Propeller Manual

WC – Assembly Language Reference
WC
Effect: Cause assembly instruction to modify the C flag.
〈Label〉 〈Condition〉 Instruction Operands WC
Result: C flag is updated with status from the Instruction‘s execution.
• Label is an optional statement label. See Common Syntax Elements on page 250.
•
Condition is an optional execution condition. See Common Syntax Elements on page 250.
•
Instruction is the desired assembly instruction.
•
Operands is zero, one, or two operands as required by the Instruction.
Explanation
WC (Write C flag) is one of four optional effects (NR, WR, WZ, and WC) that influence the behavior
of assembly instructions.
WC causes an executing assembly instruction to modify the C flag in
accordance with its results.
For example, the
CMP (Compare Unsigned) instruction compares two values (destination and
source) but does not automatically write the results to the C and Z flags. You can determine
if the destination value is less than the source value by using the
CMP instruction with the WC
effect:
cmp value1, value2 WC 'C = 1 if value1 < value2
The above CMP instruction compares value1 with value2 and sets C high (1) if value1 is
less than
value2.
See Effects on page 291 for more information.
Page 372 · Propeller Manual v1.1