问题
MOV is probably the first instruction everyone learns while learning ASM.
Just now I encountered a book Assembly Language Programming in GNU/Linux for IA32 Architectures By Rajat Moona which says:
alt text http://i.imagehost.org/0897/mov.gif
But I learnt that it is MOV dest, src. Its like "Load dest with src". Even Wiki says the same.
I'm not saying that the author is wrong. I know that he is right. But what am I missing here?
btw.. he is using GCC's as to assemble these instructions. But that shouldn't change the instruction syntax right?
回答1:
mov dest, src is called Intel syntax.
mov src, dest is called AT&T syntax.
UNIX assemblers including the GNU assembler uses AT&T syntax, all other x86 assemblers I know of uses Intel syntax. You can read up on the differences on wikipedia.
回答2:
Yes, as/gas use AT&T syntax that uses the order src,dest. MASM, TASM, NASM, etc. all use the order 'dest, src". As it happens, AT&T syntax doesn't fit very well with Intel processors, and (at least IMO) is a nearly unreadable mess. E.g. movzx comes out particularly bad.
回答3:
There are two distinct types of assembly language syntax - Intel and AT&T syntax. You can find a comparison of both on Wikipedia's assembly language page.
Chances are your book uses the AT&T syntax, where the source operand comes before the destination.
来源：https://stackoverflow.com/questions/2397528/mov-src-dest-or-mov-dest-src