Imported gcc-4.4.3

[msp430-gcc.git] / gcc / config / picochip / libgccExtras / lshrsi3.c

diff --git a/gcc/config/picochip/libgccExtras/lshrsi3.c b/gcc/config/picochip/libgccExtras/lshrsi3.c
new file mode 100644 (file)
index 0000000..5686b20
--- /dev/null
+++ b/gcc/config/picochip/libgccExtras/lshrsi3.c
@@ -0,0 +1,76 @@
+/*
+
+picoChip GCC support for 32-bit logical shift right.
+
+Copyright (C) 2003, 2004, 2005, 2008, 2009  Free Software Foundation, Inc.
+Contributed by picoChip Designs Ltd.
+Maintained by Daniel Towner (daniel.towner@picochip.com)
+
+This file 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.
+
+This file 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/>.  */
+
+typedef int HItype __attribute__ ((mode (HI)));
+typedef unsigned int UHItype __attribute__ ((mode (HI)));
+typedef unsigned int USItype __attribute__ ((mode (SI)));
+
+typedef struct USIstruct {
+  UHItype low, high;
+} USIstruct;
+
+typedef union USIunion {
+  USItype l;
+  USIstruct s;
+} USIunion;
+
+USItype __lshrsi3(USIunion value, HItype count) {
+  USIunion result;
+  int temp;
+
+  /* Ignore a zero count until we get into the (count < 16)
+     clause. This is slightly slower when shifting by zero, but faster
+     and smaller in all other cases (due to the better scheduling
+     opportunities available by putting the test near computational
+     instructions. */
+
+  if (count < 16) {
+    /* Shift low and high words by the count. */
+    result.s.low = value.s.low >> count;
+    result.s.high = value.s.high >> count;
+     
+    /* There is now a hole in the upper `count' bits of the low
+       word. Shift the lower `count' bits of the upper word into the
+       low word. This only works when count isn't zero. */
+    if (count != 0) {
+      temp = value.s.high << (16 - count);
+      result.s.low |= temp;
+    }
+
+  } else {
+    /* Shift the upper word of the source into the lower word of the
+       result, and zero the result's upper word. Note that we actually
+       ned to shift by (count - 16), but as we are only using the
+       bottom 4 bits, this is equivalent to shifting by count. */
+    result.s.low = value.s.high >> count;
+    result.s.high = 0;
+
+  }
+
+  return result.l;
+
+}