became common and the addressing system on the 2650 became a significant hindrance. The 2650 also contained an on-die call stack, rather than the more common solution that sets aside a location in memory to hold the stack. The stack pointer was held in three bits in PSW. An on-die stack is much faster, as the data can be accessed directly without waiting for it to be read from external memory, but it also takes up room on the die and is always limited in size as a result of practical tradeoffs. In the 2650, the stack was eight 15-bit entries deep, which is generally far too small to be used for high-level languages. While there were nine different addressing modes, the lack of 16-bit registers and the 13–15-bit address space prevented widespread use. Despite this, an operating system ("2650 DOS") was available, along with 8 KB and 12 KB BASIC interpreters (sold by Central Data Corporation USA), and many games of the Hunt the Wumpus style. Most programs were written in assembly language. Uses Signetics sold 2650-based microprocessor development boards, first the PC1001 and then its successor, the PC1500 "Adaptable Board Computer", ranging in price from A$165 to A$400. The chip by itself sold for around A$20. Several hardware construction projects and programming articles were published in magazines such as Electronics Australia and Elektor and related kits were sold by electronics stores. These factors led to its use by a number of hobbyists in many countries such as Australia, U.S.A., United Kingdom, the Netherlands and Germany. Two types of video game console used the Signetics 2650 or 2650A. The first group of consoles are based on the Signetics 2636 video display controller; the 1292 Advanced Programmable Video System and the closely related Interton Video Computer 4000 belong to this group. Those were released in Germany in 1976 and 1978 respectively. The second group of consoles were based on the Signetics 2637 as a video display controller; Emerson Arcadia 2001 which was released in 1982 and which used a Signetics 2650 running at 3.58 MHz as a CPU belong to this group together with many other ones software-compatible (Leonardo, Hanimex MPT-03 etc.). At least six coin-operated video games were released in the 1970s which used the 2650 CPU: Atari, Inc. Quiz Show, Meadows Games 3D Bowling, Meadows Games Gypsy Juggler, Meadows Games Lazer Command, Cinematronics Embargo, and a 1978 clone