Reference Information; Condensed Logic; Adders; Address Register - IBM 7090 Instruction-Reference

7. O. 00 REFERENCE INFORMATION
7.1.00 CONDENSED LOOIC
7.1.01 Adders (Systems 02.02.01.1-02.02.37.1)
The adders consist of transistor switching circuits for combining binary numbers
into a binary sum. The 7090 can only add, therefore control lines are needed to develop
true and complement conditions.
ACC to ADD
SR to ADD
XR to ADD
COMP ACC to ADD
02.12.24.1
02.12.17.1
02.12.19.1
02.12.23.1
Adders are used for many different types of operations and some controls will affect
only certain adders. The adders have three types of outputs: sum, carry, and looka-
head. Section 3 covers the theory of the adder outputs.
7.1.02 Address Register (Systems 03.06.00.1-03.06.04.1)
The address register is a 15-position register of triggers.
It
is labeled 3 through
17. The address register signals the desired address to the core control circuits
(Figure 7.1-1). Control lines for the address register are:
Address Switches to AR
AR to PC
03.06.05.1
03.06.05.1
7.1.03 Program Register (Systems 03.04.00.1-03.04.03.1)
The program register is made up of ten positions, and is used for decoding the
instructions during I time. Lines controlling the input and output of the program register
(Figure 7.1-2) are:
SR to PR
OPKto PR
SB to PR
Reset PR
02.11. 40.1
02.12.09.1
02.05.10.1
02.11.40.1
7.1. 04 Sense Indicators (Systems 02.06.00.1-02.06.35.1)
The sense indicator register is a 36-position register of triggers. There are two
triggers to each position (Figure 7. 1-3) . Lines controlling the sense indicators are:
Invert SI
Set IND
COMP SI to SR
SI to SR
02.12.61.1
02.12.63.1
02.12.12.1
02.12.62.1
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