Move Words (MVW)/OP=12

Format

OP AF BF A Syllable B Syllable

OP = 12

AFBF length of both operands. A value of 0000 is equal to a length of 10,000 4-digit words or 40,000 digits. AF or BF may be indirect. A literal flag will cause an Invalid Instruction (IEX = 21) fault. See Compatibility Notes A.07.1.

The A Syllable is the address of the source data field. Address may be indexed, indirect or extended. Final address controllers are ignored.
The B Syllable is the address of the destination data field. Address may be indexed, indirect or extended. Final address controllers are ignored.

Note

Use of addresses which are not congruent to zero modulo 4 may produce incompatible results (see Compatibility Notes A.07.2).

Function

The Move Words instruction moves the number of four digit words specified by the concatenation of AF and BF from the source data field in memory to the destination data field in memory.

The contents of the source data field are unchanged (unless A and B partially overlap).

Comparison Flags

The Comparison Flags are unchanged by this instruction.

Overlap

When the final B address is less than the final A address and the fields partially overlap, the source data field will be shifted by that number of digits to the left. When the B data field partially overlaps the A data field and B is greater than A, repeat the data from the A address to the B address throughout the destination data field.

The B data field may totally overlap the A data field.

Examples

Example (1) Move eight digits

OP AFBF A Syllable B Syllable
12 0002 A Field B Field
                    BEFORE              AFTER
   A Field         01020304          01020304
   B Field         nnnnnnnn          01020304
   Comparison Flags   nn              unchanged
   Overflow Flag      nn              unchanged

Example (2) Repeat data field

OP AFBF A Syllable B Syllable
12 0002 A Field A Field + 4
                    BEFORE              AFTER
   A Field        0123nnnnnnnn     012301230123
   Comparison Flags   nn              unchanged
   Overflow Flag      nn              unchanged
instructions/mvw.txt · Last modified: 2009/05/11 08:23 by scott
 
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