x86: hpeldsp: mark _xy2 versions as approximate

Currently, only the mmx version is bitexact, the others (mmxext and
3dnow) are not, in spite of their naming.

Therefore, make their name more obvious. Also restore a comment that
was removed in 71155d7b.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/x86/hpeldsp.asm

@@ -451,8 +451,10 @@ AVG_PIXELS8_Y2
 
 
 ; void ff_avg_pixels8_xy2(uint8_t *block, const uint8_t *pixels, ptrdiff_t line_size, int h)
-%macro AVG_PIXELS8_XY2 0
-cglobal avg_pixels8_xy2, 4,5
+; Note this is not correctly rounded, and is therefore used for
+; not-bitexact output
+%macro AVG_APPROX_PIXELS8_XY2 0
+cglobal avg_approx_pixels8_xy2, 4,5
     mova         m6, [pb_1]
     lea          r4, [r2*2]
     mova         m0, [r1]
@@ -489,6 +491,6 @@ cglobal avg_pixels8_xy2, 4,5
 %endmacro
 
 INIT_MMX mmxext
-AVG_PIXELS8_XY2
+AVG_APPROX_PIXELS8_XY2
 INIT_MMX 3dnow
-AVG_PIXELS8_XY2
+AVG_APPROX_PIXELS8_XY2

libavcodec/x86/hpeldsp_init.c

@@ -74,10 +74,10 @@ void ff_avg_pixels8_y2_mmxext(uint8_t *block, const uint8_t *pixels,
                               ptrdiff_t line_size, int h);
 void ff_avg_pixels8_y2_3dnow(uint8_t *block, const uint8_t *pixels,
                              ptrdiff_t line_size, int h);
-void ff_avg_pixels8_xy2_mmxext(uint8_t *block, const uint8_t *pixels,
-                               ptrdiff_t line_size, int h);
-void ff_avg_pixels8_xy2_3dnow(uint8_t *block, const uint8_t *pixels,
-                              ptrdiff_t line_size, int h);
+void ff_avg_approx_pixels8_xy2_mmxext(uint8_t *block, const uint8_t *pixels,
+                                      ptrdiff_t line_size, int h);
+void ff_avg_approx_pixels8_xy2_3dnow(uint8_t *block, const uint8_t *pixels,
+                                     ptrdiff_t line_size, int h);
 
 #define avg_pixels8_mmx         ff_avg_pixels8_mmx
 #define avg_pixels8_x2_mmx      ff_avg_pixels8_x2_mmx
@@ -156,7 +156,7 @@ CALL_2X_PIXELS_EXPORT(ff_put_pixels16_xy2_mmx, ff_put_pixels8_xy2_mmx, 8)
     CALL_2X_PIXELS(avg_pixels16           ## CPUEXT, ff_avg_pixels8           ## CPUEXT, 8) \
     CALL_2X_PIXELS(avg_pixels16_x2        ## CPUEXT, ff_avg_pixels8_x2        ## CPUEXT, 8) \
     CALL_2X_PIXELS(avg_pixels16_y2        ## CPUEXT, ff_avg_pixels8_y2        ## CPUEXT, 8) \
-    CALL_2X_PIXELS(avg_pixels16_xy2       ## CPUEXT, ff_avg_pixels8_xy2       ## CPUEXT, 8)
+    CALL_2X_PIXELS(avg_approx_pixels16_xy2## CPUEXT, ff_avg_approx_pixels8_xy2## CPUEXT, 8)
 
 HPELDSP_AVG_PIXELS16(_3dnow)
 HPELDSP_AVG_PIXELS16(_mmxext)
@@ -223,8 +223,8 @@ static void hpeldsp_init_mmxext(HpelDSPContext *c, int flags, int cpu_flags)
         c->put_no_rnd_pixels_tab[1][1] = ff_put_no_rnd_pixels8_x2_mmxext;
         c->put_no_rnd_pixels_tab[1][2] = ff_put_no_rnd_pixels8_y2_mmxext;
 
-        c->avg_pixels_tab[0][3] = avg_pixels16_xy2_mmxext;
-        c->avg_pixels_tab[1][3] = ff_avg_pixels8_xy2_mmxext;
+        c->avg_pixels_tab[0][3] = avg_approx_pixels16_xy2_mmxext;
+        c->avg_pixels_tab[1][3] = ff_avg_approx_pixels8_xy2_mmxext;
     }
 
     if (flags & CODEC_FLAG_BITEXACT && CONFIG_VP3_DECODER) {
@@ -257,8 +257,8 @@ static void hpeldsp_init_3dnow(HpelDSPContext *c, int flags, int cpu_flags)
         c->put_no_rnd_pixels_tab[1][1] = ff_put_no_rnd_pixels8_x2_3dnow;
         c->put_no_rnd_pixels_tab[1][2] = ff_put_no_rnd_pixels8_y2_3dnow;
 
-        c->avg_pixels_tab[0][3] = avg_pixels16_xy2_3dnow;
-        c->avg_pixels_tab[1][3] = ff_avg_pixels8_xy2_3dnow;
+        c->avg_pixels_tab[0][3] = avg_approx_pixels16_xy2_3dnow;
+        c->avg_pixels_tab[1][3] = ff_avg_approx_pixels8_xy2_3dnow;
     }
 
     if (flags & CODEC_FLAG_BITEXACT && CONFIG_VP3_DECODER) {