INTERCOM 1000 (80/int014) |
 |
Autocode for the Bendix G-15
Multiple precision floating point autocode for the Bendix G-15
Hardware:
- Bendix G-15 Bendix
Related languages
| INTERCOM 101 | => | INTERCOM 1000 | Evolution of |
References:
Bob Bemer states that this table (which appeared sporadically in CACM) was partly used as a space filler. The last version was enshrined in Sammet (1969) and the attribution there is normally misquoted.
in [ACM] CACM 2(05) May 1959 view details
INTRODUCTION
lntercom 1000 is an easy-to-use programming system which does not require specialized knowledge. Completely self-contained, it has facilities for computer control, input, output and program checking as well as program preparation.
A single lntercom command causes execution of a number of internal operations in the computer. Since the programmer need have no knowledge of the varied internal operations performed by each lntercom command, and programmer. In Intercom 1000 Double-Precision, memory locations numbered from 0900 to 1899, inclusive, may be used by the programmer. The memory locations not available to the programmer are used by the computer to hold instructions which control the operation of the lntercom system.
A command may be stored at, and executed from, any available address.
A numerical value also may be stored at any address in lntercom 1000 Single-Precision.
Since decimal points in numbers are handled automatically, a numerical value may be stored at any even-numbered the time and skill required for programming is greatly address in lntercom 1000 Double-Precision. The numerical reduced, value will occupy the even-numbered location specified command structure by the address and the immediately subsequent oddnumbered one.
The computer is given its instructions in the form of Additional data and command storage is provided by numerically expressed commands which can be held in punched paper tape. An Intercom command permits any the internal memory. Each command is expressed by portion of the internal memory to be punched on paper seven digits. tape at any time during the program; a second command permits punched paper tape to be read into the memory at high speed at any time during the program.
FORM OF A COMMAND
Index Operation
Register Code
Address
The first digit represents an index register; if no index register is used, the first digit is zero and need not be written. lndex registers simplify the programming of automatic address modification and need be considered only when this feature is desired.
The next two digits consist of a code that specifies the operation to be performed. The operation codes are listed at the end of the manual.
The last four digits normally specify the location in the memory to which the operation refers.
Commands are normally obeyed in the numerical sequence of their memory locations. The computer is told the address of the first command to be obeyed. After execution of this command, the computer will automatically obey, in turn, the command in each following address.
Commands are available which transfer control to a command other than the next one in sequence. The computer will then obey commands in the new sequence.
A command to transfer control may be unconditional or may be contingent on the nature of a calculated value.
The address of the transfer of control command may, if desired, be remembered by the computer in order to return control later to the original command sequence.
There are two "Mark Place and Transfer Control" commands for this purpose. For each of these two commands there is a "Return" command which transfers control back to the location immediately following the last corresponding "Mark Place and Transfer Control" command.
The Bendix G-15 Computer uses a magnetic drum for its internal memory.
The two pairs of such commands make it possible to incorporate two levels of sub-program operation; that is, a first "Mark Place and Transfer" command can transfer control to a separate sequence of commands, and while in that subprogram, the second "Mark Place and Transfer" command can transfer control to still another sequence of internal memory command sequences.
A location in the memory of the covputer is specified by a four-digit number called an "address." The first two digits refer to a channel on the magnetic drum; the last two digits refer to the word position in the channel.
In Intercom 1000 Single-Precision, memory locations numbered from 0700 to 1899, inclusive, may be used by the commands.
in [ACM] CACM 2(05) May 1959 view details
in [ACM] CACM 2(05) May 1959 view details
Resources
- Bendix documentation for a restoration project in Western Australia
external link - Intercom logo