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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgcc/] [config/] [picochip/] [ashlsi3.c] - Rev 741
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/* picoChip GCC support for 32-bit shift left. 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/>. */ #ifndef PICOCHIP #error "Intended for compilation for PICOCHIP only." #endif 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 __ashlsi3(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 == 0) return value.l; */ 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 lower `count' bits of the high word. Shift the upper `count' bits of the low word into the high word. This is only required when the count is non-zero. */ if (count != 0) { temp = 16 - count; temp = value.s.low >> temp; result.s.high |= temp; } } else { /* Shift the lower word of the source into the upper word of the result, and zero the result's lower word. */ count -= 16; result.s.high = value.s.low << count; result.s.low = 0; } return result.l; }
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