RCA 301 Programmer's Reference Manual page 179

S Input/Output Sense (IOS)
General Description
This instruction tests the desired status of the selected device and chooses one of two sequences of instructions.
Format
Operation — S
N — - (minus)
A Address — A specifies the tests to be performed as follows:
0
" 1 " Bit
In
2°
2 1
2
2
4
2
— A A , A
l5 2
B Address — HSM location of the next instruction to be executed if the condition or conditions being tested
are present.
Outline of Operation
The test (or tests) called for by the one bits in A
the conditions tested is present, the contents of the P Register are transferred to STP and the contents of the
B Register are then transferred to the P Register. If no tested condition is present, the next instruction in sequence
will be executed.
Final Register Contents
(A = (A);
)f
(B) = (B).
£
Timing
56 fj.s if a transfer is executed.
42 fj.s if no transfer takes place.
N u m e r i c
E q u i v a l e n t
1 Is the Lister inoperable?
2
Is the Lister busy? (This indicator is set at the start of buffer
loading and remains set until the line is printed. It is also set
when the "Hold" switch is on.)
Is there a low paper condition in any of the supply bins?
4
& Is paper being advanced?
— Must be zeros (000).
3
0
T e st s
Standard Location
STP (on transfer only)
are performed on the device selected by N. If any one of
XlV-5