ICL 1900 Series Computers

Order Codes 12x

Octal Order Code Nmenonic Execution
120 ANDN  X  N(M) Logical AND Direct Operand into X

A 'logical AND' operation is performed with the contents of X and the value of N(M), both words being regarded as 24-bit patterns rather than as numeric quantities. A 1-bit is placed in each bit position of X where both X and N(M) have a 1-bit; all other bits of X are set to zero. The contents of N(M) are unaltered.

C is not used and will be left clear.

V is not used and remains unchanged.

Modification This statement has an M field. When modified, the least significant 15 bits of N + M are taken as the operand. In the extended data mode, the least significant 22 bits of N + M are taken as the operand.
121 ORN  X  N(M) Logical INCLUSIVE OR Direct Operand into X

A 'logical INCLUSIVE OR' operation is performed with the contents of X and the value of N(M), both words being regarded as 24-bit patterns rather than as numeric quantities. A 1-bit is placed in each bit position of X where either X or N(M), or both, have a 1-bit. The contents of N(M) are unaltered.

C is not used and will be left clear.

V is not used and remains unchanged.

Modification This statement has an M field. When modified, the least significant 15 bits of N + M are taken as the operand. In the extended data mode, the least significant 22 bits of N + M are taken as the operand.
122 ERN  X  N(M) Logical EXCLUSIVE OR Direct Operand into X

A 'logical EXCLUSIVE OR' operation is performed on the contents of X and the value of N(M), both words being regarded as 24-bit patterns rather than as numeric quantities. The ERN instruction places a 1-bit in X only where the corresponding bits of X and N(M) are different. The contents of N(M) are unaltered.

C is not used and will be left clear.

V is not used and remains unchanged.

Modification This statement has an M field. When modified, the least significant 15 bits of N + M are taken as the operand. In the extended data mode, the least significant 22 bits of N + M are taken as the operand.
123 NULL No Operation

None.

C is not used and remains unchanged.

V is not used and remains unchanged.

Modification The NULL statement has an M field.
124 LDCT  X  N(M) Load Count

The LDCT instruction sets a count in bits 0 to 8 of X equal to the value specified by the least significant 9 bits of N(M). The remainder of X (bits 9 to 23) is cleared.

C is not used and will be left clear.

V is not used and remains unchanged.

Modification The LDCT statement has an M field. When modified, the count set will be the least significant nine bits of N + M.
125 MODE    N(M) Set Zero-Suppression Mode

Before a binary number is converted to decimal characters by use of the CBD, the MODE function indicates whether or not zero-suppression is required.

The non-significant zeros are suppressed (i.e. converted to space characters) if N(M) = 1.

The non-significant zeros are not suppressed if N(M) = 0.

The mode should not be set to any value other than zero or one.

After converting the first non-zero character during the CBD instruction, the mode is reset to zero, so that any subsequent zeros will not be converted to spaces.

C is not used and will be left clear.

V is not used and remains unchanged.

Modification This statement has an M field. When modified, the least significant 15 bits of N + M are taken as the operand. In the extended data mode, the least significant 22 bits of N + M are taken as the operand.
126 MOVE  X  N(M) Copy N Words from the Address in X to the Address in X*

The MOVE instruction copies the word whose address is specified in the least significant 15 bits of X into the address specified in the least significant 15 bits of X*. Both addresses are then incremented by 1, and the procedure repeated until a total of N words have been transferred. In extended data mode, the least significant 22 bits of X and X* are taken as the addresses specified.

The original addresses in X and X* remain unchanged after execution, unless included in the area into which copying is specified. A count of zero causes 512 words to be moved.

C is not used and will be left clear.

V is not used and remains unchanged.

Modification This statement has an M field. When modified, the least significant 15 bits of N + M are taken as the operand. In the extended data mode, the least significant 22 bits of N + M are taken as the operand.
127 SUM Sum N Words

The SUM instruction replaces the previous contents of X with the sum of N consecutive locations. The address of the first location is contained in the least significant 15 bits of X* (in the extended data mode, the least significant 22 bits of X*). If the sum exceeds the capacity of one word, then bits will be lost from the more significant end but V will not be set.

C is not used and will be left clear.

V is not used and remains unchanged.

Modification This statement has an M field. When modified, the least significant 15 bits of N + M are taken as the operand. In the extended data mode, the least significant 22 bits of N + M are taken as the operand.