Automatic Storage of Contents of P Register (STP)
STP is an operation which occurs whenever control is to be transferred; that is, whenever the next instruction to
be performed is not the one stored immediately following the current instruction. STP automatically stores the
contents of the P Register in standard High Speed Memory locations 0216-0219. The stored address is the address of
the instruction that would have been executed if the transfer of control had not taken place. STP is performed in the
following instructions, but only when control is actually transferred:
Conditional Transfer of Control
Tally
Input/Output Sense
Repeat Instruction
The Repeat Instruction (RPT) will cause the next one of the following instructions to be performed to be
repeated a specified number of times:
Tape- Read Forward Normal
Tape Read Reverse Normal
Add
Transfer Data Left
Transfer Data Right
Subtract
Translate by Table
Transfer Data by Symbol Left
Transfer Data by Symbol Right
Logical "OR"
Exclusive "OR"
Logical "AND"
The number of times a repeatable instruction following an RPT is to be repeated is specified in the N character
of the RPT. If the N character of the RPT is zero, the repeatable instruction will be executed but not repeated. If the
N character of the RPT is one, then the repeatable instruction will be performed twice. Each repeatable instruction,
when repeated, requires three additional status levels (21 microseconds) when the contents of the N
R
(Repeat)
Register exceed zero, and requires one additional status level (7 microseconds) when the contents of the N
R
(Repeat)
Register equal zero.
Simultaneity in the RCA 301 System
Simultaneity in the RCA 301 Computer is defined as the coincident execution of two or three instructions.
Simultaneity is accomplished through the optional control units: the Simultaneous Mode Control Unit and the Record
File Mode Control Unit. When an instruction utilizes the circuitry of the Simultaneous Mode Control Unit it is
progressing in the "Simultaneous Mode." When an instruction utilizes the circuitry of the Record File Mode Control
Unit it is progressing in the "Record File Mode." When an instruction utilizes the Program Control circuitry of the
basic computer it is progressing in the "Normal Mode."
The RCA 301 instructions are designed to operate in one of the three modes. Those instructions designed to
operate in the Normal Mode will operate in that mode only. If a button, called SMDI (Simultaneous Mode Inhibit),
on the Console Panel is not on, those instructions designed to operate in the Simultaneous Mode will operate in that
Mode only. If, however, SMDI is on, simultaneous instructions will operate in the Normal Mode as if they were
Normal instructions and the Store S Register instruction will store the contents of the A Register in STA locations.
Those instructions designed to operate in the Record File Mode will operate in that mode only.
III-6
Содержание 301
Страница 6: ...HRSfOTPflf I I I I ...
Страница 16: ......
Страница 34: ......
Страница 43: ......
Страница 44: ......
Страница 47: ......
Страница 48: ......
Страница 61: ......
Страница 62: ......
Страница 74: ......
Страница 75: ......
Страница 76: ...j I j I I ...
Страница 86: ......
Страница 87: ......
Страница 88: ......
Страница 108: ......
Страница 109: ......
Страница 110: ......
Страница 126: ......
Страница 127: ......
Страница 128: ...X ry V ...
Страница 134: ......
Страница 135: ...INPUT OUTPUT INSTRUCTIONS DATA RECORD FILE INPUT OUTPUT INSTRUCTIONS DATA RECORD FILE XI l ...
Страница 136: ......
Страница 154: ......
Страница 156: ......
Страница 175: ......
Страница 176: ......
Страница 180: ...WWH H i i w m H H J V fi t y v if i Hk I ...
Страница 182: ......
Страница 195: ......
Страница 234: ......
Страница 235: ...d STZ i T J t A p r TTqpe Deivc i L J I 1 G_ F O N _ _ O u I p y f 7 e i o o n p i uj e To o u r p e j C eu ...