RCA Spectra 70 Training Manual

INSTRUCTION
The RCA 70/25 Order Code consists of thirty-one
instructions that can be divided into four classes.
1. DATA HANDLING
The data handling instructions allow fo r the
movement of data fields within HSM. Date may be
moved without changing format or it can be packed.
unpacked, or edited for printing during the move-
ment. A translate instruction facilitates code con-
version and data validation.
2. ARITHMETIC INSTRUCTIONS
This set includes .Qecimal Add, Subtract, Mul-
tiply, and Divide instructions, as well as Binary
Add and Subtract operations. It also incorporates
the ability to perform Boolean Operations on bit
structures.
3. DECISION AND CONTROL
The decision and control instructions allow for
the comparing of both Decimal and Binary fields,
and the branching to a location in HSM according to
a Condition Code Indicator. Also included are Branch
and Link and Branch on Count instructions which
simplify subroutine linkage, and control of iterative
coding.
4. INPUT/OUTPUT
This set reads and writes data between the pro-
cessor and all peripheral equipment on-line to the
70/25. It includes the necessary instructions to
control the devices, and to recognize and recover
from error conditions.
DATA MOVEMENT INSTRUCTIONS
Data may be moved from one point in memory to
another with or without change. The changes that
can occur during a moving operation are to pack,
unpack, or to unpack and edit.
MOVE CHARACTER INSTRUCTION
The Move Character instruction transfers one byte
or one word at a time from a sending to a receiving
field. The number of bytes transferred is control-
led by the L Register. When possible the hardware
accesses a word at a time. The L character (sent
to the L Register in the staticizing process) is one
less than the number of characters to be transferred
(in machine format) because (1) the first character
is transferred before the L Register is decremented
24
COMPLEMENT
and (2) the L Register is compared after decrement-
ing to FF16 (1 less than 0016) to terminate the execu-
tion of the instruction.
Example:
Construct an output record by transferring selected
fields from the input area.
Assume that an input record area (INP) is located in
memory at 2000-2099 and an output record area
(OUP) is in2200-2299. An account number, 8 char-
acters, is the first field in each record area.
The following instruction would move the account
number to output record area.
OPERATION OPERAND
MVC OUP(8),INP
or in machine format as:
OP
L
7
2000
10
I
General Register one contains 0000
It should be noted that in assembly format as in
machine format, the second field is the address of
the left end of the sending area. The first address
is the left end of the receiving area.
Based on the example above, assume the field INP
contains the value as shown below.
INP
00
01 02
03
04
05
06
07
20 3
7
0
1
4 9
6 5
The field OUP would be filled with characters from
the INP area as shown below.
OUP
00
01 02 03
04 05 06
07
22
3
7 0
1 4
9
6
5
A
data field may be filled with a given character or
cleared by the Move Character instruction by over-
lapping the receiving field so that it begins one posi-
tion to the right of the sending field. Thus the first

RCA Spectra 70 Specifications

General

Manufacturer	RCA
Model	Spectra 70
Category	Computer Hardware
Word Size	32 bits
Memory	Up to 512 KB
Predecessor	RCA 3301
Successor	RCA Series