平面内存模型与实地址模式内存模型

Question

来自英特尔 IA32 软件开发人员手册，

Flat memory model — Memory appears to a program as a single, continuous address  
space. This space is called a linear address space. Code, data, and stacks are  
all contained in this address space. Linear address space is byte addressable,  
with addresses running contiguously from 0 to 2^32 - 1 (if not in 64-bit mode).  
An address for any byte in linear address space is called a linear address.

Real-address mode memory model — This is the memory model for the Intel 8086  
processor. It is supported to provide compatibility with existing programs  
written to run on the Intel 8086 processor. The realaddress mode uses a specific  
implementation of segmented memory in which the linear address space for the  
program and the operating system/executive consists of an array of segments of up  
to 64 KBytes in size each. The maximum size of the linear address space in  
real-address mode is 220 bytes.

根据上面的信息，这两种内存模型的区别仅仅是可寻址的内存空间大小吗？

Answer 1

实地址模式也使用段。

平面内存模型是大多数处理器（不是来自英特尔）使用的直观、直接的内存模型。大多数处理器不支持多种内存模型。英特尔支持这一点以及许多其他兼容性。

实地址模式使用段寄存器。地址是程序员指定的值加上段寄存器中的值，在某些情况下，段可能是特定指令隐含的。