Interrupt Issues, PIC12HV615 HI-TECH Compiler

#include <pic.h>
#include <htc.h>

void init(void)
{
    TRISIO=0b00000011;            //set GPIO<1:0> as inputs
    GPIO=0b11111111;              //set GPIO high
    IOC=0b00000011;               //enable ICO GP0 and GP1
    INTCON = 0b10001000;          //enable interrupt on change and global interrupts
}

volatile unsigned char zero;      //initilise global var flag zero
volatile unsigned char one;       //initilise global var flag one
#define SET 1
#define UNSET 0
#define _XTAL_FREQ 8000000

main()
{
    init();                       //initilise registers
    zero=UNSET;                   //unset flag
    one=UNSET;                    //unset flag
    ei();                         //enable interrupts
    while(1)                      //wait for a flag to be set by interrupt
    {
        if(zero == SET)
        {
            GP4=0;                //set GP4 low
            zero=UNSET;           //unset flag
        }
        if(one == SET)
        {
            GP4 = 1;              //set GP4 high
            one=UNSET;            //unset flag
        }

    }

}

void interrupt my_isr(void)
{
    di();                         //disable interrupts
    if(GP0 == 0)                  //set correct flag
       zero=SET;
    if(GP1 == 0)
       one=SET;
    __delay_us(90);
    ei();                         //enable interrupts
}

#include <pic.h>
#include <htc.h>

void init(void)
{
    TRISIO=0b00000011; //set GPIO<1:0> as inputs
    GPIO=0b11111111; //set GPIO high
    IOC=0b00000011; //enable ICO GP0 and GP1
    INTCON = 0b10001000; //enable interrupt on change and global interrupts
}

volatile unsigned char zero; //initilise global var flag zero
volatile unsigned char one; //initilise global var flag one
#define SET 1
#define UNSET 0
#define _XTAL_FREQ 8000000

main()
{
    init(); //initilise registers
    zero=UNSET; //unset flag
    one=UNSET; //unset flag
    //ei(); //enable interrupts
    while(1) //wait for a flag to be set by interrupt
    {
        if(zero == SET)
        {
            GP4=0; //set GP4 low
            zero=UNSET; //unset flag
        }
        if(one == SET)
        {
            GP4 = 1; //set GP4 high
            one=UNSET; //unset flag
        }
    }
}


void interrupt my_isr(void)
{
    //di(); //disable interrupts
    if(GP0 == 0) //set correct flag
        zero=SET;
    if(GP1 == 0)
        one=SET;
    __delay_us(90);
    //ei(); //enable interrupts
}