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>

1 files changed, 185 insertions, 0 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);
+}