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commit 4fd78583f7fdcaf13820ab1a4b1908d0c4f3cfeb Author: lipengfei28 <[email protected]> AuthorDate: Tue Jun 18 20:00:04 2024 +0800 libc: add find_next_zero_bit The pci ep framework use bitmap manage free bar Signed-off-by: lipengfei28 <[email protected]> --- include/nuttx/bits.h | 8 +++ libs/libc/misc/CMakeLists.txt | 1 + libs/libc/misc/Make.defs | 2 +- libs/libc/misc/lib_bitmap.c | 116 ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 126 insertions(+), 1 deletion(-) diff --git a/include/nuttx/bits.h b/include/nuttx/bits.h index c39d75dff3..9b0e133b11 100644 --- a/include/nuttx/bits.h +++ b/include/nuttx/bits.h @@ -93,6 +93,9 @@ (*(((FAR unsigned long *)(addr)) + BIT_WORD(nr)) & \ BIT_WORD_MASK(nr)) +#define find_first_zero_bit(addr, size) \ + find_next_zero_bit((addr), (size), 0) + /**************************************************************************** * Type Definitions ****************************************************************************/ @@ -112,6 +115,11 @@ extern "C" /**************************************************************************** * Public Function Prototypes ****************************************************************************/ +#ifndef __ASSEMBLER__ +unsigned long find_next_zero_bit(FAR const unsigned long *addr, + unsigned long size, + unsigned long offset); +#endif #undef EXTERN #ifdef __cplusplus diff --git a/libs/libc/misc/CMakeLists.txt b/libs/libc/misc/CMakeLists.txt index 7ddb3f5979..61301e3d70 100644 --- a/libs/libc/misc/CMakeLists.txt +++ b/libs/libc/misc/CMakeLists.txt @@ -24,6 +24,7 @@ list( APPEND SRCS + lib_bitmap.c lib_mknod.c lib_umask.c lib_utsname.c diff --git a/libs/libc/misc/Make.defs b/libs/libc/misc/Make.defs index c6d4c107a8..281c662f00 100644 --- a/libs/libc/misc/Make.defs +++ b/libs/libc/misc/Make.defs @@ -20,7 +20,7 @@ # Add the internal C files to the build -CSRCS += lib_mknod.c lib_umask.c lib_utsname.c lib_getrandom.c +CSRCS += lib_bitmap.c lib_mknod.c lib_umask.c lib_utsname.c lib_getrandom.c CSRCS += lib_xorshift128.c lib_tea_encrypt.c lib_tea_decrypt.c CSRCS += lib_cxx_initialize.c lib_impure.c lib_memfd.c lib_mutex.c CSRCS += lib_fchmodat.c lib_fstatat.c lib_getfullpath.c lib_openat.c diff --git a/libs/libc/misc/lib_bitmap.c b/libs/libc/misc/lib_bitmap.c new file mode 100644 index 0000000000..276320b2a3 --- /dev/null +++ b/libs/libc/misc/lib_bitmap.c @@ -0,0 +1,116 @@ +/**************************************************************************** + * libs/libc/misc/lib_bitmap.c + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you 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. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <assert.h> +#include <errno.h> +#include <debug.h> +#include <string.h> + +#include <nuttx/bits.h> + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: find_next_zero_bit + * + * Description: + * This function is used to find the first cleared bit in a memory region. + * + * Invoke to get the bit set in map, implement find_{first,next}_zero_bit. + * + * Input Parameters: + * addr - Map start memory address + * size - Max size to find bit + * offset - Offset of start to finding + * + * Returned Value: + * Return index position（0 ~ size-1）if Finded, otherwise return size + ****************************************************************************/ + +unsigned long find_next_zero_bit(FAR const unsigned long *addr, + unsigned long size, + unsigned long offset) +{ + FAR const unsigned long *p = addr + BIT_WORD(offset); + unsigned long result = offset & ~(BITS_PER_LONG - 1); + unsigned long tmp; + + if (offset >= size) + { + return size; + } + + size -= result; + offset %= BITS_PER_LONG; + if (offset) + { + tmp = *(p++); + tmp |= ~0ul >> (BITS_PER_LONG - offset); + if (size < BITS_PER_LONG) + { + goto found_first; + } + + if (~tmp) + { + goto found_middle; + } + + size -= BITS_PER_LONG; + result += BITS_PER_LONG; + } + + while (size & ~(BITS_PER_LONG - 1)) + { + if (~(tmp = *(p++))) + { + goto found_middle; + } + + result += BITS_PER_LONG; + size -= BITS_PER_LONG; + } + + if (!size) + { + return result; + } + + tmp = *p; + +found_first: + tmp |= ~0ul << size; + + /* Are any bits zero? */ + + if (tmp == ~0ul) + { + return result + size; + } + +found_middle: + return result + ffsl(~tmp) - 1; +}
