RSEG ICODE:CODE
        CODE32

        EXTERN vUSB_ISR
        PUBLIC vUSB_ISREntry

vUSB_ISREntry:

    portSAVE_CONTEXT        ; Save the context of the current task.

    LDR R0, =vUSB_ISR
    mov     lr, pc
    BX R0

    portRESTORE_CONTEXT        ; Restore the context of the current task -
                            ; which may be different to the task that
                            ; was interrupted.
        END

BOOL USB_isr()
{
    if (USBINTS & 0x00000008)
    {
        u32 int_status    = HCINTERRUPTSTATUS;
        u32 ie_status     = HCINTERRUPTENABLE;

        if (!(int_status & ie_status))
            return FALSE;
        else
        {
            int_status = int_status & ie_status;
            if (int_status & OR_INTR_STATUS_RHSC)
            {                 /* Root hub status change interrupt     */
                if (HCRHPORTSTATUS1 & OR_RH_PORT_CSC)
                {
                    if (HCRHPORTSTATUS1 & OR_RH_PORT_CCS)
                        HOST_RhscIntr = 1;
                    else
                        HOST_RhscIntr = 0;
                    HCRHPORTSTATUS1 = OR_RH_PORT_CSC;
                }
                if (HCRHPORTSTATUS1 & OR_RH_PORT_PRSC)
                    HCRHPORTSTATUS1 = OR_RH_PORT_PRSC;
            }
            if (int_status & OR_INTR_STATUS_WDH)  // Writeback Done Head interrupt
                HOST_WdhIntr = 1;
            HCINTERRUPTSTATUS = int_status;   // Clear interrupt status register
        }
    }

    return FALSE; // context switch?
}

// ********************************************************************
// ********************************************************************
// USB ISR.  This can cause a context switch
// The interrupt service routine - called from the assembly entry point.
extern "C" void vUSB_ISR( void );
void vUSB_ISR( void )
{
    // If a task was woken by either a character being received or a character
    // being transmitted then we may need to switch to another task.
    portEND_SWITCHING_ISR(USB_isr());

    // End the interrupt in the EIC
    VICADDRESS = 0; // clear interrupt
}