请问下lpc2xx的.s文件里面，用户模式堆栈大小怎么理解？
本帖最后由 hbchf 于 2013-12-4 22:31 编辑;/*****************************************************************************
;* startup.s: startup file for NXP LPC230x Family Microprocessors
;*
;* Copyright(C) 2006, NXP Semiconductor
;* All rights reserved.
;*
;* History
;* 2006.09.01ver 1.00 Prelimnary version, first Release
;*
;*****************************************************************************/
PRESERVE8
;/*
; *The STARTUP.S code is executed after CPU Reset. This file may be
; *translated with the following SET symbols. In uVision these SET
; *symbols are entered under Options - ASM - Define.
; *
; *REMAP: when set the startup code initializes the register MEMMAP
; *which overwrites the settings of the CPU configuration pins. The
; *startup and interrupt vectors are remapped from:
; * 0x00000000default setting (not remapped)
; * 0x40000000when RAM_MODE is used
; *
; *RAM_MODE: when set the device is configured for code execution
; *from on-chip RAM starting at address 0x40000000.
; */
; Standard definitions of Mode bits and Interrupt (I & F) flags in PSRs
Mode_USR EQU 0x10
Mode_FIQ EQU 0x11
Mode_IRQ EQU 0x12
Mode_SVC EQU 0x13
Mode_ABT EQU 0x17
Mode_UND EQU 0x1B
Mode_SYS EQU 0x1F
I_Bit EQU 0x80 ; when I bit is set, IRQ is disabled
F_Bit EQU 0x40 ; when F bit is set, FIQ is disabled
;// <h> Stack Configuration (Stack Sizes in Bytes)
;// <o0> Undefined Mode <0x0-0xFFFFFFFF:8>
;// <o1> Supervisor Mode <0x0-0xFFFFFFFF:8>
;// <o2> Abort Mode <0x0-0xFFFFFFFF:8>
;// <o3> Fast Interrupt Mode <0x0-0xFFFFFFFF:8>
;// <o4> Interrupt Mode <0x0-0xFFFFFFFF:8>
;// <o5> User/System Mode <0x0-0xFFFFFFFF:8>
;// </h>
UND_Stack_SizeEQU 0x00000000
SVC_Stack_SizeEQU 0x00000100
ABT_Stack_SizeEQU 0x00000000
FIQ_Stack_SizeEQU 0x00000000
IRQ_Stack_SizeEQU 0x00000100
USR_Stack_SizeEQU 0x00002000 ；
Stack_Size EQU (UND_Stack_Size + SVC_Stack_Size + ABT_Stack_Size + \
FIQ_Stack_Size + IRQ_Stack_Size + USR_Stack_Size)
AREA STACK, NOINIT, READWRITE, ALIGN=3
Stack_Mem SPACE Stack_Size
Stack_Top EQU Stack_Mem + Stack_Size
;// <h> Heap Configuration
;// <o>Heap Size (in Bytes) <0x0-0xFFFFFFFF>
;// </h>
Heap_Size EQU 0x00000000
AREA HEAP, NOINIT, READWRITE, ALIGN=3
Heap_Mem SPACE Heap_Size
; Area Definition and Entry Point
;Startup Code must be linked first at Address at which it expects to run.
AREA RESET, CODE, READONLY
ARM
; Exception Vectors
;Mapped to Address 0.
;Absolute addressing mode must be used.
;Dummy Handlers are implemented as infinite loops which can be modified.
Vectors LDR PC, Reset_Addr
LDR PC, Undef_Addr
LDR PC, SWI_Addr
LDR PC, PAbt_Addr
LDR PC, DAbt_Addr
NOP ; Reserved Vector
; LDR PC, IRQ_Addr
LDR PC, ; Vector from VicVectAddr
LDR PC, FIQ_Addr
Reset_Addr DCD Reset_Handler
Undef_Addr DCD Undef_Handler
SWI_Addr DCD SWI_Handler
PAbt_Addr DCD PAbt_Handler
DAbt_Addr DCD DAbt_Handler
DCD 0xB9206E28 ; Reserved Address
IRQ_Addr DCD IRQ_Handler
FIQ_Addr DCD FIQ_Handler
Undef_Handler B Undef_Handler
SWI_Handler B SWI_Handler
PAbt_Handler B PAbt_Handler
DAbt_Handler B DAbt_Handler
IRQ_Handler B IRQ_Handler
FIQ_Handler B FIQ_Handler
; Reset Handler
EXPORTReset_Handler
Reset_Handler
; Setup Stack for each mode
LDR R0, =Stack_Top
;Enter Undefined Instruction Mode and set its Stack Pointer
MSR CPSR_c, #Mode_UND:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #UND_Stack_Size
;Enter Abort Mode and set its Stack Pointer
MSR CPSR_c, #Mode_ABT:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #ABT_Stack_Size
;Enter FIQ Mode and set its Stack Pointer
MSR CPSR_c, #Mode_FIQ:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #FIQ_Stack_Size
;Enter IRQ Mode and set its Stack Pointer
MSR CPSR_c, #Mode_IRQ:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #IRQ_Stack_Size
;Enter Supervisor Mode and set its Stack Pointer
MSR CPSR_c, #Mode_SVC:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #SVC_Stack_Size
;Enter User Mode and set its Stack Pointer
MSR CPSR_c, #Mode_USR
MOV SP, R0
SUB SL, SP, #USR_Stack_Size
MOV R0, #0x40000000 ;RAM区首地址
LDR R1, =Vectors ;向量表首地址#下面一段程序是把从0x00000000开始的64个字节（FLASH中的中断向量表和地址表）搬移到以#0x40000000为首地址的RAM区中
LDMIA R1!, {R2-R9} ;把以为首地址的32个字节数据装载到R2-R9中
STMIA R0!, {R2-R9} ;把R2-R9中的数据存入以为首地址的单元中
LDMIA R1!, {R2-R9} ;把以为首地址的32个字节数据装载到R2-R9中
STMIA R0!, {R2-R9} ;把R2-R9中的数据存入以为首地址的单元中
IMPORT TargetResetInit
BL TargetResetInit
; Enter the C code
IMPORT__main
LDR R0, =__main
BX R0
; User Initial Stack & Heap
AREA |.text|, CODE, READONLY
IMPORT__use_two_region_memory
EXPORT__user_initial_stackheap
__user_initial_stackheap
LDR R0, =Heap_Mem
LDR R1, =(Stack_Mem + USR_Stack_Size)
LDR R2, = (Heap_Mem + Heap_Size)
LDR R3, = Stack_Mem
BX LR
END
上面第57行，USR_Stack_SizeEQU 0x00002000 这个堆栈在实际应用中是什么原理？
我理解是就是程序在ram上创建了个堆栈结构的数据结构，用于存储程序里面的所有变量。比如程序每执行一个子函数时，为局部变量的空间申请提供空间。是这样理解的吗？希望哪位高手能够深入的替我分析下，谢谢了！
页:
[1]