in_reset.s

uC/OS 使用gcc进行开发的例子,可以参考一下

/*
@ ------------------------------------------------------------------------------
@ -    ATMEL Microcontroller Software Support  -   ROUSSET -
@ ------------------------------------------------------------------------------
@  The software is delivered "AS IS" without warranty or condition of any
@  kind, either express, implied or statutory. This includes without
@  limitation any warranty or condition with respect to merchantability or
@  fitness for any particular purpose, or against the infringements of
@  intellectual property rights of others.
@ -----------------------------------------------------------------------------
@ - File source          : in_reset.s
@ - Object               : Boot of AT91EB01/DB01
@ - Translator           : ARM Software Development Toolkit V2.11a
@ -
@ - Exported Resources   : __main - InitResetStacks
@ - Imported Resources   : MainApplication - InitTableEBI - InitTableStack
@ -
@ - 1.0 15/09/98 JLV     : Creation
@ - 2.0 21/10/98 JCZ     : Clean up.
@ - 2.1 16/03/99 JCZ     : SDT V2.5
@ -                      : Remove warning concerning CPSR field specifier.
@ -                      : Reserve stack space on top of memory for ICE Debug.
@ ------------------------------------------------------------------------------

                AREA        IN_RESET, CODE, READONLY, INTERWORK

@  -------------------------- List of Included Files ---------------------------

@                 INCLUDE     Include/arm.inc
@ -------------------------------
@ - ARM Core Mode and Status Bits
@ -------------------------------
*/

	ARM_MODE_USER = 0x10
	ARM_MODE_FIQ 	= 0x11
	ARM_MODE_IRQ	= 0x12
	ARM_MODE_SVC	= 0x13
	ARM_MODE_ABORT= 0x17
	ARM_MODE_UNDEF= 0x1B
	ARM_MODE_SYS	= 0x1F

	I_BIT			= 0x80
	F_BIT			= 0x40
	T_BIT			= 0x20

/*
@                 INCLUDE     Include/int_mem.inc
@ ------------------------------
@ - AT91 Internal RAM Definition
@ ------------------------------
*/

	RAM_BASE            =     0x00000000
	RAM_SIZE            =     4096
	RAM_LIMIT           =     RAM_BASE + RAM_SIZE

/*
@                 INCLUDE     Include/aic.inc
*/

	AIC_BASE            =     0xFFFFF000

/*
@ -----------------------------------------
@ - Advanced Interrupt Controller Structure
@ -----------------------------------------
*/

AIC_SMR		= 0         @  Source Mode Register
AIC_SVR 	= AIC_SMR + 32*4        @  Source Vector Register
AIC_IVR 	= AIC_SVR + 32*4           @  Interrupt Vector Register
AIC_FVR 	= AIC_IVR + 4           @  Fast Interrupt Vector Register
AIC_ISR 	= AIC_FVR + 4           @  Interrupt Status Register
AIC_IPR 	= AIC_ISR + 4           @  Interrupt Pending Register
AIC_IMR 	= AIC_IPR + 4           @  Interrupt Mask Register
AIC_CISR	= AIC_IMR + 4          @  Core Interrupt Status Register
AIC_IECR	= AIC_CISR + 3*4           @  Interrupt Enable Command Register
AIC_IDCR	= AIC_IECR + 4           @  Interrupt Disable Command Register
AIC_ICCR	= AIC_IDCR + 4           @  Interrupt Clear Command Register
AIC_ISCR	= AIC_ICCR + 4           @  Interrupt Set Command Register
AIC_EOICR	= AIC_ISCR + 4           @  End Of Interrupt Command Register

US0IRQ              =     2

/*
@  ------------------------ List of constants and types ------------------------
@  None

@  ------------------------ List of Imported resources -------------------------
*/

                .global      InitMainSram

/*
@                 .global      InitTableStack

@    IF  :DEF:AT91_DEBUG_NONE
@                 .global      InitTableEBI
*/

                .global      MainApplication

/*
                .global      |Image$$RO$$Limit|      @  End of ROM code (=start of ROM data)
                .global      |Image$$RW$$Base|       @  Base of RAM to initialise
                .global      |Image$$ZI$$Base|       @  Base and limit of area
                .global      |Image$$ZI$$Limit|      @  to zero initialise
@    ENDIF

@  ------------------------ List of Internal resources -------------------------
@  None

@  ------------------------ List of Exported resources -------------------------

@    IF  :DEF:AT91_DEBUG_NONE

@ - Define the entry point
@               ENTRY

@ ------------------------------------------------------------------------------
@ - Function             : boot
@ - Treatments           : AT91 boot code
@ - Input Parameters     : None
@ - Output Parameters    : None
@ - Registers lost       : None
@ - Called Functions     : MainApplication
@ - Called Macros        : None
@ ------------------------------------------------------------------------------

@ - Define "__main" to ensure that C runtime system is not linked
*/
		.global	_start
                .global _main
_start:
_main:
	b	InitReset
undefvec:
	b	undefvec
swivec:
	b	swivec
pabtvec:
	b	pabtvec
dabtvec:
	b	dabtvec
rsvdvec:
	b	rsvdvec
irqvec:
	ldr	pc, [pc, #-0xf20]
fiqvec:
	ldr	pc, [pc, #-0xf20]

InitReset:
/*
@ - | Initialise the Memory Controller
@ - | ---------------------------------
@ - | Copy the Image of the Memory Controller
*/
                ldr         r10, PtInitTableEBI     @  get the address of the chip select register image

/* @ - | If pc > 0x100000 */
                movs        r0, pc, LSR #20
/* @ - | | Mask the 12 highest bits of the address */
                moveq       r10, r10, LSL #12
                moveq       r10, r10, LSR #12
/* @ - | EndIf */

/* @ - | Load the address where to jump */
                ldr         r12, PtInitRemap        @  get the real jump address ( after remap )

/* @ - | Copy Chip Select Register Image to Memory Controller and command remap */
                ldmia       r10!, {r0-r9,r11}       @  load the complete image and the EBI base
                stmia       r11!, {r0-r9}           @  store the complete image with the remap command

/* @ - | Jump to ROM at its new address */
                mov         pc, r12                 @  jump and break the pipeline

PtInitTableEBI:
                .word         InitTableEBI            @  Table for EBI initialization
PtInitRemap:
                .word         InitRemap               @  address where to jump after REMAP
PtInitVector:
                .word         _main                  @  Table for vector initialization


InitRemap:
/*
@ - | Setup Exception Vectors
@ - | -----------------------
@ - | Copy the hard exception vectors
*/
                mov         r8, #0                  @  @ of the hard vector
                ldr         r9, PtInitVector        @  @ where to read values
                ldmia       r9!, {r0-r7}            @  read the vectors
                stmia       r8!, {r0-r7}            @  store them

/* @ - | Set up the SVC mode and stack pointer on the top of the internal RAM */

                mov         r0, #ARM_MODE_SVC | I_BIT | F_BIT @  No interrupts
                msr         cpsr, r0
                ldr         r13, =RAM_LIMIT

/* @ - | Initialize the Stacks */
                bl          InitResetStacks

/* @ - | Initialise memory required by C code 
                ldr         r0, =|Image$$RO$$Limit| @  Get pointer to ROM data
                ldr         r1, =|Image$$RW$$Base|  @  and RAM copy
                ldr         r3, =|Image$$ZI$$Base|  @  Zero init base => top of initialised data
                cmp         r0, r1                  @  Check that they are different
                beq         NoRW
LoopRw          cmp         r1, r3                  @  Copy init data
                ldrcc       r2, [r0], #4
                strcc       r2, [r1], #4
                bcc         LoopRw
NoRW            ldr         r1, =|Image$$ZI$$Limit| @  Top of zero init segment
                mov         r2, #0
LoopZI          cmp         r3, r1                  @  Zero init
                strcc       r2, [r3], #4
                bcc         LoopZI

@ - | Branch on C code Main function
*/
                ldr         r0, =MainApplication
                mov         lr, pc
                bx          r0

/* @ - | Loop for ever */
InitEnd:
                b           InitEnd
/* @    ENDIF 
@ ------------------------------------------------------------------------------
@ - Function             : InitResetStacks
@ - Treatments           : AT91 boot code
@ -                        Must be call in Supervisor mode
@ - Input Parameters     : None
@ - Output Parameters    :
@ -      <AdFiq> = address of FIQ treatment which initialize the stack
@ - Registers lost       : None
@ - Called Functions     : None
@ - Called Macros        : None
@ ------------------------------------------------------------------------------
*/
            .global      InitResetStacks

InitResetStacks:
                ldr         r1, =AIC_BASE
/*
    IF  :DEF:AT91_DEBUG_ANGEL
@ - Disable all interrupt unless USART used by Angel
                mvn         r0, #(1:SHL:US0IRQ)
    ELSE
@ - Disable all interrupt
*/
                mvn         r0, #0
/*    ENDIF */
                str         r0, [r1, #AIC_IDCR]

/* @ - Perform 8 End Of Interrupt Command to make sure AIC will not lock out nIRQ */
                mov         r0, #8
LoopAic:
                str         r1, [r1, #AIC_EOICR]
                subs        r0, r0, #1
                bhi         LoopAic
/*
    IF  :DEF:AT91_DEBUG_ICE
@ - | -- Set IRQ and FIQ interrupt vectors