IBM 4300 Manual page 271

operand are specified in an even-odd pair of
general registers. Consequently, MVCL can be
used to move more than 256 bytes of data with one
instruction. As an ·example, assume:
Register 2 contains 00 OA 00 00.
Register 3 contains 00 00 08 00.
Register 8 contains 00 06 00 00.
Register 9 contains 00 00 08 00.
Execution of the instruction:
Machine Format
Op Code Rl
OE 8
1
Assembler Format
Op Code R
1
,R2
MVCL 8,2
2
moves 2,048
10
bytes from locations AOOOO-A07FF
to location 60000-607FF. Condition code 0 is set
to indicate that the operand lengths are equal.
If
register 3 had contained FO 00 04 00, only the
1,024
10
bytes from locations AOOOO-A03FF would
have been moved to locations 60000-603FF. The
remaining locations 60400-607FF of the first
operand would have been filled with 1,024 copies
of the padding byte X'FO', as specified by the
leftmost byte of register 3. Condition code 2 is set
to indicate that the first operand is longer than the
second.
The technique for setting a field to zeros that is
illustrated in the second example of MVC cannot
be used with MVCL. If the registers were set up to
attempt such an operation with MVCL, no data
movement would take place and condition code 3
would indicate destructive overlap.
Instead, MVCL may be used to clear a storage
area to zeros as follows. Assume register 8 and 9
are set up as before. Register 3 contains only
zeros, specifying zero length for the second
operand and a zero padding byte. The contents of
register 2 are not significant. Executing the
instruction MVCL 8,2 causes locations
60000-607FF to be filled with zeros. Condition
code 2 is set.
MOVE NUMERICS (MVN)
Two related instructions, MOVE NUMERICS and
MOVE ZONES, may be used with decimal data in
the zoned format to operate separately on the
A-] 8 IBM 4300 Processors Principles of Operation
rightmost four bits (the numeric bits) and'the
leftmost four bits (the zone bits) of each byte.
Both are similar to MOVE (MVC), except that
MOVE NUMERICS moves only the numeric bits
and MOVE ZONES moves only the zone bits.
To illustrate the operation of the MOVE
NUMERICS instruction, assume that the following
two fields are in storage:
7090 7093
Field A IC61C71C81C91
7041 7046
Field B IFOIF11F21F31F41F51
Also assume:
Register 14 contains 00 00 70 90.
Register 15 contains 00 00 70 40.
After the instruction:
Machine Format
Op Code
L
01 03
Assembler Format
Op Code 01(L,B1),02(B2)
MVN 1(4,15),0(14)
is executed, field B becomes:
7041 7046
IF61F71F81F91F41 FS
I
E
I
000\
The numeric bits of the bytes at locations
7090-7093 have been stored in the numeric bits of
the bytes at locations 7041-7044. The -contents of
locations 7090-7093 and 7045-7046 are
unchanged.
MOVE WITH OFFSET (MVO)
MOVE WITH OFFSET may be used to shift a
packed-decimal number an odd number of digit
positions or to concatenate a sign to an unsigned
packed-decimal number.
Assume that the three-byte unsigned
packed-decimal number in storage locations
4500-4502 is to be moved to locations 5600-5603