The Capricorn family of microprocessors was developed by Hewlett-Packard in the late 1970s for the HP Series 80 scientific microcomputers.
Each low-level instruction modifies data beginning at the register addressed up to the next boundary.
Variable-length instructions let the programmer treat data in the upper 32 registers as entities between one and eight bytes in length — for example, two eight-byte values (e.g. mantissa of a floating-point number) can be added using a single instruction.
For direct memory access, the CPU can be halted by an external device.
The Capricorn CPU was implemented as a silicon-gate NMOS logic circuit (4.93×4.01 mm) in a 28-pin dual in-line package, with an 8-bit, multiplexed external bus.