automatic room light controller with bidirectiona visitor counterl

in RIDE,there is a separate option for assembly code(for.a51).right?i think in original code the header file was given as include_reg51.pdf.now when I want to convert the code to keil by changing some syntax like DS to EQU with ram addresses,how should I include the header file?keil can be used to compile assembly code also?or we have to write in c only?

keil has both assembler as well as compiler, so you can easily assemble .a51, .asm files basically assembly files. you can use DS in keil also. read assembler guide.