I370 - a new dimension of microprogramming

Abstract

The internal 370 mode (I370) is a high level microprogramming interface. It significantly improves microcode development productivity and portability.I370 is a subset of the S/370 architecture and has special functions for access to non-S/370 system resources. It facilitates the utilization of existing high-level languages for microprogramming.In general, I370 can be supported by any S/370 CPU, independent of its internal design and implementation. It is used in the IBM 9377 Model 90 system to implement major parts of S/370 microcode.