| Octal Order Code | Nmenonic | Execution |
|---|---|---|
| 020 | ANDX X N(M) | Logical AND into X A 'logical AND' operation is performed with the contents of X and the contents 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. |
| 021 | ORX X N(M) | Logical INCLUSIVE OR into X A 'logical INCLUSIVE OR' operation is performed with the contents of X and the contents 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. |
| 022 | ERX X N(M) | Logical EXCLUSIVE OR into X A 'logical EXCLUSIVE OR' operation is performed on the contents of X and the contents of N(M), both words being regarded as 24-bit patterns rather than as numeric quantities. The ERX 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. |
| 023 | OBEY N(M) | Obey the Instruction at N The instruction, whose address is specified in N(M), is obeyed as if it occupied the position of the OBEY instruction. A return is then made to the instruction succeeding OBEY, unless the specified instruction was a branch, itself transferring control to some other point. C is not used and remains unchanged. 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. |
| 024 | LDCH X N(M) | Load Character to X In its unmodified form the LDCH instruction will make bits 18 to 23 (the least significant character) of X equal to bits 18 to 23 of N. Bits 0 to 17 of X are cleared. N is unchanged. C is not used and will be left clear. V is not used and remains unchanged. Modification The LDCH instruction has an M field. When modified by an accumulator whose contents takes the form of a character index word, the instruction extracts the character at the character position (n0 to n3) specified by bits 0 and 1 of the index word, from the word specified by the sum of N and bits 9 to 23 of the index word and loads it into bits 18 to 23 of X. In the extended data mode, the least significant 22 bits of N + M are taken as the operand. Bits 0 to 17 of X are cleared. N(M) is unchanged. |
| 025 | LDEX X N(M) | Load Exponent The LDEX instruction causes bits 15 to 23 of X to be made equal to bits 15 to 23 of N(M). Bits 0 to 14 of X are cleared and N(M) is left unchanged. 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. |
| 026 | TXU X N(M) | Test X unequal The TXU instruction tests the contents of the two locations X and N(M) for equality, and sets C if they are not equal. If the words are equal, C is left unchanged. The fact that C is not unset by TXU permits the programmer to compare a complete multi-length quantity, before testing C. C is used and may be set or left unchanged (see above). It is not recommended that this instruction should be used with C set unless by a previous TXU instruction. 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. |
| 027 | TXL X N(M) | Test X Less The TXL instruction causes the contents of X to be compared with those of location N(M). According to the results of the comparision, the state of C is affected as follows: Contents of X less than contents of N(M) : C is set Contents of X equal to contents of N(M) : C is unchanged Contents of X greater than contents of N(M) : C is cleared Since the TXL instruction may be required for use with alphanumeric characters as well as with numbers, all words are considered to be 24-bit positive binary numbers and thus no significance is attributed to the sign bit. Therefore when comparing numbers, this instruction will only indicate the correct relationship between them when either both are positive or both are negative. Otherwise a negative number would always be considered greater than a positive number, as it has a 1-bit in the B0 position. C is used and may be set, cleared or left unchanged (see above). It is not recommended that this instruction should be used with C set unless by a previous TXU instruction. 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. |