Crossassembler

Crossassembler is a software tool that translates assembly language source code into machine code for a target processor while running on a host system that may be different from the target. It is a key component of cross-development workflows, enabling software creation for systems that are not directly executable on the host machine, such as embedded devices, retro computers, or game consoles. A crossassembler reads source containing labels, constants, macros, and directives, and outputs binary or object data suitable for linking or loading by an emulator or hardware bootloader.

Typical features include support for multiple target CPUs and instruction sets, macro facilities, local labels, conditional assembly, include files, and relocation. It often provides various output formats (raw binaries, hexadecimal dumps, or object modules) and listing files for debugging. Many tools also include syntax compatibility options to help port existing code between architectures.

Usage involves integrating the crossassembler into build scripts, often alongside a linker and an emulator or hardware interface. Source code can be organized into modules and assembled separately, with the linker combining them into a final image. The produced output is typically used for loading into emulators for testing or writing to ROMs or flash for actual hardware.

Historically, crossassemblers emerged with the rise of cross-development in the 1980s and remain important in retro computing, game console development, and modern embedded projects. See also assemblers, cross-compilers, and retrocomputing development environments.