Effect: Prevent assembly instruction from writing a result.

< Label > < Condition > Instruction Operands NR

Result: Instruction's destination register is left unaffected.

• Label is an optional statement label. See Common Syntax Elements.
• Condition is an optional execution condition. See Common Syntax Elements.
• Instruction is the desired assembly instruction.
• Operands is zero, one, or two operands as required by the Instruction.

Explanation

NR (No Result) is one of four optional effects (WC, WZ, WR, and NR) that influence the behavior of assembly instructions. NR causes an executing assembly instruction to leave the destination register's value unaffected.

For example, by default the SHL (Shift Left) instruction shifts the destination value left a number of bits, writes the result back into the destination register, and optionally indicates status via the C and Z flags. If all that you really need is the SHL instruction's C flag status, simply specify it with both the WC and NR effects:

shl    value, #1    WC, NR    'Put value's MSB in C 

The above example effectively sets the C flag to the state of value's high bit (bit 31) without affecting the final contents of value.

See Effects (WC, WZ, WR, NR) for more information.