?? cstartup.s
字號:
/*------------------------------------------------------------------------------
//*- 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 : Cstartup.s
//*- Object : Generic CStartup for KEIL and GCC No Use REMAP
//*- Compilation flag : None
//*-
//*- 1.0 18/Oct/04 JPP : Creation
//*- 1.1 21/Feb/05 JPP : Set Interrupt
//*- 1.1 01/Apr/05 JPP : save SPSR
//*-----------------------------------------------------------------------------*/
.equ IRQ_Stack_Size, 0x00000060
/* #include "AT91SAM7S64_inc.h" */
.equ AIC_IVR, (256)
.equ AIC_FVR, (260)
.equ AIC_EOICR, (304)
.equ AT91C_BASE_AIC, (0xFFFFF000)
#;------------------------------------------------------------------------------
#;- Section Definition
#;-----------------
#;- Section
#;- .internal_ram_top Top_Stack: used by the cstartup for vector initalisation
#;- management defined by ld and affect from ldscript
#;------------------------------------------------------------------------------
.section .internal_ram_top
.code 32
.align 0
.global Top_Stack
Top_Stack:
/*------------------------------------------------------------------------------
*- Area Definition
*------------------------------------------------------------------------------
* .text is used instead of .section .text so it works with arm-aout too. */
.section .reset
.text
.global _startup
.func _startup
_startup:
reset:
/*------------------------------------------------------------------------------
//*- Exception vectors
//*--------------------
//*- These vectors can be read at address 0 or at RAM address
//*- They ABSOLUTELY requires to be in relative addresssing mode in order to
//*- guarantee a valid jump. For the moment, all are just looping.
//*- If an exception occurs before remap, this would result in an infinite loop.
//*- To ensure if a exeption occurs before start application to infinite loop.
//*------------------------------------------------------------------------------*/
B InitReset /* 0x00 Reset handler */
undefvec:
B undefvec /* 0x04 Undefined Instruction */
swivec:
B swivec /* 0x08 Software Interrupt */
pabtvec:
B pabtvec /* 0x0C Prefetch Abort */
dabtvec:
B dabtvec /* 0x10 Data Abort */
rsvdvec:
B rsvdvec /* 0x14 reserved */
irqvec:
B IRQ_Handler_Entry /* 0x18 IRQ */
fiqvec: /* 0x1c FIQ */
/*------------------------------------------------------------------------------
//*- Function : FIQ_Handler_Entry
//*- Treatments : FIQ Controller Interrupt Handler.
//*- Called Functions : AIC_FVR[interrupt]
//*------------------------------------------------------------------------------*/
FIQ_Handler_Entry:
/*- Switch in SVC/User Mode to allow User Stack access for C code */
/* because the FIQ is not yet acknowledged*/
/*- Save and r0 in FIQ_Register */
mov r9,r0
ldr r0 , [r8, #AIC_FVR]
msr CPSR_c,#I_BIT | F_BIT | ARM_MODE_SVC
/*- Save scratch/used registers and LR in User Stack */
stmfd sp!, { r1-r3, r12, lr}
/*- Branch to the routine pointed by the AIC_FVR */
mov r14, pc
bx r0
/*- Restore scratch/used registers and LR from User Stack */
ldmia sp!, { r1-r3, r12, lr}
/*- Leave Interrupts disabled and switch back in FIQ mode */
msr CPSR_c, #I_BIT | F_BIT | ARM_MODE_FIQ
/*- Restore the R0 ARM_MODE_SVC register */
mov r0,r9
/*- Restore the Program Counter using the LR_fiq directly in the PC */
subs pc,lr,#4
.align 0
.RAM_TOP:
.word Top_Stack
InitReset:
/*------------------------------------------------------------------------------
/*- Low level Init (PMC, AIC, ? ....) by C function AT91F_LowLevelInit
/*------------------------------------------------------------------------------*/
.extern AT91F_LowLevelInit
/*- minumum C initialization */
/*- call AT91F_LowLevelInit( void) */
ldr r13,.RAM_TOP /* temporary stack in internal RAM */
/*--Call Low level init function in ABSOLUTE through the Interworking */
ldr r0,=AT91F_LowLevelInit
mov lr, pc
bx r0
/*------------------------------------------------------------------------------
//*- Stack Sizes Definition
//*------------------------
//*- Interrupt Stack requires 2 words x 8 priority level x 4 bytes when using
//*- the vectoring. This assume that the IRQ management.
//*- The Interrupt Stack must be adjusted depending on the interrupt handlers.
//*- Fast Interrupt not requires stack If in your application it required you must
//*- be definehere.
//*- The System stack size is not defined and is limited by the free internal
//*- SRAM.
//*------------------------------------------------------------------------------*/
/*------------------------------------------------------------------------------
//*- Top of Stack Definition
//*-------------------------
//*- Interrupt and Supervisor Stack are located at the top of internal memory in
//*- order to speed the exception handling context saving and restoring.
//*- ARM_MODE_SVC (Application, C) Stack is located at the top of the external memory.
//*------------------------------------------------------------------------------*/
.EQU IRQ_STACK_SIZE, (3*8*4)
.EQU ARM_MODE_FIQ, 0x11
.EQU ARM_MODE_IRQ, 0x12
.EQU ARM_MODE_SVC, 0x13
.EQU I_BIT, 0x80
.EQU F_BIT, 0x40
/*------------------------------------------------------------------------------
//*- Setup the stack for each mode
//*-------------------------------*/
mov r0,r13
/*- Set up Fast Interrupt Mode and set FIQ Mode Stack*/
msr CPSR_c, #ARM_MODE_FIQ | I_BIT | F_BIT
/*- Init the FIQ register*/
ldr r8, =AT91C_BASE_AIC
/*- Set up Interrupt Mode and set IRQ Mode Stack*/
msr CPSR_c, #ARM_MODE_IRQ | I_BIT | F_BIT
mov r13, r0 /* Init stack IRQ */
sub r0, r0, #IRQ_Stack_Size
/*- Set up Supervisor Mode and set Supervisor Mode Stack*/
msr CPSR_c, #ARM_MODE_SVC
mov r13, r0 /* Init stack Sup */
/*- Enable interrupt & Set up Supervisor Mode and set Supervisor Mode Stack*/
# Relocate .data section (Copy from ROM to RAM)
LDR R1, =_etext
LDR R2, =_data
LDR R3, =_edata
LoopRel: CMP R2, R3
LDRLO R0, [R1], #4
STRLO R0, [R2], #4
BLO LoopRel
# Clear .bss section (Zero init)
MOV R0, #0
LDR R1, =__bss_start__
LDR R2, =__bss_end__
LoopZI: CMP R1, R2
STRLO R0, [R1], #4
BLO LoopZI
ldr lr,=exit
ldr r0,=main
bx r0
.size _startup, . - _startup
.endfunc
/* "exit" dummy added by mthomas to avoid sbrk write read etc. needed
by the newlib default "exit" */
.global exit
.func exit
exit:
b .
.size exit, . - exit
.endfunc
/*------------------------------------------------------------------------------
//*- Manage exception
//*---------------
//*- This module The exception must be ensure in ARM mode
//*------------------------------------------------------------------------------
//*------------------------------------------------------------------------------
//*- Function : IRQ_Handler_Entry
//*- Treatments : IRQ Controller Interrupt Handler.
//*- Called Functions : AIC_IVR[interrupt]
//*------------------------------------------------------------------------------*/
.global IRQ_Handler_Entry
.func IRQ_Handler_Entry
IRQ_Handler_Entry:
/*- Manage Exception Entry */
/*- Adjust and save LR_irq in IRQ stack */
sub lr, lr, #4
stmfd sp!, {lr}
/*- Save SPSR need to be saved for nested interrupt */
mrs r14, SPSR
stmfd sp!, {r14}
/*- Save and r0 in IRQ stack */
stmfd sp!, {r0}
/*- Write in the IVR to support Protect Mode */
/*- No effect in Normal Mode */
/*- De-assert the NIRQ and clear the source in Protect Mode */
ldr r14, =AT91C_BASE_AIC
ldr r0 , [r14, #AIC_IVR]
str r14, [r14, #AIC_IVR]
/*- Enable Interrupt and Switch in Supervisor Mode */
msr CPSR_c, #ARM_MODE_SVC
/*- Save scratch/used registers and LR in User Stack */
stmfd sp!, { r1-r3, r12, r14}
/*- Branch to the routine pointed by the AIC_IVR */
mov r14, pc
bx r0
/*- Restore scratch/used registers and LR from User Stack*/
ldmia sp!, { r1-r3, r12, r14}
/*- Disable Interrupt and switch back in IRQ mode */
msr CPSR_c, #I_BIT | ARM_MODE_IRQ
/*- Mark the End of Interrupt on the AIC */
ldr r14, =AT91C_BASE_AIC
str r14, [r14, #AIC_EOICR]
/*- Restore SPSR_irq and r0 from IRQ stack */
ldmia sp!, {r0}
/*- Restore SPSR_irq and r0 from IRQ stack */
ldmia sp!, {r14}
msr SPSR_cxsf, r14
/*- Restore adjusted LR_irq from IRQ stack directly in the PC */
ldmia sp!, {pc}^
.size IRQ_Handler_Entry, . - IRQ_Handler_Entry
.endfunc
/*---------------------------------------------------------------
//* ?EXEPTION_VECTOR
//* This module is only linked if needed for closing files.
//*---------------------------------------------------------------*/
.global AT91F_Default_FIQ_handler
.func AT91F_Default_FIQ_handler
AT91F_Default_FIQ_handler:
b AT91F_Default_FIQ_handler
.size AT91F_Default_FIQ_handler, . - AT91F_Default_FIQ_handler
.endfunc
.global AT91F_Default_IRQ_handler
.func AT91F_Default_IRQ_handler
AT91F_Default_IRQ_handler:
b AT91F_Default_IRQ_handler
.size AT91F_Default_IRQ_handler, . - AT91F_Default_IRQ_handler
.endfunc
.global AT91F_Spurious_handler
.func AT91F_Spurious_handler
AT91F_Spurious_handler:
b AT91F_Spurious_handler
.size AT91F_Spurious_handler, . - AT91F_Spurious_handler
.endfunc
.end
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