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# Univac M460

Program-Transformation.Org: The Program Transformation Wiki
250 Machine-Independent Computer Programming

```
TABLE XIII
MACHINE LANGUAGE INSTRUCTION REPERTOIRE OF THE
UNIVAC M-46O COUNTESS COMPUTER
```
```FF   Function                            FF   Function
00   Illegal                             40   Enter logical product
01   Shift Q right                       41   Add logical product
02   Shift A right                       42   Subtract logical product
03   Shift AQ right                      43   Mask comparison
04   Compare                             44   Replace logical product
05   Shift Q left                        45   Replace add logical product
06   Shift A left                        46   Replace subtract logical product
07   Shift AQ left                       47   Store logical product
10   Enter Q register                    50   Selective set
11   Enter accumulator                   51   Selective complement
12   Enter B register                    52   Selective clear
13   Enter C register                    53   Substitute
14   Store Q register                    54   Replace selective set
15   Store accumulator                   55   Replace selective complement
16   Store B register                    56   Replace selective clear
17   Store C register                    57   Replace substitute
21   Subtract                            61   Manual jump
22   Multiply                            62   Input jump
23   Divide                              63   Output jump
24   Add replace                         64   Arithmetic return jump
25   Subtract replace                    65   Manual return jump
26   Q add                               66   Input return jump
27   Q subtract                          67   Output return jump
31   Load A subtract Q                   71   Index skip
32   Add Q and store                     72   Index jump
33   Subtract Q and store                73   Initiate input transfer
34   Replace add Q                       74   Initiate output transfer
35   Replace subtract Q                  75   Initiate input buffer
36   Replace add one                     76   Initiate output buffer
37   Replace subtract one                77   Illegal.
```

Here are MikeVanEmmerik's guesses for the j, k, and b fields:

j = branch condition
0 never
1 ?
2
3
4 equal to 0
5 not equal to 0
6 >= 0
7 < 0

k = operand interpreter
0 immediate yyyyy
1 indirect memory m[m[yyyyy]] ?
2
3 direct memory m[yyyyy]
4
5
6
7

b = index designator
0 no index
1 b
2
3
4
5
6
7