ppc: dsputil: comment formatting and wording/grammar improvements

libavcodec/ppc/dsputil_ppc.c

@@ -32,24 +32,23 @@
 
 /* ***** WARNING ***** WARNING ***** WARNING ***** */
 /*
-clear_blocks_dcbz32_ppc will not work properly on PowerPC processors with a
-cache line size not equal to 32 bytes.
-Fortunately all processor used by Apple up to at least the 7450 (aka second
-generation G4) use 32 bytes cache line.
-This is due to the use of the 'dcbz' instruction. It simply clear to zero a
-single cache line, so you need to know the cache line size to use it !
-It's absurd, but it's fast...
-
-update 24/06/2003 : Apple released yesterday the G5, with a PPC970. cache line
-size: 128 bytes. Oups.
-The semantic of dcbz was changed, it always clear 32 bytes. so the function
-below will work, but will be slow. So I fixed check_dcbz_effect to use dcbzl,
-which is defined to clear a cache line (as dcbz before). So we still can
-distinguish, and use dcbz (32 bytes) or dcbzl (one cache line) as required.
-
-see <http://developer.apple.com/technotes/tn/tn2087.html>
-and <http://developer.apple.com/technotes/tn/tn2086.html>
-*/
+ * clear_blocks_dcbz32_ppc will not work properly on PowerPC processors with
+ * a cache line size not equal to 32 bytes. Fortunately all processors used
+ * by Apple up to at least the 7450 (AKA second generation G4) use 32-byte
+ * cache lines. This is due to the use of the 'dcbz' instruction. It simply
+ * clears a single cache line to zero, so you need to know the cache line
+ * size to use it! It's absurd, but it's fast...
+ *
+ * update 24/06/2003: Apple released the G5 yesterday, with a PPC970.
+ * cache line size: 128 bytes. Oups.
+ * The semantics of dcbz was changed, it always clears 32 bytes. So the function
+ * below will work, but will be slow. So I fixed check_dcbz_effect to use dcbzl,
+ * which is defined to clear a cache line (as dcbz before). So we can still
+ * distinguish, and use dcbz (32 bytes) or dcbzl (one cache line) as required.
+ *
+ * see <http://developer.apple.com/technotes/tn/tn2087.html>
+ * and <http://developer.apple.com/technotes/tn/tn2086.html>
+ */
 static void clear_blocks_dcbz32_ppc(int16_t *blocks)
 {
     register int misal = ((unsigned long)blocks & 0x00000010);
@@ -73,17 +72,17 @@ static void clear_blocks_dcbz32_ppc(int16_t *blocks)
     }
 }
 
-/* same as above, when dcbzl clear a whole 128B cache line
-   i.e. the PPC970 aka G5 */
+/* Same as above, when dcbzl clears a whole 128 bytes cache line
+ * i.e. the PPC970 AKA G5. */
 #if HAVE_DCBZL
 static void clear_blocks_dcbz128_ppc(int16_t *blocks)
 {
     register int misal = ((unsigned long)blocks & 0x0000007f);
     register int i = 0;
     if (misal) {
-        // we could probably also optimize this case,
-        // but there's not much point as the machines
-        // aren't available yet (2003-06-26)
+        /* We could probably also optimize this case,
+         * but there's not much point as the machines
+         * aren't available yet (2003-06-26). */
         memset(blocks, 0, sizeof(int16_t)*6*64);
     }
     else
@@ -99,11 +98,10 @@ static void clear_blocks_dcbz128_ppc(int16_t *blocks)
 #endif
 
 #if HAVE_DCBZL
-/* check dcbz report how many bytes are set to 0 by dcbz */
-/* update 24/06/2003 : replace dcbz by dcbzl to get
-   the intended effect (Apple "fixed" dcbz)
-   unfortunately this cannot be used unless the assembler
-   knows about dcbzl ... */
+/* Check dcbz report how many bytes are set to 0 by dcbz. */
+/* update 24/06/2003: Replace dcbz by dcbzl to get the intended effect
+ * (Apple "fixed" dcbz). Unfortunately this cannot be used unless the
+ * assembler knows about dcbzl ... */
 static long check_dcbzl_effect(void)
 {
     register char *fakedata = av_malloc(1024);
@@ -120,8 +118,8 @@ static long check_dcbzl_effect(void)
 
     memset(fakedata, 0xFF, 1024);
 
-    /* below the constraint "b" seems to mean "Address base register"
-       in gcc-3.3 / RS/6000 speaks. seems to avoid using r0, so.... */
+    /* Below the constraint "b" seems to mean "address base register"
+     * in gcc-3.3 / RS/6000 speaks. Seems to avoid using r0, so.... */
     __asm__ volatile("dcbzl %0, %1" : : "b" (fakedata_middle), "r" (zero));
 
     for (i = 0; i < 1024 ; i ++) {
@@ -144,7 +142,7 @@ av_cold void ff_dsputil_init_ppc(DSPContext *c, AVCodecContext *avctx)
 {
     const int high_bit_depth = avctx->bits_per_raw_sample > 8;
 
-    // Common optimizations whether AltiVec is available or not
+    // common optimizations whether AltiVec is available or not
     if (!high_bit_depth) {
     switch (check_dcbzl_effect()) {
         case 32:

libavcodec/ppc/fdct_altivec.c

@@ -259,11 +259,10 @@ void ff_fdct_altivec(int16_t *block)
 #undef MERGE_S16
     /* }}} */
 
+    /* Some of the initial calculations can be done as vector short
+     * before conversion to vector float.  The following code section
+     * takes advantage of this. */
 
-/* Some of the initial calculations can be done as vector short before
- * conversion to vector float.  The following code section takes advantage
- * of this.
- */
     /* fdct rows {{{ */
     x0 = ((vector float)vec_add(vs16(b00), vs16(b70)));
     x7 = ((vector float)vec_sub(vs16(b00), vs16(b70)));

libavcodec/ppc/fft_altivec.c

@@ -27,12 +27,12 @@
 #include "libavcodec/fft.h"
 
 /**
- * Do a complex FFT with the parameters defined in ff_fft_init(). The
- * input data must be permuted before with s->revtab table. No
- * 1.0/sqrt(n) normalization is done.
- * AltiVec-enabled
- * This code assumes that the 'z' pointer is 16 bytes-aligned
- * It also assumes all FFTComplex are 8 bytes-aligned pair of float
+ * Do a complex FFT with the parameters defined in ff_fft_init().
+ * The input data must be permuted before with s->revtab table.
+ * No 1.0 / sqrt(n) normalization is done.
+ * AltiVec-enabled:
+ * This code assumes that the 'z' pointer is 16 bytes-aligned.
+ * It also assumes all FFTComplex are 8 bytes-aligned pairs of floats.
  */
 
 void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z);

libavcodec/ppc/gmc_altivec.c

 /*
- * GMC (Global Motion Compensation)
- * AltiVec-enabled
+ * GMC (Global Motion Compensation), AltiVec-enabled
+ *
  * Copyright (c) 2003 Romain Dolbeau <romain@dolbeau.org>
  *
  * This file is part of Libav.
@@ -25,10 +25,8 @@
 #include "libavutil/ppc/util_altivec.h"
 #include "dsputil_altivec.h"
 
-/*
-  altivec-enhanced gmc1. ATM this code assume stride is a multiple of 8,
-  to preserve proper dst alignment.
-*/
+/* AltiVec-enhanced gmc1. ATM this code assumes stride is a multiple of 8
+ * to preserve proper dst alignment. */
 void ff_gmc1_altivec(uint8_t *dst /* align 8 */, uint8_t *src /* align1 */, int stride, int h, int x16, int y16, int rounder)
 {
     const DECLARE_ALIGNED(16, unsigned short, rounder_a) = rounder;
@@ -56,18 +54,16 @@ void ff_gmc1_altivec(uint8_t *dst /* align 8 */, uint8_t *src /* align1 */, int
 
     rounderV = vec_splat((vec_u16)vec_lde(0, &rounder_a), 0);
 
-    // we'll be able to pick-up our 9 char elements
-    // at src from those 32 bytes
-    // we load the first batch here, as inside the loop
-    // we can re-use 'src+stride' from one iteration
-    // as the 'src' of the next.
+    /* we'll be able to pick-up our 9 char elements at src from those
+     * 32 bytes we load the first batch here, as inside the loop we can
+     * reuse 'src + stride' from one iteration as the 'src' of the next. */
     src_0 = vec_ld(0, src);
     src_1 = vec_ld(16, src);
     srcvA = vec_perm(src_0, src_1, vec_lvsl(0, src));
 
     if (src_really_odd != 0x0000000F) {
-        // if src & 0xF == 0xF, then (src+1) is properly aligned
-        // on the second vector.
+        /* If src & 0xF == 0xF, then (src + 1) is properly aligned
+         * on the second vector. */
         srcvB = vec_perm(src_0, src_1, vec_lvsl(1, src));
     } else {
         srcvB = src_1;
@@ -81,17 +77,16 @@ void ff_gmc1_altivec(uint8_t *dst /* align 8 */, uint8_t *src /* align1 */, int
 
         dstv = vec_ld(0, dst);
 
-        // we we'll be able to pick-up our 9 char elements
-        // at src + stride from those 32 bytes
-        // then reuse the resulting 2 vectors srvcC and srcvD
-        // as the next srcvA and srcvB
+        /* We'll be able to pick-up our 9 char elements at src + stride from
+         * those 32 bytes then reuse the resulting 2 vectors srvcC and srcvD
+         * as the next srcvA and srcvB. */
         src_0 = vec_ld(stride + 0, src);
         src_1 = vec_ld(stride + 16, src);
         srcvC = vec_perm(src_0, src_1, vec_lvsl(stride + 0, src));
 
         if (src_really_odd != 0x0000000F) {
-            // if src & 0xF == 0xF, then (src+1) is properly aligned
-            // on the second vector.
+            /* If src & 0xF == 0xF, then (src + 1) is properly aligned
+             * on the second vector. */
             srcvD = vec_perm(src_0, src_1, vec_lvsl(stride + 1, src));
         } else {
             srcvD = src_1;
@@ -100,10 +95,9 @@ void ff_gmc1_altivec(uint8_t *dst /* align 8 */, uint8_t *src /* align1 */, int
         srcvC = vec_mergeh(vczero, srcvC);
         srcvD = vec_mergeh(vczero, srcvD);
 
-
-        // OK, now we (finally) do the math :-)
-        // those four instructions replaces 32 int muls & 32 int adds.
-        // isn't AltiVec nice ?
+        /* OK, now we (finally) do the math :-)
+         * Those four instructions replace 32 int muls & 32 int adds.
+         * Isn't AltiVec nice? */
         tempA = vec_mladd((vector unsigned short)srcvA, Av, rounderV);
         tempB = vec_mladd((vector unsigned short)srcvB, Bv, tempA);
         tempC = vec_mladd((vector unsigned short)srcvC, Cv, tempB);

libavcodec/ppc/idct_altivec.c

@@ -18,24 +18,19 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-/*
- * NOTE: This code is based on GPL code from the libmpeg2 project.  The
+/* NOTE: This code is based on GPL code from the libmpeg2 project.  The
  * author, Michel Lespinasses, has given explicit permission to release
  * under LGPL as part of Libav.
- */
-
-/*
+ *
  * Libav integration by Dieter Shirley
  *
  * This file is a direct copy of the AltiVec IDCT module from the libmpeg2
  * project.  I've deleted all of the libmpeg2-specific code, renamed the
  * functions and reordered the function parameters.  The only change to the
  * IDCT function itself was to factor out the partial transposition, and to
- * perform a full transpose at the end of the function.
- */
-
+ * perform a full transpose at the end of the function. */
 
-#include <stdlib.h>                                      /* malloc(), free() */
+#include <stdlib.h>
 #include <string.h>
 #include "config.h"
 #if HAVE_ALTIVEC_H

libavcodec/ppc/int_altivec.c

@@ -19,9 +19,9 @@
  */
 
 /**
- ** @file
- ** integer misc ops.
- **/
+ * @file
+ * miscellaneous integer operations
+ */
 
 #include "config.h"
 #if HAVE_ALTIVEC_H
@@ -43,8 +43,8 @@ static int ssd_int8_vs_int16_altivec(const int8_t *pix1, const int16_t *pix2,
             int32_t score[4];
           } u;
     u.vscore = vec_splat_s32(0);
-//
-//XXX lazy way, fix it later
+
+// XXX lazy way, fix it later
 
 #define vec_unaligned_load(b) \
     vec_perm(vec_ld(0,b),vec_ld(15,b),vec_lvsl(0, b));
@@ -52,12 +52,12 @@ static int ssd_int8_vs_int16_altivec(const int8_t *pix1, const int16_t *pix2,
     size16 = size >> 4;
     while(size16) {
 //        score += (pix1[i]-pix2[i])*(pix1[i]-pix2[i]);
-        //load pix1 and the first batch of pix2
+        // load pix1 and the first batch of pix2
 
         vpix1 = vec_unaligned_load(pix1);
         vpix2 = vec_unaligned_load(pix2);
         pix2 += 8;
-        //unpack
+        // unpack
         vpix1h = vec_unpackh(vpix1);
         vdiff  = vec_sub(vpix1h, vpix2);
         vpix1l = vec_unpackl(vpix1);