Chapter 13 UNIVAC Scientific (1103A) instruction logic 207
44 Q-Jump QJuv: If Q35 = 1, take (u) as NI. If Q35 = 0, take (v) as NI. Then, in either case, left circular shift (Q) by one place.
One-way Conditional jump instructions
41 Index Jump IJuv: Form in A the difference D(u) minus 1. Then if A71 = 1, continue the present sequence of instructions; if A71 = 0, replace (u) with (AR) and take (v) as NI.
42 Threshold Jump TJuv: If D(u) is greater than (A), take (v) as NI; if not, continue the present sequence. In either case, leave (A) in its initial state.
43 Equality Jump EJuv: If D(u) equals (A), take (v) as NI, if not, continue the present sequence. In either case leave (A) in its initial state.
One-way unconditional jump instructions
45 Manually Selective Jump MJjv: If the number j is zero, take (v) as NI. If j is 1, 2, or 3, and the correspondingly numbered MJ selecting switch is set to "jump," take (v) as NI; if this switch is not set to "jump," continue the present sequence.
37 Return Jump RJuv: Let y represent the address from which CI was obtained. Replace the right-hand 15 bits of (u) with the quantity y plus 1. Then take (v) as NI.
14 Interpret IP: Let y represent the address from which CI was obtained. Replace the right-hand 15 bits of (F1) with the quantity y + 1. Then take (F2) as NI.
Stop instructions
56 Manually Selective Stop MSjv: If j = 0, stop computer operation and provide suitable indication. If j = 1, 2, or 3 and the correspondingly numbered MS selecting switch is set to "stop," stop computer operation and provide suitable indication. Whether or not a stop occurs, (v) is NI.
57 Program Stop PS-Stop computer operations and provide suitable indication.
External equipment instructions
17 External Function EF-v: Select a unit of external equipment and perform the function designated by (v).
76 External Read ERjv: If j = 0, replace the right-hand 8 bits of (v) with (IOA); if j = 1, replace (v) with (IOB).
77 External Write EWjv: If j = 0, replace (IOA) with the right-hand 8 bits of (v); if j = 1, replace (IOB) with (v). Cause the previously selected unit to respond to the information in IOA or IOB.
61 PRint PR-v: Replace (TWR) with the right-hand 6 bits of (v). Cause the typewriter to print the character corresponding to the 6-bit code.
63 PUnch PUjv: Replace (HPR) with the right-hand 6 bits of (v). Cause the punch to respond to (HPR). If j = 0, omit seventh level hole; if j = 1, include seventh level hole.
Arithmetic instructions
71 Multiply MPuv: Form in A the 72-bit product of (u) and (v), leaving in Q the multiplier (u).
72 Multiply Add MAuv: Add to (A) the 72-bit product of (u) and (v), leaving in Q the multiplier (u).
73 Divide DVuv: Divide the 72-bit number (A) by (u), putting the quotient in Q, and leaving in A a non-negative remainder R. Then replace (v) by (Q). The quotient and remainder are defined by: (A)i = (u) . (Q) + R, where 0 £ R < ÷ (u)÷ . Here (A)i denotes the initial contents of A.
74 Scale Factor SFuv: Replace (A) with D(u). Then left circular shift (A) by 36 places. Then continue to shift (A) until A34 ¹ A35. Then replace the right-hand 15 bits of (v) with the number of left circular shifts, k, which would be necessary to return (A) to its original position. If (A) is all ones or zeros, k = 37. If u is A, (A) is left unchanged in the first step, instead of being replaced by D(AR).
Sequenced instructions
75 RePeat RPjnw: This instruction calls for the next instruction, which will be called NIuv, to be executed n times, its u and v addresses being modified or not according to the value of j. Afterwards the program is continued by the execution of the instruction stored at a fixed address F1. The exact steps carried out are:
a Replace the right-hand 15 bits of (F1) with the address w.
b Execute NIuv, the next instruction in the program, n times.