| /* |
| * Copyright (c) 2014 Wind River Systems, Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /** |
| * @file |
| * @brief ARCv2 public nanokernel find-first-set interface |
| * |
| * ARC-specific nanokernel ffs interface. Included by ARC/arch.h. |
| */ |
| |
| #ifndef _ARCH_ARC_V2_FFS_H_ |
| #define _ARCH_ARC_V2_FFS_H_ |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| #ifndef _ASMLANGUAGE |
| |
| #include <stdint.h> |
| |
| /** |
| * |
| * @brief find most significant bit set in a 32-bit word |
| * |
| * This routine finds the first bit set starting from the most significant bit |
| * in the argument passed in and returns the index of that bit. Bits are |
| * numbered starting at 1 from the least significant bit. A return value of |
| * zero indicates that the value passed is zero. |
| * |
| * @return most significant bit set, 0 if @a op is 0 |
| */ |
| |
| #if defined(__GNUC__) |
| static ALWAYS_INLINE unsigned int find_msb_set(uint32_t op) |
| { |
| unsigned int bit; |
| |
| __asm__ volatile( |
| |
| /* see explanation in ffs.S */ |
| "fls.f %0, %1;\n\t" |
| "add.nz %0, %0, 1;\n\t" |
| : "=r"(bit) |
| : "r"(op)); |
| |
| return bit; |
| } |
| #endif |
| |
| /** |
| * |
| * @brief find least significant bit set in a 32-bit word |
| * |
| * This routine finds the first bit set starting from the least significant bit |
| * in the argument passed in and returns the index of that bit. Bits are |
| * numbered starting at 1 from the least significant bit. A return value of |
| * zero indicates that the value passed is zero. |
| * |
| * @return least significant bit set, 0 if @a op is 0 |
| */ |
| |
| #if defined(__GNUC__) |
| static ALWAYS_INLINE unsigned int find_lsb_set(uint32_t op) |
| { |
| unsigned int bit; |
| |
| __asm__ volatile( |
| |
| /* see explanation in ffs.S */ |
| "ffs.f %0, %1;\n\t" |
| "add.nz %0, %0, 1;\n\t" |
| "mov.z %0, 0;\n\t" |
| : "=&r"(bit) |
| : "r"(op)); |
| |
| return bit; |
| } |
| #endif |
| |
| #endif /* _ASMLANGUAGE */ |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* _ARCH_ARC_V2_FFS_H_ */ |