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/*
picoChip GCC support for 32-bit logical shift right.
Copyright (C) 2003, 2004, 2005, 2008, 2009 Free Software Foundation, Inc.
Contributed by Picochip 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;
}
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