Hi Kishore,

I assume, you want not a listing, you want the monitor source code.

1.
monitors, like BIOS are dedicated to special hardware. so you should ask the hardware manufacturer.

2.
On most operating systems the basic I/O routines still written in assembler. This was the reason, that also no monitor in C exist.


3.
Simple by using a ISP / IAP / JTAG derivate you need no longer a monitor routine. Because such devices direct access and programmable over standard interfaces.
Eg. the Flip software over the UART to program the T89C51RD2 and many others.


Peter