IMPORT  _tx_thread_system_stack_ptr
    IMPORT  _tx_initialize_unused_memory
    IMPORT  _tx_timer_interrupt
	IMPORT  __main
    IMPORT  __initial_sp
    IMPORT  __Vectors

SYSTEM_CLOCK        EQU     72000000
SYSTICK_CYCLES      EQU     ((SYSTEM_CLOCK / 1000) -1)

    AREA ||.text||, CODE, READONLY

;VOID   _tx_initialize_low_level(VOID)
;{
    EXPORT  _tx_initialize_low_level
_tx_initialize_low_level
;
;    /* Disable interrupts during ThreadX initialization.  */
;
    CPSID   i
;
;    /* Set base of available memory to end of non-initialised RAM area.  */
;
    LDR     r0, =_tx_initialize_unused_memory   ; Build address of unused memory pointer
    LDR     r1, =__initial_sp		            ; Build first free address
    ADD     r1, r1, #4                          ;
    STR     r1, [r0]                            ; Setup first unused memory pointer
;
;    /* Setup Vector Table Offset Register.  */
;
    MOV     r0, #0xE000E000                     ; Build address of NVIC registers
    LDR     r1, =__Vectors                   	; Pickup address of vector table
    STR     r1, [r0, #0xD08]                    ; Set vector table address
;
;    /* Enable the cycle count register.  */
;
;    LDR     r0, =0xE0001000                     ; Build address of DWT register
;    LDR     r1, [r0]                            ; Pickup the current value
;    ORR     r1, r1, #1                          ; Set the CYCCNTENA bit
;    STR     r1, [r0]                            ; Enable the cycle count register
;
;    /* Set system stack pointer from vector value.  */
;
    LDR     r0, =_tx_thread_system_stack_ptr    ; Build address of system stack pointer
    LDR     r1, =__Vectors                   	; Pickup address of vector table
    LDR     r1, [r1]                            ; Pickup reset stack pointer
    STR     r1, [r0]                            ; Save system stack pointer
;
;    /* Configure SysTick for 100Hz clock, or 16384 cycles if no reference.  */
;
    MOV     r0, #0xE000E000                     ; Build address of NVIC registers
    LDR     r1, =SYSTICK_CYCLES
    STR     r1, [r0, #0x14]                     ; Setup SysTick Reload Value
    MOV     r1, #0x7                            ; Build SysTick Control Enable Value
    STR     r1, [r0, #0x10]                     ; Setup SysTick Control
;
;    /* Configure handler priorities.  */
;
    LDR     r1, =0x00000000                     ; Rsrv, UsgF, BusF, MemM
    STR     r1, [r0, #0xD18]                    ; Setup System Handlers 4-7 Priority Registers

    LDR     r1, =0xFF000000                     ; SVCl, Rsrv, Rsrv, Rsrv
    STR     r1, [r0, #0xD1C]                    ; Setup System Handlers 8-11 Priority Registers
                                                ; Note: SVC must be lowest priority, which is 0xFF

    LDR     r1, =0x40FF0000                     ; SysT, PnSV, Rsrv, DbgM
    STR     r1, [r0, #0xD20]                    ; Setup System Handlers 12-15 Priority Registers
                                                ; Note: PnSV must be lowest priority, which is 0xFF
;
;    /* Return to caller.  */
;
    BX      lr
;}
;/* Define shells for each of the unused vectors.  */
;
    EXPORT  __tx_BadHandler
__tx_BadHandler
    B   __tx_BadHandler


    EXPORT  __tx_SVCallHandler
__tx_SVCallHandler
    B       __tx_SVCallHandler


    EXPORT  __tx_IntHandler
__tx_IntHandler
; VOID InterruptHandler (VOID)
; {
    PUSH    {r0, lr}

;    /* Do interrupt handler work here */
;    /* .... */

    POP     {r0, lr}
    BX      LR
; }

    EXPORT  __tx_SysTickHandler
	EXPORT SysTick_Handler
__tx_SysTickHandler
SysTick_Handler
; VOID TimerInterruptHandler (VOID)
; {
;
    PUSH    {r0, lr}
    BL      _tx_timer_interrupt
    POP     {r0, lr}
    BX      LR
; }

    EXPORT  __tx_NMIHandler
__tx_NMIHandler
    B       __tx_NMIHandler

    EXPORT  __tx_DBGHandler
__tx_DBGHandler
    B       __tx_DBGHandler
    ALIGN
    LTORG
    END