RCA 70/46 User Manual

Set Condition Code To 3 and
Terminate Start Device
Instruction
Next Instruction
(I/O Operation Not Initiated)
Set Program Check Bit in
Channel Status Byte
Set Condition Code to 1
and Terminate Start Device
Instruction
Next Instruction
(1'0 Operation Not Initiated)
2
No
3
4
5
No
6
No
7
No
START
Is Privi leged
Mode Bit Set To
Zero?
Yes
Is Specified
Selector Channel
On System?
Yes
Is Specified Channel:
1. Busy Selector
2. Selector with Interrupt
Pending
3. Multiplexor In aurst
No
Reset the Channel Status
Byte and the Standard Device
Byte to Zero
If the Memory Protect
Feature is Not Installed:
Is Key in CAW = O?
Yes
Is Main Memory Address
in CAW on a Double Word
Boundary?
Yes
Is Main Memory Address
in CCW in Avai lable
Main Memory?
Yes
Yes
Input/Output Operation
Set Condition Code to 2
and Terminate Start Device
In stru ct ion
Next Instruction
(I/O Operation Not Initiated)
Figure S. Functional Logic of Start Device Instruction
48

RCA 70/46 Specifications

General

Brand	RCA
Model	70/46
Category	Computer Hardware
Language	English