[ECOS] About Call-pending-DSRs

[windy]

Referring to eCos Interrupt Model in eCos document , it allow irq recur when call DSR.
But in ARM implement code(vector.s), I found the irq haven't be re-enable immediately
after calling isr handle. if enable MACRO CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK,
ECOS will enable irq and call dsr continue,if we haven't enable this MACRO,ecos will call 
dsr directly without enabling irq. 
What if I enable irq directly after calling isr handle?

Best Regards
 Windy