STACK_INT_FRAME_MARKER
#define STACK_INT_FRAME_MARKER_LONGS (STACK_INT_FRAME_MARKER/sizeof(long))
stw r10,STACK_INT_FRAME_MARKER(r1)
stw r10, STACK_INT_FRAME_MARKER(r1)
*(unsigned long *)(sp + STACK_INT_FRAME_MARKER) = STACK_FRAME_REGS_MARKER;
if (mread(sp + STACK_INT_FRAME_MARKER, &marker, sizeof(unsigned long))