c++ - 为什么linux中.text 虚拟内存段不是从0起始的？

From the Linkers and loaders book:

On 386 systems, the text base address is 0x08048000, which permits a reasonably large stack below the text while still staying above address 0x08000000, permitting most programs to use a single second-level page table. (Recall that on the 386, each second-level table maps 0x00400000 addresses.)

据我所知，这个数字没什么特殊含义，这个数值就是大佬们拍脑袋定的。
文档里说：虚拟内存不从0开始是为了可以预留一个足够大的read only堆，每个程序都可以在这里建立单独的2级页表。一个2级页表是0x00400000