Questions tagged [besm-6]

The BESM-6 was a Soviet computer, designed in the 1960s and in production from 1968 to 1987 in various forms.

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1answer
200 views

Was dynamic type check in Pascal commonplace?

The BESM-6 Pascal compiler I'm experimenting with has a notable difference from Standard Pascal: formal arguments of formal parameters-procedures or functions are not specified, but are checked at ...
8
votes
0answers
347 views

What is the timeline of NASA ground control computers?

In the movie "Hidden Figures", NASA receives an IBM 7090 in 1961. What is the subsequent timeline of the primary computing means for flight planning and orbit calculation? Specifically, what was the ...
6
votes
3answers
961 views

Was there a Western computer with blatantly missing instructions in the instruction set?

In the BESM-6, there is an instruction (045) to add index registers, but not to subtract them, however, there is a nearby unused opcode 047, which is made synonymous to 045 (in fairness, that's true ...
8
votes
1answer
411 views

How can floating point addition be so slow on a BESM-6?

In the BESM-6 technical manuals — for example, in the ALU description, page 4 — there is a table specifying min/max/average instruction latencies in clock cycles (the last 3 columns; the ...
7
votes
4answers
500 views

Which CPUs had instructions leaving data registers in an unspecified state?

When an ALU performs a floating point division operation using the non-restoring or the SRT algorithm, it maintains the current value of the "remainder" (in quotes, because it is not a true non-...
6
votes
2answers
930 views

What is the purpose of the ω register of the БЭСМ-6?

This page describing the БЭСМ-6 instruction set refers to a value called ω, which is stored inside a Mode Register. It appears to be set by certain kinds of instructions, so that ω can tell you which ...