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AIX Version 4.3 Assembler Language Reference

## Extended Mnemonics of Condition Register Logical Instructions

Extended mnemonics of condition register logical instructions are available in POWER and PowerPC. These extended mnemonics are in the com assembly mode. Condition register logical instructions can be used to perform the following operations on a given condition register bit.

• Set bit to 1.
• Clear bit to 0.
• Copy bit.
• Invert bit.

The extended mnemonics shown in the following table allow these operations to be easily coded.

 Condition Register Logical Instruction Extended Mnemonics Extended Mnemonic Equivalent to Meaning crset bx creqv bx, bx, bx Condition register set crclr bx crxor bx, bx, bx Condition register clear crmove bx, by cror bx, by, by Condition register move crnot bx, by crnor bx, by, by Condition register NOT

Since the condition register logical instructions perform the operation on the condition register bit, the assembler supports expressions in all input operands. When using a symbol name to indicate a condition register (CR) field, the symbol name should be multiplied by four to get the correct CR bit, because each CR field has four bits.

### Examples

1. To clear the SO bit (bit 3) of CR0:
`crclr   so`
This is equivalent to:
`crxor 3, 3, 3`
2. To clear the EQ bit of CR3:
`crclr   4*cr3+eq`
This is equivalent to:
`crxor   14, 14, 14`
3. To invert the EQ bit of CR4 and place the result in the SO bit of CR5:
`crnot   4*cr5+so, 4*cr4+eq`
This is equivalent to:
`crnor   23, 18, 18`

### Related Information

The creqv (Condition Register Equivalent) instruction, cror (Condition Register OR) instruction, crnor (Condition Register NOR) instruction, crxor (Condition Register XOR) instruction.

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