0x00400000

0x00400000 is a 32‑bit hexadecimal number that represents an address in a computer’s virtual or physical memory space. In many common operating systems and processor architectures this value is used as a fixed load address for executable code or core system components.

On the MIPS architecture, 0x00400000 is the standard base address at which user‑space programs are mapped into memory. In MIPS simulators and in operating systems such as Linux running on MIPS, the text (code) section of a program normally begins at this address. The convention originates from the MIPS‑32 unofficial “user mode” memory layout and has been inherited by many educational tools and kernel configurations.

In the ELF file format used by Linux on the x86‑64 platform, a statically linked executable typically has its first program header at virtual address 0x00400000. This aligns the binary with the operating system’s default memory mapping for user processes and ensures that code segments, data segments, and the stack are positioned in predictable locations. The same address is also employed by embedded systems that use a simplified ELF image format.

The choice of 0x00400000 is largely conventional rather than dictated by hardware. It provides a convenient boundary that is far enough above zero to avoid null‑pointer issues while leaving ample lower address space for hardware devices and system call tables. As a result, the value appears in a variety of system documentation, debuggers, and bootloaders, where it serves as a reference point for instruction fetches, memory protection, and symbol resolution.