GB1412783A - Computer system and method of programming same - Google Patents

Abstract

1412783 Programmable desk top calculator A GREBERT and F GERBSTADT 27 Oct 1972 [29 Oct 1971] 49591/72 Heading G4A The calculator has a keyboard unit 4, which inputs instructions in individual character machine language to text processor unit 8, and a display 6, e.g. an alphanumeric CRT display. The processor 8 (Fig. 2) has a stack/buffer/parameter control 10 (Fig. 3, not shown) which temporarily stores strings of symbols during machine language evaluation. An evaluate/call/ keyboard element 20 (Fig. 10, not shown) recognizes and directly analyses the machine language by partitioning the strings into individual instructions. Arithmetic/compare element 30 performs decimal arithmetic and comparison between two input character strings while substitution/literal element 40 allows transformation between predetermined parameter marks and strings which then represent the parameters. Unit 50 is for display, element 60 performs editing, while fetch/store element 70 controls a disc memory. The elements are joined by staticizing buses .110, 90, 100 and 82. Unit 10 has a read only microprogram unit and a random access memory partitioned into a buffer section and a stack section (Fig. 3, not shown). The read only unit holds the basic algorithms performed by unit 10 which are selected by a decoded instruction and used to either select one of the elements 20-70 or to pass to an auxiliary register an initial entry address for selection from the random access memory. Read out from this memory is used either as an address for future selections within the memory or is compared with data from bus 110. The initial ten character positions in the memory store temporary pointers, address pointers and space counters while the stack holds characters from elements 20-70. Unit 10 has seven basic algorithms which are described with reference to Figs. 4-10 (not shown) and display unit 50 has two modes: write characters to display under operator control or automatic display of stack contents. In the latter the stack can be treated as a linear character string across the cathode-ray tube or each stack parameter can be treated as a separate line where the stack contents are displayed parameter by parameter down the tube face. It is stated that the use of machine language which is directly interpreted eliminates translation or interpretation software.