I'm using Keil version 3.2 .You can set or clear bit of Port 1 by declare variable as

sbit P1_0 = 0x90 ;
sbit P1_1 = 0x91 ;
.
.
.
sbit P1_7 = 0x97 ;
main()
{
P1_0 = 1 ;// Set P1.0
p1_1 = 0 ;// Clear P1.1
}