http://webster.cs.ucr.edu/ har en masse guf omkring assembler. Jeg ved dog ikke med compilers men måske er Nasm blevet ported til 8051'eren...
Ellers kan du måske bruge denne side: http://www.crossware.com/datasheets/a8051nt.htm?chip=all
Jeg tvivler nu på at nasm er blevet "ported" til 8051'eren... og det er nok heller ikke det du "mener", men her er svaret i hvert fald, pøllehat!
"1.1 What Is NASM?
The Netwide Assembler, NASM, is an 80x86 assembler designed for portability and modularity. It supports a range of object file formats, including Linux and NetBSD/FreeBSD a.out, ELF, COFF, Microsoft 16-bit OBJ and Win32. It will also output plain binary files. Its syntax is designed to be simple and easy to understand, similar to Intel's but less complex. It supports Pentium, P6, MMX, 3DNow!, SSE and SSE2 opcodes, and has macro capability"