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Isolate the Altivec code so non-Altivec PPC targets can use the same binary.

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Moved all the code using Altivec intrinsics to separate files. This 
means we can optionally use GCC's -maltivec on just these files, which
are chosen at runtime if the CPU supports Altivec, and compile the rest
without it, making a single binary that has Altivec optimizations but
can still work on G3.

Unlike SSE and similar extensions on x86, there does not seem to be
a way to enable conditional, targeted use of Altivec based on runtime
detection (which is what ioquake3 wants to do) without also giving the
compiler permission to use Altivec in code generation; so to not crash
on CPUs that do not implement Altivec, we'll have to turn it off
altogether, except in translation units that are only entered when
runtime Altivec detection is successful.

This has been tested on Linux PPC (on an Altivec-enabled CPU),
but we may need further work after testing trickles out to other
PowerPC devices and ancient Mac OS X builds.

I did a little work on this patch, but the majority of the effort belongs 
to Simon McVittie (thanks!).
This commit is contained in:
Simon McVittie 2018-05-12 19:14:47 +01:00 • committed by Ryan C. Gordon
parent 2326a060b9
commit 5909b9a1cf
12 changed files with 686 additions and 607 deletions
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76
code/renderergl1/tr_shade_calc.c
View file

@ -22,9 +22,6 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
// tr_shade_calc.c
#include "tr_local.h"
#if idppc_altivec && !defined(__APPLE__)
#include <altivec.h>
#endif
#define WAVEVALUE( table, base, amplitude, phase, freq ) ((base) + table[ ( (int64_t) ( ( (phase) + tess.shaderTime * (freq) ) * FUNCTABLE_SIZE ) ) & FUNCTABLE_MASK ] * (amplitude))
@ -1082,77 +1079,6 @@ void RB_CalcSpecularAlpha( unsigned char *alphas ) {
**
** The basic vertex lighting calc
*/
#if idppc_altivec
static void RB_CalcDiffuseColor_altivec( unsigned char *colors )
{
int i;
float *v, *normal;
trRefEntity_t *ent;
int ambientLightInt;
vec3_t lightDir;
int numVertexes;
vector unsigned char vSel = VECCONST_UINT8(0x00, 0x00, 0x00, 0xff,
0x00, 0x00, 0x00, 0xff,
0x00, 0x00, 0x00, 0xff,
0x00, 0x00, 0x00, 0xff);
vector float ambientLightVec;
vector float directedLightVec;
vector float lightDirVec;
vector float normalVec0, normalVec1;
vector float incomingVec0, incomingVec1, incomingVec2;
vector float zero, jVec;
vector signed int jVecInt;
vector signed short jVecShort;
vector unsigned char jVecChar, normalPerm;
ent = backEnd.currentEntity;
ambientLightInt = ent->ambientLightInt;
// A lot of this could be simplified if we made sure
// entities light info was 16-byte aligned.
jVecChar = vec_lvsl(0, ent->ambientLight);
ambientLightVec = vec_ld(0, (vector float *)ent->ambientLight);
jVec = vec_ld(11, (vector float *)ent->ambientLight);
ambientLightVec = vec_perm(ambientLightVec,jVec,jVecChar);
jVecChar = vec_lvsl(0, ent->directedLight);
directedLightVec = vec_ld(0,(vector float *)ent->directedLight);
jVec = vec_ld(11,(vector float *)ent->directedLight);
directedLightVec = vec_perm(directedLightVec,jVec,jVecChar);
jVecChar = vec_lvsl(0, ent->lightDir);
lightDirVec = vec_ld(0,(vector float *)ent->lightDir);
jVec = vec_ld(11,(vector float *)ent->lightDir);
lightDirVec = vec_perm(lightDirVec,jVec,jVecChar);
zero = (vector float)vec_splat_s8(0);
VectorCopy( ent->lightDir, lightDir );
v = tess.xyz[0];
normal = tess.normal[0];
normalPerm = vec_lvsl(0,normal);
numVertexes = tess.numVertexes;
for (i = 0 ; i < numVertexes ; i++, v += 4, normal += 4) {
normalVec0 = vec_ld(0,(vector float *)normal);
normalVec1 = vec_ld(11,(vector float *)normal);
normalVec0 = vec_perm(normalVec0,normalVec1,normalPerm);
incomingVec0 = vec_madd(normalVec0, lightDirVec, zero);
incomingVec1 = vec_sld(incomingVec0,incomingVec0,4);
incomingVec2 = vec_add(incomingVec0,incomingVec1);
incomingVec1 = vec_sld(incomingVec1,incomingVec1,4);
incomingVec2 = vec_add(incomingVec2,incomingVec1);
incomingVec0 = vec_splat(incomingVec2,0);
incomingVec0 = vec_max(incomingVec0,zero);
normalPerm = vec_lvsl(12,normal);
jVec = vec_madd(incomingVec0, directedLightVec, ambientLightVec);
jVecInt = vec_cts(jVec,0); // RGBx
jVecShort = vec_pack(jVecInt,jVecInt); // RGBxRGBx
jVecChar = vec_packsu(jVecShort,jVecShort); // RGBxRGBxRGBxRGBx
jVecChar = vec_sel(jVecChar,vSel,vSel); // RGBARGBARGBARGBA replace alpha with 255
vec_ste((vector unsigned int)jVecChar,0,(unsigned int *)&colors[i*4]); // store color
}
}
#endif
static void RB_CalcDiffuseColor_scalar( unsigned char *colors )
{
int i, j;
@ -1206,7 +1132,7 @@ void RB_CalcDiffuseColor( unsigned char *colors )
{
#if idppc_altivec
if (com_altivec->integer) {
// must be in a separate function or G3 systems will crash.
// must be in a separate translation unit or G3 systems will crash.
RB_CalcDiffuseColor_altivec( colors );
return;
}