KSTK_STATUS
KSTK_STATUS(current) |= ST0_CU2;
if (KSTK_STATUS(current) & ST0_CU2) {
KSTK_STATUS(current) &= ~ST0_CU2;
KSTK_STATUS(current) |= ST0_CU1;
KSTK_STATUS(current) |= ST0_FR;
KSTK_STATUS(current) &= ~ST0_FR;
KSTK_STATUS(tsk) &= ~ST0_CU1;
if ((KSTK_STATUS(prev) & ST0_CU2)) { \
KSTK_STATUS(prev) &= ~ST0_CU2; \
if (KSTK_STATUS(next) & ST0_CU2 && \
(!(KSTK_STATUS(prev) & ST0_CU1))) { \
KSTK_STATUS(current) |= (ST0_CU1 | ST0_CU2);
KSTK_STATUS(current) |= ST0_FR;
KSTK_STATUS(current) &= ~ST0_FR;