在16-bit地址模式(BITS 16 而没有67,或者BITS32而带67),SIB byte不被使用。对于mod和r/m的通用规则(下面会给出,有一个例外)是: mod字段给出位移字段的长度(the length of the displacement field): 0 means no displacement, 1 means one byte, and 2 means two bytes. r/mfield encodes the combinati...
The CPU can simply issue a read for the 64-bit block that contains those 4 bytes. That means it either gets 4 extra bytes before the requested data, or after it. But in both cases, it only takes a single read. 32-bit alignment of 32-bit-wide data ensures that it won't cross a ...
除此之外,现代x86设计还包含一个SIMD单元(见下文的SSE),其中指令可以并行工作在(一个或两个)128位字上,每个字包含两个或四个浮点数(分别宽64位或32位),或者可选地,2、4、8或16个整数(分别宽64位、32位、16位或8位)。 The presence of wide SIMD registers means that existing x86 processors can load...
在操作系统中,允许程序使用逻辑地址来访问内存,而不是实际地址,所以这64TB内存是虚拟地址空间(要开启页功能,16章讲)(全局地址空间可以有32TB,一个任务的局部空间为32TB,也就是一个任务的总空间可以是64TB,但是操作系统允许程序的编写者使用虚拟地址(逻辑地址)来访问内存。同一块内存,可以让多任务,或者是每个任务...
bit value 32-bit value 64-bit value 2's complement Single-precision floating point Range -231 to 231-1 -32768 to 32767 -231 to 231-1 -263 to 263-1 true or false true or false true or false true or false true or false -128 to 127 10-37 to 1038 (1) Reference Guide for x86-...
The Intel x86 processor uses complex instruction set computer (CISC) architecture, which means there is a modest number of special-purpose registers instead of large quantities of general-purpose registers. It also means that complex special-purpose instructions will predominate....
1) 0x1(IL_ONLY) It means that assembly’s code is IL_ONLY that is it is pure IL thus it can be compiled to either 32 bit or 64 bit2) 0x2(32BIT_ONLY) means that assembly’s code must be compiled to 32 bit code and cannot be compiled to 64 bit....
基于2.6.32内核 一、现象 在x86_64的64位操作系统环境下,一个程序执行coredump,从coredump文件可以看到,导致coredump的问题是由于执行new操作时分配内存失败导致的。这个问题看起来让人有些莫名惊诧,用掉64bit下的所有虚拟地址空间,这是什么概念(这个惊诧可以用莱芜战役后国民党第二绥靖区司令长官王耀武的一句话来类比...
2) 0x2(32BIT_ONLY) means that assembly’s code must be compiled to 32 bit code and cannot be compiled to 64 bit. 3) 0x8 means assembly is signed. Open assembly file in ILDASM and have a look at its manifest. Value of corflags field can be found at bottom of the manifest file....
uses 256-bit vector registers, and splits 512-bit instructions into two micro-ops. That means ...