UNIVAC 1100/2200 series

Architecture

Instruction format

Instructions are 36 bits long with the following fields:

f ( 6 bits) - function designator (opcode),

j ( 4 bits) - partial word designator, J-register designator, or minor function designator,

a ( 4 bits) - register (A, X, or R) designator or I/O designator,

x ( 4 bits) - index register designator,

h ( 1 bit ) - index register increment designator,

i ( 1 bit ) - indirect address designator,

u (16 bits) - address or operand designator.

Registers

The 128 registers of the high speed "general register stack", map to the current data space in main storage starting at memory address zero. These registers include both user and executive copys of the A, X, R, and J registers and many special function executive registers.

The table on the right shows the addresses (in octal) of the user registers.

There are 15 index registers (X1 ... X15), 16 accumulators (A0 ... A15), and 15 special function user registers (R1 .. R15). The 4 J registers and 3 "staging registers" are uses of some of the special function R registers.

One interesting feature is that the last 4 index registers (X12 ... X15) and the first 4 accumulators (A0 ... A3) overlap, allowing data to be interpreted either way in these registers. This also results in 4 unassigned accumulators (A15+1 ... A15+4) that can only be accessed by their memory address (double word instructions on A15 do operate on A15+1).

UNIVAC 1100 series

1. UNIVAC 1107 introduced in 1962
2. UNIVAC 1108 introduced in 1964
3. UNIVAC 1106 introduced in 1969
4. UNIVAC 1110 introduced in 1972
5. UNIVAC 1100/10[?] introduced in 1975
6. UNIVAC 1100/12[?] introduced in 1975
7. UNIVAC 1100/20 redesignation of UNIVAC 1106 in 1975
8. UNIVAC 1100/40 redesignation of UNIVAC 1110 in 1975
9. UNIVAC 1100/181[?] introduced in 1975
10. UNIVAC 1100/80[?] introduced in 1978
11. UNIVAC 1100/60[?] introduced in 1979
12. UNIVAC 1100/61[?] introduced in 1979
13. UNIVAC 1100/62[?] introduced in 1981
14. UNIVAC 1100/63[?] introduced in 1981
15. UNIVAC 1100/64[?] introduced in 1981
16. UNIVAC 1100/70[?] introduced in 1981
17. UNIVAC 1100/90[?] introduced in 1982
18. UNIVAC 1100/91[?] introduced in 1982
19. UNIVAC 1100/92[?] introduced in 1982
20. UNIVAC 1100/93[?] introduced in 1982
21. UNIVAC 1100/94[?] introduced in 1982

SPERRY 2200 series

In 1983 Sperry Corporation discontinued usage of the name UNIVAC for their products.

1. SPERRY 2200/100[?] introduced in 1985

UNISYS 2200 series

In 1986 Sperry Corporation merges with Burroughs Corporation to become Unisys Corporation.

1. UNISYS 2200/200[?] introduced in 1986
2. UNISYS 1100/94[?] introduced in 1987
3. UNISYS 2200/400[?] introduced in 1988
4. UNISYS 1100/91[?] introduced in 1988
5. UNISYS 1100/92[?] introduced in 1988
6. UNISYS 2200/600[?] introduced in 1989
7. UNISYS 2200/100[?] introduced in 1990
8. UNISYS 2200/500[?] introduced in 1993
9. UNISYS 2200/900[?] introduced in 1993
10. UNISYS 2200/3800[?] introduced in 1997

External link

• UNIVAC® Memories (http://www.fourmilab.ch/documents/univac/)