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.

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

Extended Instruction Mnemonics Overview.

Extended Mnemonics of Branch Instructions.

Extended Mnemonics of Fixed-Point Arithmetic Instructions.

Extended Mnemonics of Fixed-Point Compare Instructions.

Extended Mnemonics of Fixed-Point Load Instructions.

Extended Mnemonics of Fixed-Point Logical Instructions.

Extended Mnemonics of Fixed-Point Trap Instructions.

Extended Mnemonics of Moving from or to Special-Purpose Registers.

Extended Mnemonics of Fixed-Point Rotate and Shift Instructions.

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