什么是之间和QUOT的差异; CLD"和"性病QUOT;在汇编语言指令?
好了,我知道,CLD清方向标志和STD设置方向标志。
但什么是在设置和清除方向标志意义呢?
well, I know that CLD clears direction flag and STD sets direction flag. but what's the point in setting and clearing direction flag?
该方向标志被用来影响其中的 REP
使用时,一些指令工作的方向> preFIX。还有一些由这个标志直接影响指令,例如 MOVS
, LODS
,中汽南方
,和许多其他。
The direction flag is used to influence the direction in which some of the instructions work when used with the REP
prefix. There is a number of instructions that are influenced by this flag directly, for example MOVS
, LODS
, SCAS
, and many others.
在简单地说,当方向标志为0,说明通过增加数据指针每次迭代后(直到 ECX
工作为零或其他一些条件,视 REP
preFIX),而如果该标志为1时,指针减
In a nutshell, when the direction flag is 0, the instructions work by incrementing the pointer to the data after every iteration (until ECX
is zero or some other condition, depending on the flavour of the REP
prefix), while if the flag is 1, the pointer is decremented.