bonus in case of salary breakup

hi,

if a co. revise salary of its employees and the break up of salary twice (1 time in first Qtr. and second time in II Qtr.during the year) whether bonus will provide only as per basic salary or the co. may pay bonus more than one month salary. whether  there  are some  restriction in  amendments for second time in salary break up

Thanks and Regards

Abid Hussain