Imported gcc-4.4.3

[msp430-gcc.git] / gcc / config / spu / mfc_multi_tag_reserve.c

diff --git a/gcc/config/spu/mfc_multi_tag_reserve.c b/gcc/config/spu/mfc_multi_tag_reserve.c
new file mode 100644 (file)
index 0000000..06d7025
--- /dev/null
+++ b/gcc/config/spu/mfc_multi_tag_reserve.c
@@ -0,0 +1,84 @@
+/* Copyright (C) 2007, 2009 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+#include <spu_mfcio.h>
+extern vector unsigned int __mfc_tag_table;
+
+/* Reserve a sequential group of tags for exclusive use.  The number of
+   tags to be reserved is specified by the <number_of_tags> parameter.
+   This routine returns the first tag ID for a sequential list of
+   available tags and marks them as reserved. The reserved group
+   of tags is in the range starting from the returned tag through
+   the returned tag + <number_of_tags>-1.
+
+   If the number of tags requested exceeds the number of available
+   sequential tags, then MFC_DMA_TAG_INVALID is returned indicating
+   that the request could not be serviced.  */
+
+unsigned int
+__mfc_multi_tag_reserve (unsigned int number_of_tags)
+{
+  vector unsigned int table_copy;
+  vector unsigned int one = (vector unsigned int)
+        { 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
+  vector unsigned int count_busy, is_valid;
+  vector unsigned int count_total;
+  vector unsigned int count_avail = (vector unsigned int) { 0, 0, 0, 0 };
+  vector unsigned int index = (vector unsigned int) { 0, 0, 0, 0 };
+
+  table_copy = __mfc_tag_table;
+
+
+  /* count_busy: number of consecutive busy tags
+     count_avail: number of consecutive free tags
+     table_copy: temporary copy of the tag table
+     count_total: sum of count_busy and count_avail
+     index: index of the current working tag  */
+  do
+    {
+      table_copy = spu_sl (table_copy, count_avail);
+
+      count_busy = spu_cntlz (table_copy);
+      table_copy = spu_sl (table_copy, count_busy);
+      count_avail = spu_cntlz (spu_xor(table_copy, -1));
+      count_total = spu_add (count_busy, count_avail);
+      index = spu_add (index, count_total);
+    }
+  while (spu_extract (count_avail, 0) < number_of_tags
+        && spu_extract (table_copy, 0) != 0);
+
+  index = spu_sub (index, count_avail);
+
+  /* is_valid is set to 0xFFFFFFFF if table_copy == 0, 0 otherwise.  */
+  is_valid = spu_cmpeq (table_copy, 0);
+  index = spu_sel (index, is_valid, is_valid);
+
+  /* Now I need to actually mark the tags as used.  */
+  table_copy = spu_sl (one, number_of_tags);
+  table_copy = spu_rl (table_copy, -number_of_tags - spu_extract (index, 0));
+  table_copy = spu_sel (table_copy, __mfc_tag_table, table_copy);
+  __mfc_tag_table = spu_sel (table_copy, __mfc_tag_table, is_valid);
+
+  return spu_extract (index, 0);
+}
+