ASEM-51 is a macro assembler for the Intel MCS-51 family of microcontrollers.
It is running on the PC under MS-DOS, Windows and Linux.
The ASEM-51 assembly language is based on the standard Intel syntax, and implements conditional assembly, macros, and include file processing. The assembler can output object code in Intel-HEX or Intel OMF-51 format as well as a detailed list file. The ASEM-51 package includes support for more than 180 8051 derivatives, a bootstrap program for MCS-51 target boards, and documentation in ASCII and HTML format.
[Freeware]
8051 Macro Assembler ASEM-51