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swab函数 (#53)
* swab函数 Signed-off-by: Yuqia <15287042733@163.com> * 修正格式 Signed-off-by: Yuqia <15287042733@163.com> Co-authored-by: fslongjin <longjin@RinGoTek.cn>
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@ -26,3 +26,11 @@ pid_t fork(void);
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* @return pid_t
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*/
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pid_t vfork(void);
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/**
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* @brief 交换n字节
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* @param src 源地址
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* @param dest 目的地址
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* @param nbytes 交换字节数
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*/
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void swab(void *restrict src, void *restrict dest, ssize_t nbytes);
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@ -1,4 +1,5 @@
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#include <common/unistd.h>
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#include <common/glib.h>
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/**
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* @brief fork当前进程
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@ -19,3 +20,20 @@ pid_t vfork(void)
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{
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return (pid_t)enter_syscall_int(SYS_VFORK, 0, 0, 0, 0, 0, 0, 0, 0);
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}
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void swab(void *restrict src, void *restrict dest, ssize_t nbytes)
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{
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unsigned char buf[32];
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char *_src = src;
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char *_dest = dest;
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uint32_t transfer;
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for (; nbytes > 0; nbytes -= transfer)
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{
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transfer = (nbytes > 32) ? 32 : nbytes;
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memcpy(buf, _src, transfer);
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memcpy(_src, _dest, transfer);
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memcpy(_dest, buf, transfer);
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_src += transfer;
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_dest += transfer;
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}
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}
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@ -48,4 +48,32 @@ char* strcpy(char* dst, const char* src);
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*/
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char *strcat(char *dest, const char *src);
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#define memcpy(dst, src, n) __builtin_memcpy(dst, src, n)
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/**
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* @brief 内存拷贝函数
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*
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* @param dst 目标数组
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* @param src 源数组
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* @param Num 字节数
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* @return void*
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*/
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static void *memcpy(void *dst, const void *src, long Num)
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{
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int d0 = 0, d1 = 0, d2 = 0;
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__asm__ __volatile__("cld \n\t"
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"rep \n\t"
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"movsq \n\t"
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"testb $4,%b4 \n\t"
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"je 1f \n\t"
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"movsl \n\t"
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"1:\ttestb $2,%b4 \n\t"
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"je 2f \n\t"
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"movsw \n\t"
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"2:\ttestb $1,%b4 \n\t"
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"je 3f \n\t"
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"movsb \n\t"
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"3: \n\t"
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: "=&c"(d0), "=&D"(d1), "=&S"(d2)
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: "0"(Num / 8), "q"(Num), "1"(dst), "2"(src)
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: "memory");
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return dst;
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}
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@ -3,6 +3,7 @@
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#include <libc/errno.h>
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#include <libc/stdio.h>
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#include <libc/stddef.h>
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#include <libc/string.h>
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/**
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* @brief 关闭文件接口
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@ -158,3 +159,26 @@ int rmdir(const char *path)
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{
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return syscall_invoke(SYS_RMDIR, (uint64_t)path, 0, 0, 0, 0, 0, 0, 0);
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}
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/**
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* @brief 交换n字节
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* @param src 源地址
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* @param dest 目的地址
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* @param nbytes 交换字节数
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*/
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void swab(void *restrict src, void *restrict dest, ssize_t nbytes)
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{
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unsigned char buf[32];
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char *_src = src;
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char *_dest = dest;
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uint32_t transfer;
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for (; nbytes > 0; nbytes -= transfer)
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{
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transfer = (nbytes > 32) ? 32 : nbytes;
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memcpy(buf, _src, transfer);
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memcpy(_src, _dest, transfer);
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memcpy(_dest, buf, transfer);
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_src += transfer;
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_dest += transfer;
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}
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}
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@ -88,7 +88,7 @@ int64_t chdir(char *dest_path);
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* @param argv 参数列表
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* @return int
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*/
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int execv(const char* path, char * const argv[]);
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int execv(const char *path, char *const argv[]);
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/**
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* @brief 睡眠指定时间
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@ -104,4 +104,12 @@ extern int usleep(useconds_t usec);
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* @param path 绝对路径
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* @return int 错误码
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*/
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int rmdir(const char* path);
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int rmdir(const char *path);
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/**
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* @brief 交换n字节
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* @param src 源地址
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* @param dest 目的地址
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* @param nbytes 交换字节数
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*/
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void swab(void *restrict src, void *restrict dest, ssize_t nbytes);
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