Methods and apparatus for preventing myocardial infarction, or lessening the sizeseverity of an evolving myocardial infarction, by cooling at least the affected area of the myocardium using an intravascular heat exchange catheter. The execution logic includes a primary logic path configured to perform the arithmetic operation on such operands and a secondary parallel logic path configured to output metadata associated with the result of the arithmetic operation. The blocking transistor drain node is connected to the power transistor drain node. A data valid signal propagating with valid data adds further selection, such that only stages with valid data are stalled.