about five times faster in the V80 than in the V60/V70. All floating-point operations are largely implemented in microcode across the processor family and are thus fairly slow. On the V60/V70, the 32-bit floating-point operations take 120/116/137 cycles for addition/multiplication/division, while the corresponding 64-bit floating-point operations take 178/270/590 cycles. The V80 has some limited hardware assist for phases of floating-point operations—e.g. decomposition into sign, exponent, and mantissa—thus its floating-point unit was claimed to be up to three times as effective as that of the V70, with 32-bit floating-point operations taking 36/44/74 cycles and 64-bit operations taking 75/110/533 cycles (addition/multiplication/division). Operating systems Unix (non-real-time and real-time) NEC ported several variants of the Unix operating system to its V60/V70/V80 processors for user-application-oriented systems, including real-time ones. The first flavor of NEC's UNIX System V port for V60 was called PC-UX/V Rel 2.0 (V60). (Also refer to external link photos below.) NEC developed a Unix variant with a focus on real-time operation to run on V60/V70/V80. Called Real-time UNIX RX-UX 832, it has a double-layered kernel structure, with all task scheduling handled by the real-time kernel. A multiprocessor version of RX-UX 832 was also developed, named MUSTARD (Multiprocessor Unix for Embedded Real-Time Systems). The MUSTARD-powered computer prototype uses eight V70 processors. It utilizes FRM function, and can configure and change the configuration of master and checker upon request. I-TRON (real-time) For hardware-control-oriented embedded systems, the I-TRON-based real-time operating system, named RX616, was implemented by NEC for the V60/V70. The 32-bit RX616 was a continuous fork from the 16-bit RX116, which was for the V20-V50. FlexOS (real-time) In 1987, Digital Research, Inc. also announced that they were planning on porting FlexOS to the V60 and V70. CP/M and DOS (legacy 16-bit) The V60 could also run CP/M and DOS programs (ported from the V20-V50 series) using V20/V30 emulation mode. According to a 1991 article in InfoWorld, Digital Research was working on a version of Concurrent DOS for the V60 at some point; but this was never released, as the V60/V70 processors were not imported to the US for use in PC clones. Development tools C/C++ cross-compilers As part of its development tool kit and integrated development environment (IDE), NEC had its own C-compiler, the PKG70616 "Software Generation tool package for V60/V70". In addition, GHS (Green Hills Software) made its native mode C compiler (MULTI), and MetaWare, Inc. (currently Synopsys, via ARC International) made one,