lh79524_sdk_runtime_ghs.as

SHARP_ARM720T_LH79524/5软件开发包_支持TFT_LCD_NAND_FLASH_ETH_USB

;***********************************************************************
; * $Workfile:   lh79524_sdk_runtime_ghs.as  $
; * $Revision:   1.0  $
; * $Author:   ZhangJ  $
; * $Date:   Oct 20 2004 09:10:28  $
; *
; * Project:  LH79520
; *
;
; * $Log:   //smaicnt2/pvcs/VM/sharpmcu/archives/sharpmcu/software/csps/lh79524/bsps/sdk79524/examples/common/lh79524_sdk_runtime_ghs.as-arc  $
;
;   Rev 1.0   Oct 20 2004 09:10:28   ZhangJ
;Initial revision.
;
;   Rev 1.0   Jul 09 2003 09:09:08   LiJ
;Initial revision.
; 
; *  COPYRIGHT (C) 2001  SHARP MICROELECTRONICS OF THE AMERICAS INC.
; *                         CAMAS, WA
;**********************************************************************/
;
; This code performs all the initialization required before
; branching to the main C application code.  It defines the
; ENTRY point, initializes the Stack Pointers for each mode,
; copies RO code and RW data from ROM to RAM and zero-initializes
; the ZI data areas used by the C code.
;

                AREA    LH79520_RUNTIME, CODE, READONLY

; Some standard definitions...

Mode_USR        EQU     0x10
Mode_FIQ        EQU     0x11
Mode_IRQ        EQU     0x12
Mode_SVC        EQU     0x13
Mode_ABT        EQU     0x17
Mode_UNDEF      EQU     0x1B
Mode_SYS        EQU     0x1F            ; only available on ARM Arch. v4

I_Bit           EQU     0x80
F_Bit           EQU     0x40

; Locations of our memory system
MEMORY_Limit    EQU     0x22000000              
; = Total 32M SDRAM on LPD board, end of memory is 0x01ff,ffff
; memory 0x20000000 to 0x21ffffff is mirror of memory
; 0x0 to 0x01ffffff
Stack_Limit     EQU     MEMORY_Limit - 0x10 
SVC_Stack       EQU     Stack_Limit             ; = 0x400 bytes
ABT_Stack       EQU     SVC_Stack - 0x400       ; = 0x200 bytes
UNDEF_Stack     EQU     ABT_Stack - 0x200       ; = 0x200 bytes
IRQ_Stack       EQU     UNDEF_Stack - 0x200     ; = 0x200 bytes
FIQ_Stack       EQU     IRQ_Stack - 0x200       ; = 0x200
USR_Stack       EQU     FIQ_Stack - 0x200       ; = XXX bytes          
                

        import  __ghsend_bss
        import  __ghsbegin_bss


        EXPORT  _runtime
_runtime


init_stacks
;/* --- Initialize stack pointer registers */
;/* Enter IRQ mode and set up the IRQ stack pointer */
        MOV     r0, #Mode_IRQ
        orr     r0,r0,#I_Bit
        orr     r0,r0,#F_Bit                    ;/* No interrupts */
        MSR     cpsr_c, r0
        LDR     sp, =IRQ_Stack

;/* Enter FIQ mode and set up the FIQ stack pointer */
        MOV     r0, #Mode_FIQ
        orr     r0,r0,#I_Bit
        orr     r0,r0,#F_Bit                    ;/* No interrupts */
        MSR     cpsr_c, r0
        LDR     sp, =FIQ_Stack

;/* Enter ABT mode and set up the ABT stack pointer */
        MOV     r0, #Mode_ABT
        orr     r0,r0,#I_Bit
        orr     r0,r0,#F_Bit                    ;/* No interrupts */
        MSR     cpsr_c, r0
        LDR     sp, =ABT_Stack

;/* Enter IRQ mode and set up the IRQ stack pointer */
        MOV     r0, #Mode_UNDEF
        orr     r0,r0,#I_Bit
        orr     r0,r0,#F_Bit                    ;/* No interrupts */
        MSR     cpsr_c, r0
        LDR     sp, =UNDEF_Stack

;/* Set up the SVC stack pointer last and return to SVC mode */
        MOV     r0, #Mode_SVC
        orr     r0,r0,#I_Bit
        orr     r0,r0,#F_Bit                    ;/* No interrupts */
        MSR     cpsr_c, r0
        LDR     sp, =SVC_Stack 


; Zero Initialize memory
        MOV     r3, #0
        LDR     r2, bssStart    ; base in r2
        LDR     r0, bssEnd
        SUBS    r0,r0,r2        ; length in r0
        CMP     r0, #0
        BEQ     F91
B90
        STR     r3, [r2], #4
        SUBS    r0, r0, #4
        BGT     B90
F91

; enable the Cache and Write buffer
        MOV     r1,#0x7C    ;enable cache, enable write buffer
        MCR     p15, 0, r1, c1, c0, 0

; --- Now we enter the main C application code
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
        IMPORT  c_entry

; DO THE REST OF THINGS IN C UNLESS IT IS NOT POSSIBLE

        BL      c_entry ; in C_main.c

; If above subroutine ever returns, just sit in an endless loop
here    B       here

bssEnd
    dcd __ghsend_bss
bssStart
    dcd __ghsbegin_bss


        END