ICL 1900 Series Computers

Order Codes 00x

Octal Order Code Nmenonic Execution
000 LDX  X  N(M) Load to X

The contents of N(M) are loaded into X. If C was left set by the previous instruction, 1 is added to the result in X. The contents of N(M) are unaltered.

C is used and will be left clear.

V will be set if N(M) contains #37777777 and C was set when the LDX instruction came to be obeyed.

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.
001 ADX  X  N(M) Add into X

The contents of N(M) are added to the contents of X; if C was left set by the previous instruction, 1 is added to the result in X. The contents of N(M) are unaltered.

C is used and will be left clear.

V will be set if overflow occurs.

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.
002 NGX  X  N(M) Negative Load into X

The complement of the contents of N(M) is placed in X. If C was left set by the previous instruction, 1 is subtracted from the result in X. The contents of N(M) are unaltered.

C is used and will be left clear.

V will be set if N(M) contains #40000000 and C was not set initially.

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.
003 SBX  X  N(M) Subtract from X

The contents of N(M) are subtracted from the contents of X. If C was left set by the previous instruction, 1 is subtracted from the result in X. The contents of N(M) are unaltered.

C is used and will be left clear.

V will be set if overflow occurs.

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.
004 LDXC  X  N(M) Load into X with Carry

The contents of N(M) are loaded into X. If C was left set by the previous instruction, 1 is added to the result in X. At the conclusion of this instruction, B0 of the result will always be zero. The contents of N(M) are unaltered.

C is used and will be set if carry occurs.

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.
005 ADXC  X  N(M) Add into X with Carry

The contents of N(M) are added to the contents of X; if C was left set by the previous instruction, 1 is added to the result in X. At the conclusion of this instruction, B0 of the result will always be zero. The contents of N(M) are unaltered.

C is used and will be set if carry occurs.

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.
006 NGXC  X  N(M) Negative Load into X with Carry

The complement of the contents of N(M) is placed in X. If C was left set by the previous instruction, 1 is subtracted from the result in X. The contents of N(M) are unaltered.

C is used and will be set if carry occurs.

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.
007 SBXC  X  N(M) Subtract from X with Carry

The contents of N(M) are subtracted from the contents of X. If C was left set by the previous instruction, 1 is subtracted from the result in X. At the conclusion of this instruction, B0 of the result will always be zero. The contents of N(M) are unaltered.

C is used and will be set if carry occurs.

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.