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Test Under Mask Instruction (Tm); Data Translation, Translate (Tr) - RCA Spectra 70 Training Manual

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DATA TRANSLATION
The Translate instruction provides the user with the
ability to accept data in 'foreign' code, and translate
and process it in the 'native' code of the computer
being used. The data may then be translated back to
the 'foreign' code by the Translate instruction, if de-
sired, prior to the output operation.
The Translation process employs a table that is ad-
dressed by each data character to be translated. The
binary value of the data character being translated is
added to the addre ss of the 256 -byte translation table.
The character in that position of the table replaces
the data character.
The Translate instruction maybe used for preserving
the security of information being transmitted over
communication lines. Data may be translated in an
unintelligible code by the use of a program and one or
a series of translation tables at the sending location,
and sent to the receiving location where a similar
program and table(s) re-translates the data to its in-
telligible form.
Another use of the Translate instruction is to validate
data. As an example, assume that a ten-character
amount field must contain all numeric (unpacked)
characters.
The numeric characters, hexadecimal FO through
F9, have binary values equal to 24010 to 24910. Thus,
the table could be constructed as follows with all zero
bit-filled bytes in these pOSitions such as the following:
NAME
OPERATION
OPERAND
EDTB
DS
240C
DS
X'OOOOOOOOOOOOOOOOOOOO'
DS
6C
The first 240 and the last 6 bytes of the table would
be filled with 1 bits. Thus, any character in the data
field except an unpacked numeric can address a byte
filled with one bits.
If
the original data field must be preserved, the trans-
lationmaybeperformedfrom a Work area. Assume
the data field has been transferred to a work area
and appears as follows:
(shown in hexadecimal)
WAMT
00 01 02 03 04 05 06 07 08 09
FO FO F2 F7 F6 F3 C3 F2 F8 F1
47
It should be noted that all characters are nume ric
(unpacked) except the hexadecimal C3 in pOSition
2006. Thus, after translation this byte will be filled
with one bits and the others filled with zero bits.
The Translate instruction is written as in the follow-
ing format.
(Assume the translation table begins at
2200.)
HSM BEFORE
EXECUTION
ASSEMBLY
INSTRUCTION
GENERATED
INSTRUCTION
HSM AFTER
EXECUTION
WAMT
02 03 04 05 06 07 08 09
FO FO F2 F7 F6 F3 C3 F2 F8 F1
OPERATION
OPERAND
TR
W AMT(l 0), EDTB
OP
DC 16
1
9 10 1 2 10 100001012
1
0200
General Register 2
==
2000
WAMT
00 01 02 03 04 05 06 07 08 09
00 00 00 00 00 00 FF 00 00 00
The presence of any 1 bits in the translated field in-
dicates that the original data field contained an invalid
character. The field could be tested against a zero-
bit-filled field with a Compare Logical instruction as
follows:
NAME
OPERATION
OPERAND
CLC
WAMT(10) , EDTB+239
BC
X'7',INV
VAL
The Compare Logical instruction tests the field for
all zero bits. The Branch instruction transfers to a
routine for handling a field that is invalid (INV). If
the field is all zero, the routine for handling a field
that is valid (VAL) will be entered.
As another example of the Translate instruction for
validation, assume a field that consists of either
alphabetic or numeric characters. Any other char-
acter would make the field invalid.

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