an architecture that had single-byte registers Wild guess, but the OP might be talking about the Intel 8051. Single-byte registers, and depending on the C com

an architecture that had single-byte registers Wild guess, but the OP might be talking about the Intel 8051. Single-byte registers, and depending on the C compiler (and there are a few of them) 8-bit int* pointing to the first 128/256 bytes of memory, but up to 64K of (much slower) memory is supported in different memory spaces with different instructions and a 16-bit register called DPTR (and some implementations have 2 DPTR registers). C support for these additional spaces is mostly via compiler extensions analogous but different from the old 8086 NEAR and FAR pointers. I'm obviously greatly simplifying and leaving out a ton of details. Oh, yeah...on 8051 you need to support bit addressing as well, at least for the 16 bytes from 20h to 2Fh. It's an odd chip.