You are connected to the intro-computer. This is a processor, from which the heart is laid open and made visible during the run. In executing your program it is possible to follow the flow of data between memory and registers. The computer always works in one of the following states : 1.: console mode 2.: run or execute mode In console mode, it is possible to load the computer memory with your program and data. When the loading process is ready, you can execute your program. It is possible to make changes in the way your program will be executed. The main memory of consists of 157 words. Only 21 words are shown during the execution of your program. You can say where to start with these 21 visible words. it is also possible to choose how the execution of your program can be delayed. Thereby is N: no delay, A: delay with a number of stops of 20 msec, and U: the computer will halt until you have understood what was happening. Then you can push the space-bar and the next action will take place. This is possible between the instructions and between the micro-steps. Memory organisation: 12 bit words. 1XXX = ADD 6XXX = STRI 2XXX = ISZ 7001 = IAC 7440 = SIZ Instruction-set of computer : >>> 3XXX = STR 7040 = CMA 7500 = SIM 4XXX = ADDI 7200 = CLA 7510 = SIP 5XXX = JMP 7402 = HLT

Also is the documentation and description of the 'intro computer'. a program originally writte by Mr. Jan Posthuma and translated into English by Mr. Dick Biesboer, both workng for the Education department of DEC Utrecht, the Netherlands.

There are 2 versions of the program.

• cpu52.mac is the original one which has been re-typed from a paper listing and uses the VT52 mode of a VT-100.
• cpu101.mac is my version, which ahs been adapted to make use of the native VT-100 mode, as well as some changed graphics, flow lines and re-organised code.

When using SIMH, use an xterm to conect to it. for a VT52 emulation, use 'xterm -ti vt52 -tn vt52' for a vt100 emulation, use 'xterm -ti vt100 -tn vt100'