Effect: Cause assembly instruction to write a result.

< Label > < Condition > Instruction Operands WR

Result: Instruction's destination register is changed to the result value.

• 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

WR (Write Result) is one of four optional effects (WC, WZ, NR, and WR) that influence the behavior of assembly instructions. WR causes an executing assembly instruction to write its result value to the destination register.

For example, by default the COGINIT (Cog Initialize) instruction does not write a result to the destination register. This is fine when wanting to start a cog with a specific ID, but when asking to start the next available cog (i.e., destination register value bit 3 is high) you may like to know what cog was actually started, by ID. You can get the new cog's ID from the COGINIT instruction by using the WR effect:

coginit    launch_value    WR    'Launch new cog, get ID back 

Assuming launch_value points to a register that contained a high (1) in bit 3, the COGINIT instruction starts the next available cog and writes its ID back to the launch_value register.

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