changes: 38 additions & 26 deletions mojoal.c
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Expand Up @@ -167,6 +167,11 @@
#define SIMDALIGNEDSTRUCT struct
#endif

#ifdef __SSE__ /* if you are on x86 or x86-64, we assume you have SSE1 by now. */
#define NEED_SCALAR_FALLBACK 0
#else
#define NEED_SCALAR_FALLBACK 1
#endif

/* lifted this ring buffer code from my al_osx project; I wrote it all, so it's stealable. */
typedef struct
Expand Down Expand Up @@ -382,9 +387,6 @@ struct ALCcontext_struct
ALCcontext *next;
};

#ifdef __SSE__
static int has_sse = 0;
#endif

/* ALC implementation... */

Expand Down Expand Up @@ -423,7 +425,10 @@ ALCdevice *alcOpenDevice(const ALCchar *devicename)
}

#ifdef __SSE__
has_sse = SDL_HasSSE();
if (!SDL_HasSSE()) {
SDL_QuitSubSystem(SDL_INIT_AUDIO);
return NULL; /* whoa! Better order a new Pentium III from Gateway 2000! */
}
#endif

dev = (ALCdevice *) SDL_calloc(1, sizeof (ALCdevice));
Expand Down Expand Up @@ -668,7 +673,6 @@ static void mix_float32_c2_scalar(const ALfloat * restrict panning, const float
}
}


#ifdef __SSE__
static void mix_float32_c1_sse(const ALfloat * restrict panning, const float * restrict data, float * restrict stream, const ALsizei mixframes)
{
Expand Down Expand Up @@ -909,6 +913,7 @@ static ALCboolean mix_source_buffer_queue(ALCcontext *ctx, ALsource *src, Buffer
Basically takes two vectors and gives you a vector that's perpendicular
to both.
*/
#if NEED_SCALAR_FALLBACK
static void xyzzy(ALfloat *v, const ALfloat *a, const ALfloat *b)
{
v[0] = (a[1] * b[2]) - (a[2] * b[1]);
Expand Down Expand Up @@ -943,6 +948,7 @@ static void normalize(ALfloat *v)
v[2] /= mag;
}
}
#endif

#ifdef __SSE__
static __m128 xyzzy_sse(const __m128 a, const __m128 b)
Expand Down Expand Up @@ -1048,12 +1054,15 @@ static void calculate_channel_gains(const ALCcontext *ctx, const ALsource *src,
ALfloat distance;
ALfloat gain;
ALfloat radians;
ALfloat position[3];

#ifdef __SSE__
__m128 position_sse;
#endif

#if NEED_SCALAR_FALLBACK
ALfloat position[3];
#endif

/* this goes through the steps the AL spec dictates for gain and distance attenuation... */

if (!spatialize) {
Expand All @@ -1064,25 +1073,24 @@ static void calculate_channel_gains(const ALCcontext *ctx, const ALsource *src,
}

#ifdef __SSE__
if (has_sse) {
position_sse = _mm_load_ps(src->position);
/* if values aren't source-relative, then convert it to be so. */
if (!src->source_relative) {
position_sse = _mm_sub_ps(position_sse, _mm_load_ps(ctx->listener.position));
}
distance = magnitude_sse(position_sse);
} else
position_sse = _mm_load_ps(src->position);
/* if values aren't source-relative, then convert it to be so. */
if (!src->source_relative) {
position_sse = _mm_sub_ps(position_sse, _mm_load_ps(ctx->listener.position));
}
distance = magnitude_sse(position_sse);
#endif
{
SDL_memcpy(position, src->position, sizeof (position));
/* if values aren't source-relative, then convert it to be so. */
if (!src->source_relative) {
position[0] -= ctx->listener.position[0];
position[1] -= ctx->listener.position[1];
position[2] -= ctx->listener.position[2];
}
distance = magnitude(position);

#if NEED_SCALAR_FALLBACK
SDL_memcpy(position, src->position, sizeof (position));
/* if values aren't source-relative, then convert it to be so. */
if (!src->source_relative) {
position[0] -= ctx->listener.position[0];
position[1] -= ctx->listener.position[1];
position[2] -= ctx->listener.position[2];
}
distance = magnitude(position);
#endif

/* AL SPEC: ""1. Distance attenuation is calculated first, including
minimum (AL_REFERENCE_DISTANCE) and maximum (AL_MAX_DISTANCE)
Expand Down Expand Up @@ -1135,8 +1143,9 @@ static void calculate_channel_gains(const ALCcontext *ctx, const ALsource *src,
XYZZY!! https://en.wikipedia.org/wiki/Cross_product#Mnemonic
*/
#ifdef __SSE__
if (has_sse) { /* (the math is explained in the scalar version.) */

#ifdef __SSE__ /* (the math is explained in the scalar version.) */
{
const __m128 at_sse = _mm_load_ps(at);
const __m128 U_sse = normalize_sse(xyzzy_sse(at_sse, _mm_load_ps(up)));
const __m128 V_sse = xyzzy_sse(at_sse, U_sse);
Expand All @@ -1153,8 +1162,10 @@ static void calculate_channel_gains(const ALCcontext *ctx, const ALsource *src,
if (_mm_comilt_ss(rotated_sse, _mm_setzero_ps())) {
radians = -radians;
}
} else
}
#endif

#if NEED_SCALAR_FALLBACK
{
ALfloat U[3];
ALfloat V[3];
Expand Down Expand Up @@ -1198,6 +1209,7 @@ static void calculate_channel_gains(const ALCcontext *ctx, const ALsource *src,
radians = -radians;
}
}
#endif

/* here comes the Constant Power Panning magic... */
#define SQRT2_DIV2 0.7071067812f /* sqrt(2.0) / 2.0 ... */
Expand Down

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