I had to program the 8048 a lot of years ago and certainly I prefer to forget that work. In particular I remember one limitation: Conditional jumps were limited to a 256 ABSOLUTE page. I had to assemble many times to eliminate the "out of page errors" but new errors appeared again. And it tooks about 20 minutes to assemble 1 K of code with an Intel´s development tool!. I think that the 8049 is similar to the 8048, but you can find more details in an Intel's old handbook. Both are ancestors (or is predecessors the right word in English?, sorry...) of the 8051 family.