Add optimized memcpy implementation for sh4 (from Stuart Menefy @STMicroelectronics).

This implementation is based on 'backward copying'.

Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>

4 files changed, 201 insertions, 190 deletions

diff --git a/libc/string/generic/_memcpy_fwd.c b/libc/string/generic/_memcpy_fwd.c
new file mode 100644
index 000000000..470165a57
--- /dev/null
+++ b/libc/string/generic/_memcpy_fwd.c
@@ -0,0 +1,185 @@
+/* _wordcopy_fwd_aligned -- Copy block beginning at SRCP to
+   block beginning at DSTP with LEN `op_t' words (not LEN bytes!).
+   Both SRCP and DSTP should be aligned for memory operations on `op_t's.  */
+
+static void _wordcopy_fwd_aligned (long int dstp, long int srcp, size_t len)
+{
+  op_t a0, a1;
+
+  switch (len % 8)
+    {
+    case 2:
+      a0 = ((op_t *) srcp)[0];
+      srcp -= 6 * OPSIZ;
+      dstp -= 7 * OPSIZ;
+      len += 6;
+      goto do1;
+    case 3:
+      a1 = ((op_t *) srcp)[0];
+      srcp -= 5 * OPSIZ;
+      dstp -= 6 * OPSIZ;
+      len += 5;
+      goto do2;
+    case 4:
+      a0 = ((op_t *) srcp)[0];
+      srcp -= 4 * OPSIZ;
+      dstp -= 5 * OPSIZ;
+      len += 4;
+      goto do3;
+    case 5:
+      a1 = ((op_t *) srcp)[0];
+      srcp -= 3 * OPSIZ;
+      dstp -= 4 * OPSIZ;
+      len += 3;
+      goto do4;
+    case 6:
+      a0 = ((op_t *) srcp)[0];
+      srcp -= 2 * OPSIZ;
+      dstp -= 3 * OPSIZ;
+      len += 2;
+      goto do5;
+    case 7:
+      a1 = ((op_t *) srcp)[0];
+      srcp -= 1 * OPSIZ;
+      dstp -= 2 * OPSIZ;
+      len += 1;
+      goto do6;
+
+    case 0:
+      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
+	return;
+      a0 = ((op_t *) srcp)[0];
+      srcp -= 0 * OPSIZ;
+      dstp -= 1 * OPSIZ;
+      goto do7;
+    case 1:
+      a1 = ((op_t *) srcp)[0];
+      srcp -=-1 * OPSIZ;
+      dstp -= 0 * OPSIZ;
+      len -= 1;
+      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
+	goto do0;
+      goto do8;			/* No-op.  */
+    }
+
+  do
+    {
+    do8:
+      a0 = ((op_t *) srcp)[0];
+      ((op_t *) dstp)[0] = a1;
+    do7:
+      a1 = ((op_t *) srcp)[1];
+      ((op_t *) dstp)[1] = a0;
+    do6:
+      a0 = ((op_t *) srcp)[2];
+      ((op_t *) dstp)[2] = a1;
+    do5:
+      a1 = ((op_t *) srcp)[3];
+      ((op_t *) dstp)[3] = a0;
+    do4:
+      a0 = ((op_t *) srcp)[4];
+      ((op_t *) dstp)[4] = a1;
+    do3:
+      a1 = ((op_t *) srcp)[5];
+      ((op_t *) dstp)[5] = a0;
+    do2:
+      a0 = ((op_t *) srcp)[6];
+      ((op_t *) dstp)[6] = a1;
+    do1:
+      a1 = ((op_t *) srcp)[7];
+      ((op_t *) dstp)[7] = a0;
+
+      srcp += 8 * OPSIZ;
+      dstp += 8 * OPSIZ;
+      len -= 8;
+    }
+  while (len != 0);
+
+  /* This is the right position for do0.  Please don't move
+     it into the loop.  */
+ do0:
+  ((op_t *) dstp)[0] = a1;
+}
+
+/* _wordcopy_fwd_dest_aligned -- Copy block beginning at SRCP to
+   block beginning at DSTP with LEN `op_t' words (not LEN bytes!).
+   DSTP should be aligned for memory operations on `op_t's, but SRCP must
+   *not* be aligned.  */
+
+static void _wordcopy_fwd_dest_aligned (long int dstp, long int srcp, size_t len)
+{
+  op_t a0, a1, a2, a3;
+  int sh_1, sh_2;
+
+  /* Calculate how to shift a word read at the memory operation
+     aligned srcp to make it aligned for copy.  */
+
+  sh_1 = 8 * (srcp % OPSIZ);
+  sh_2 = 8 * OPSIZ - sh_1;
+
+  /* Make SRCP aligned by rounding it down to the beginning of the `op_t'
+     it points in the middle of.  */
+  srcp &= -OPSIZ;
+
+  switch (len % 4)
+    {
+    case 2:
+      a1 = ((op_t *) srcp)[0];
+      a2 = ((op_t *) srcp)[1];
+      srcp -= 1 * OPSIZ;
+      dstp -= 3 * OPSIZ;
+      len += 2;
+      goto do1;
+    case 3:
+      a0 = ((op_t *) srcp)[0];
+      a1 = ((op_t *) srcp)[1];
+      srcp -= 0 * OPSIZ;
+      dstp -= 2 * OPSIZ;
+      len += 1;
+      goto do2;
+    case 0:
+      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
+	return;
+      a3 = ((op_t *) srcp)[0];
+      a0 = ((op_t *) srcp)[1];
+      srcp -=-1 * OPSIZ;
+      dstp -= 1 * OPSIZ;
+      len += 0;
+      goto do3;
+    case 1:
+      a2 = ((op_t *) srcp)[0];
+      a3 = ((op_t *) srcp)[1];
+      srcp -=-2 * OPSIZ;
+      dstp -= 0 * OPSIZ;
+      len -= 1;
+      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
+	goto do0;
+      goto do4;			/* No-op.  */
+    }
+
+  do
+    {
+    do4:
+      a0 = ((op_t *) srcp)[0];
+      ((op_t *) dstp)[0] = MERGE (a2, sh_1, a3, sh_2);
+    do3:
+      a1 = ((op_t *) srcp)[1];
+      ((op_t *) dstp)[1] = MERGE (a3, sh_1, a0, sh_2);
+    do2:
+      a2 = ((op_t *) srcp)[2];
+      ((op_t *) dstp)[2] = MERGE (a0, sh_1, a1, sh_2);
+    do1:
+      a3 = ((op_t *) srcp)[3];
+      ((op_t *) dstp)[3] = MERGE (a1, sh_1, a2, sh_2);
+
+      srcp += 4 * OPSIZ;
+      dstp += 4 * OPSIZ;
+      len -= 4;
+    }
+  while (len != 0);
+
+  /* This is the right position for do0.  Please don't move
+     it into the loop.  */
+ do0:
+  ((op_t *) dstp)[0] = MERGE (a2, sh_1, a3, sh_2);
+}
diff --git a/libc/string/generic/memcopy.h b/libc/string/generic/memcopy.h
index df1ba9a97..fab4da764 100644
--- a/libc/string/generic/memcopy.h
+++ b/libc/string/generic/memcopy.h
@@ -107,6 +107,7 @@ typedef unsigned char byte;
 	}								      \
     } while (0)
 
+#ifdef __ARCH_HAS_BWD_MEMCPY__
 /* Copy *up to* NBYTES bytes from SRC_BP to DST_BP, with
    the assumption that DST_BP is aligned on an OPSIZ multiple.  If
    not all bytes could be easily copied, store remaining number of bytes
@@ -125,6 +126,8 @@ typedef unsigned char byte;
       (nbytes_left) = (nbytes) % OPSIZ;					      \
     } while (0)
 
+#endif
+
 /* Copy *up to* NBYTES_TO_COPY bytes from SRC_END_PTR to DST_END_PTR,
    beginning at the words (of type op_t) right before the pointers and
    continuing towards smaller addresses.  May take advantage of that
diff --git a/libc/string/generic/memcpy.c b/libc/string/generic/memcpy.c
index fa6606ceb..4284f2fe5 100644
--- a/libc/string/generic/memcpy.c
+++ b/libc/string/generic/memcpy.c
@@ -25,192 +25,6 @@
 
 /* Experimentally off - libc_hidden_proto(memcpy) */
 
-/* _wordcopy_fwd_aligned -- Copy block beginning at SRCP to
-   block beginning at DSTP with LEN `op_t' words (not LEN bytes!).
-   Both SRCP and DSTP should be aligned for memory operations on `op_t's.  */
-
-static void _wordcopy_fwd_aligned (long int dstp, long int srcp, size_t len)
-{
-  op_t a0, a1;
-
-  switch (len % 8)
-    {
-    case 2:
-      a0 = ((op_t *) srcp)[0];
-      srcp -= 6 * OPSIZ;
-      dstp -= 7 * OPSIZ;
-      len += 6;
-      goto do1;
-    case 3:
-      a1 = ((op_t *) srcp)[0];
-      srcp -= 5 * OPSIZ;
-      dstp -= 6 * OPSIZ;
-      len += 5;
-      goto do2;
-    case 4:
-      a0 = ((op_t *) srcp)[0];
-      srcp -= 4 * OPSIZ;
-      dstp -= 5 * OPSIZ;
-      len += 4;
-      goto do3;
-    case 5:
-      a1 = ((op_t *) srcp)[0];
-      srcp -= 3 * OPSIZ;
-      dstp -= 4 * OPSIZ;
-      len += 3;
-      goto do4;
-    case 6:
-      a0 = ((op_t *) srcp)[0];
-      srcp -= 2 * OPSIZ;
-      dstp -= 3 * OPSIZ;
-      len += 2;
-      goto do5;
-    case 7:
-      a1 = ((op_t *) srcp)[0];
-      srcp -= 1 * OPSIZ;
-      dstp -= 2 * OPSIZ;
-      len += 1;
-      goto do6;
-
-    case 0:
-      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
-	return;
-      a0 = ((op_t *) srcp)[0];
-      srcp -= 0 * OPSIZ;
-      dstp -= 1 * OPSIZ;
-      goto do7;
-    case 1:
-      a1 = ((op_t *) srcp)[0];
-      srcp -=-1 * OPSIZ;
-      dstp -= 0 * OPSIZ;
-      len -= 1;
-      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
-	goto do0;
-      goto do8;			/* No-op.  */
-    }
-
-  do
-    {
-    do8:
-      a0 = ((op_t *) srcp)[0];
-      ((op_t *) dstp)[0] = a1;
-    do7:
-      a1 = ((op_t *) srcp)[1];
-      ((op_t *) dstp)[1] = a0;
-    do6:
-      a0 = ((op_t *) srcp)[2];
-      ((op_t *) dstp)[2] = a1;
-    do5:
-      a1 = ((op_t *) srcp)[3];
-      ((op_t *) dstp)[3] = a0;
-    do4:
-      a0 = ((op_t *) srcp)[4];
-      ((op_t *) dstp)[4] = a1;
-    do3:
-      a1 = ((op_t *) srcp)[5];
-      ((op_t *) dstp)[5] = a0;
-    do2:
-      a0 = ((op_t *) srcp)[6];
-      ((op_t *) dstp)[6] = a1;
-    do1:
-      a1 = ((op_t *) srcp)[7];
-      ((op_t *) dstp)[7] = a0;
-
-      srcp += 8 * OPSIZ;
-      dstp += 8 * OPSIZ;
-      len -= 8;
-    }
-  while (len != 0);
-
-  /* This is the right position for do0.  Please don't move
-     it into the loop.  */
- do0:
-  ((op_t *) dstp)[0] = a1;
-}
-
-/* _wordcopy_fwd_dest_aligned -- Copy block beginning at SRCP to
-   block beginning at DSTP with LEN `op_t' words (not LEN bytes!).
-   DSTP should be aligned for memory operations on `op_t's, but SRCP must
-   *not* be aligned.  */
-
-static void _wordcopy_fwd_dest_aligned (long int dstp, long int srcp, size_t len)
-{
-  op_t a0, a1, a2, a3;
-  int sh_1, sh_2;
-
-  /* Calculate how to shift a word read at the memory operation
-     aligned srcp to make it aligned for copy.  */
-
-  sh_1 = 8 * (srcp % OPSIZ);
-  sh_2 = 8 * OPSIZ - sh_1;
-
-  /* Make SRCP aligned by rounding it down to the beginning of the `op_t'
-     it points in the middle of.  */
-  srcp &= -OPSIZ;
-
-  switch (len % 4)
-    {
-    case 2:
-      a1 = ((op_t *) srcp)[0];
-      a2 = ((op_t *) srcp)[1];
-      srcp -= 1 * OPSIZ;
-      dstp -= 3 * OPSIZ;
-      len += 2;
-      goto do1;
-    case 3:
-      a0 = ((op_t *) srcp)[0];
-      a1 = ((op_t *) srcp)[1];
-      srcp -= 0 * OPSIZ;
-      dstp -= 2 * OPSIZ;
-      len += 1;
-      goto do2;
-    case 0:
-      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
-	return;
-      a3 = ((op_t *) srcp)[0];
-      a0 = ((op_t *) srcp)[1];
-      srcp -=-1 * OPSIZ;
-      dstp -= 1 * OPSIZ;
-      len += 0;
-      goto do3;
-    case 1:
-      a2 = ((op_t *) srcp)[0];
-      a3 = ((op_t *) srcp)[1];
-      srcp -=-2 * OPSIZ;
-      dstp -= 0 * OPSIZ;
-      len -= 1;
-      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
-	goto do0;
-      goto do4;			/* No-op.  */
-    }
-
-  do
-    {
-    do4:
-      a0 = ((op_t *) srcp)[0];
-      ((op_t *) dstp)[0] = MERGE (a2, sh_1, a3, sh_2);
-    do3:
-      a1 = ((op_t *) srcp)[1];
-      ((op_t *) dstp)[1] = MERGE (a3, sh_1, a0, sh_2);
-    do2:
-      a2 = ((op_t *) srcp)[2];
-      ((op_t *) dstp)[2] = MERGE (a0, sh_1, a1, sh_2);
-    do1:
-      a3 = ((op_t *) srcp)[3];
-      ((op_t *) dstp)[3] = MERGE (a1, sh_1, a2, sh_2);
-
-      srcp += 4 * OPSIZ;
-      dstp += 4 * OPSIZ;
-      len -= 4;
-    }
-  while (len != 0);
-
-  /* This is the right position for do0.  Please don't move
-     it into the loop.  */
- do0:
-  ((op_t *) dstp)[0] = MERGE (a2, sh_1, a3, sh_2);
-}
-
 void *memcpy (void *dstpp, const void *srcpp, size_t len)
 {
   unsigned long int dstp = (long int) dstpp;
diff --git a/libc/string/generic/memmove.c b/libc/string/generic/memmove.c
index b2a017b16..7f945b150 100644
--- a/libc/string/generic/memmove.c
+++ b/libc/string/generic/memmove.c
@@ -24,12 +24,18 @@
 #include "memcopy.h"
 #include "pagecopy.h"
 
+#ifdef __ARCH_HAS_BWD_MEMCPY__
+/* generic-opt memmove assumes memcpy does forward copying! */
+#include "_memcpy_fwd.c"
+#endif
+
 /* Experimentally off - libc_hidden_proto(memmove) */
 /* Experimentally off - libc_hidden_proto(memcpy) */
 
 static void _wordcopy_bwd_aligned (long int dstp, long int srcp, size_t len)
 {
-  op_t a0, a1;
+  op_t a0 = 0;
+  op_t a1 = 0;
 
   switch (len % 8)
     {
@@ -133,7 +139,10 @@ static void _wordcopy_bwd_aligned (long int dstp, long int srcp, size_t len)
 
 static void _wordcopy_bwd_dest_aligned (long int dstp, long int srcp, size_t len)
 {
-  op_t a0, a1, a2, a3;
+  op_t a0 = 0;
+  op_t a1 = 0;
+  op_t a2 = 0;
+  op_t a3 = 0;
   int sh_1, sh_2;
 
   /* Calculate how to shift a word read at the memory operation
@@ -218,8 +227,8 @@ void *memmove (void *dest, const void *src, size_t len)
      Reduces the working set.  */
   if (dstp - srcp >= len)	/* *Unsigned* compare!  */
     {
-#if 1
-#warning REMINDER: generic-opt memmove assumes memcpy does forward copying!
+#ifndef __ARCH_HAS_BWD_MEMCPY__
+      /* Backward memcpy implementation cannot be used */
       memcpy(dest, src, len);
 #else
       /* Copy from the beginning to the end.  */