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openblt/Target/Source/ARM7_LPC2000/Crossworks/cstart.s

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/*****************************************************************************
* Copyright (c) 2001, 2002 Rowley Associates Limited. *
* *
* This file may be distributed under the terms of the License Agreement *
* provided with this software. *
* *
* THIS FILE IS PROVIDED AS IS WITH NO WARRANTY OF ANY KIND, INCLUDING THE *
* WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. *
*****************************************************************************/
/*****************************************************************************
* Preprocessor Definitions
* ------------------------
* APP_ENTRY_POINT
*
* Defines the application entry point function, if undefined this setting
* defaults to "main".
*
* INITIALIZE_STACKS
*
* If defined, the contents of the stacks will be initialized to a the
* value 0xCC.
*
* INITIALIZE_SECONDARY_SECTIONS
*
* If defined, the .text2, .data2 and .bss2 sections will be initialized.
*
* SUPERVISOR_START
*
* If defined, the application will start up in supervisor mode. If
* undefined the application will start up in system mode.
*
* FULL_LIBRARY
*
* If defined then
* - argc, argv are setup by the debug_getargs.
* - the exit symbol is defined and executes on return from main.
* - the exit symbol calls destructors, atexit functions and then debug_exit.
*
* If not defined then
* - argc and argv are zero.
* - the exit symbol is defined, executes on return from main and loops
*
*****************************************************************************/
.section .vectors, "ax"
.code 32
.align 0
.global _vectors
.global reset_handler
/*****************************************************************************
* Exception Vectors *
*****************************************************************************/
_vectors:
ldr pc, [pc, #reset_handler_address - . - 8] /* reset */
ldr pc, [pc, #undef_handler_address - . - 8] /* undefined instruction */
ldr pc, [pc, #undef_handler_address - . - 8] /* swi handler */
ldr pc, [pc, #pabort_handler_address - . - 8] /* abort prefetch */
ldr pc, [pc, #dabort_handler_address - . - 8] /* abort data */
.word 0xB9205F88 /* boot loader checksum */
ldr pc, [pc, #-0xFF0] /* irq handler */
ldr pc, [pc, #fiq_handler_address - . - 8] /* fiq handler */
reset_handler_address:
.word Reset_Handler
undef_handler_address:
.word undef_handler
pabort_handler_address:
.word pabort_handler
dabort_handler_address:
.word dabort_handler
fiq_handler_address:
.word fiq_handler
.section .init, "ax"
.code 32
.align 4
#ifndef APP_ENTRY_POINT
#define APP_ENTRY_POINT main
#endif
#ifndef ARGSSPACE
#define ARGSSPACE 128
#endif
.weak Reset_Handler
.global __start
.global __gccmain
.extern APP_ENTRY_POINT
.global exit
/************************************************************************************//**
** \brief Reset interrupt service routine. Configures the stack for each mode,
** disables the IRQ and FIQ interrupts, initializes RAM and jumps to
** function main.
** \return none.
**
****************************************************************************************/
Reset_Handler:
__start:
mrs r0, cpsr
bic r0, r0, #0x1F
/* Setup stacks */
orr r1, r0, #0x1B /* Undefined mode */
msr cpsr_cxsf, r1
ldr sp, =__stack_und_end__
#ifdef __ARM_EABI__
bic sp, sp, #0x7
#endif
orr r1, r0, #0x17 /* Abort mode */
msr cpsr_cxsf, r1
ldr sp, =__stack_abt_end__
#ifdef __ARM_EABI__
bic sp, sp, #0x7
#endif
orr r1, r0, #0x12 /* IRQ mode */
msr cpsr_cxsf, r1
ldr sp, =__stack_irq_end__
#ifdef __ARM_EABI__
bic sp, sp, #0x7
#endif
orr r1, r0, #0x11 /* FIQ mode */
msr cpsr_cxsf, r1
ldr sp, =__stack_fiq_end__
#ifdef __ARM_EABI__
bic sp, sp, #0x7
#endif
orr r1, r0, #0x13 /* Supervisor mode */
msr cpsr_cxsf, r1
ldr sp, =__stack_svc_end__
#ifdef __ARM_EABI__
bic sp, sp, #0x7
#endif
#ifdef SUPERVISOR_START
/* Start application in supervisor mode */
ldr r1, =__stack_end__ /* Setup user/system mode stack */
#ifdef __ARM_EABI__
bic r1, r1, #0x7
#endif
mov r2, sp
stmfd r2!, {r1}
ldmfd r2, {sp}^
#else
/* Start application in system mode */
orr r1, r0, #0x1F /* System mode */
msr cpsr_cxsf, r1
ldr sp, =__stack_end__
#ifdef __ARM_EABI__
bic sp, sp, #0x7
#endif
#endif
#ifdef INITIALIZE_STACKS
mov r2, #0xCC
ldr r0, =__stack_und_start__
ldr r1, =__stack_und_end__
bl memory_set
ldr r0, =__stack_abt_start__
ldr r1, =__stack_abt_end__
bl memory_set
ldr r0, =__stack_irq_start__
ldr r1, =__stack_irq_end__
bl memory_set
ldr r0, =__stack_fiq_start__
ldr r1, =__stack_fiq_end__
bl memory_set
ldr r0, =__stack_svc_start__
ldr r1, =__stack_svc_end__
bl memory_set
ldr r0, =__stack_start__
ldr r1, =__stack_end__
bl memory_set
#endif
/* Copy initialised memory sections into RAM (if necessary). */
ldr r0, =__data_load_start__
ldr r1, =__data_start__
ldr r2, =__data_end__
bl memory_copy
ldr r0, =__text_load_start__
ldr r1, =__text_start__
ldr r2, =__text_end__
bl memory_copy
ldr r0, =__fast_load_start__
ldr r1, =__fast_start__
ldr r2, =__fast_end__
bl memory_copy
ldr r0, =__ctors_load_start__
ldr r1, =__ctors_start__
ldr r2, =__ctors_end__
bl memory_copy
ldr r0, =__dtors_load_start__
ldr r1, =__dtors_start__
ldr r2, =__dtors_end__
bl memory_copy
ldr r0, =__rodata_load_start__
ldr r1, =__rodata_start__
ldr r2, =__rodata_end__
bl memory_copy
#ifdef INITIALIZE_SECONDARY_SECTIONS
ldr r0, =__data2_load_start__
ldr r1, =__data2_start__
ldr r2, =__data2_end__
bl memory_copy
ldr r0, =__text2_load_start__
ldr r1, =__text2_start__
ldr r2, =__text2_end__
bl memory_copy
ldr r0, =__rodata2_load_start__
ldr r1, =__rodata2_start__
ldr r2, =__rodata2_end__
bl memory_copy
#endif /* #ifdef INITIALIZE_SECONDARY_SECTIONS */
/* Zero the bss. */
ldr r0, =__bss_start__
ldr r1, =__bss_end__
mov r2, #0
bl memory_set
#ifdef INITIALIZE_SECONDARY_SECTIONS
ldr r0, =__bss2_start__
ldr r1, =__bss2_end__
mov r2, #0
bl memory_set
#endif /* #ifdef INITIALIZE_SECONDARY_SECTIONS */
/* Initialise the heap */
ldr r0, = __heap_start__
ldr r1, = __heap_end__
sub r1, r1, r0
cmp r1, #8
movge r2, #0
strge r2, [r0], #+4
strge r1, [r0]
/* Call constructors */
ldr r0, =__ctors_start__
ldr r1, =__ctors_end__
ctor_loop:
cmp r0, r1
beq ctor_end
ldr r2, [r0], #+4
stmfd sp!, {r0-r1}
mov lr, pc
#ifdef __ARM_ARCH_3__
mov pc, r2
#else
bx r2
#endif
ldmfd sp!, {r0-r1}
b ctor_loop
ctor_end:
.type start, function
start:
/* Jump to application entry point */
#ifdef FULL_LIBRARY
mov r0, #ARGSSPACE
ldr r1, =args
ldr r2, =debug_getargs
mov lr, pc
#ifdef __ARM_ARCH_3__
mov pc, r2
#else
bx r2
#endif
ldr r1, =args
#else
mov r0, #0
mov r1, #0
#endif
ldr r2, =APP_ENTRY_POINT
mov lr, pc
#ifdef __ARM_ARCH_3__
mov pc, r2
#else
bx r2
#endif
exit:
#ifdef FULL_LIBRARY
mov r5, r0 // save the exit parameter/return result
/* Call destructors */
ldr r0, =__dtors_start__
ldr r1, =__dtors_end__
dtor_loop:
cmp r0, r1
beq dtor_end
ldr r2, [r0], #+4
stmfd sp!, {r0-r1}
mov lr, pc
#ifdef __ARM_ARCH_3__
mov pc, r2
#else
bx r2
#endif
ldmfd sp!, {r0-r1}
b dtor_loop
dtor_end:
/* Call atexit functions */
ldr r2, =_execute_at_exit_fns
mov lr, pc
#ifdef __ARM_ARCH_3__
mov pc, r2
#else
bx r2
#endif
/* Call debug_exit with return result/exit parameter */
mov r0, r5
ldr r2, =debug_exit
mov lr, pc
#ifdef __ARM_ARCH_3__
mov pc, r2
#else
bx r2
#endif
#endif
/* Returned from application entry point/debug_exit, loop forever. */
exit_loop:
b exit_loop
memory_copy:
cmp r0, r1
moveq pc, lr
subs r2, r2, r1
moveq pc, lr
/* if either pointer or length is not word aligned then byte copy */
orr r3, r0, r1
orr r3, r3, r2
tst r3, #0x3
bne 2f
/* word copy */
1:
ldr r3, [r0], #+4
str r3, [r1], #+4
subs r2, r2, #4
bne 1b
mov pc, lr
/* byte copy */
2:
ldrb r3, [r0], #+1
strb r3, [r1], #+1
subs r2, r2, #1
bne 2b
mov pc, lr
memory_set:
cmp r0, r1
moveq pc, lr
strb r2, [r0], #1
b memory_set
.section .init, "ax"
.code 32
.align 0
/******************************************************************************
* *
* Default exception handlers *
* *
******************************************************************************/
/******************************************************************************
* *
* Default exception handlers *
* These are declared weak symbols so they can be redefined in user code. *
* *
******************************************************************************/
undef_handler:
b undef_handler
pabort_handler:
b pabort_handler
dabort_handler:
b dabort_handler
fiq_handler:
b fiq_handler
irq_handler:
b irq_handler
.weak undef_handler, pabort_handler, dabort_handler, fiq_handler, irq_handler
#ifdef FULL_LIBRARY
.bss
args:
.space ARGSSPACE
#endif
/* Setup attibutes of stack and heap sections so they don't take up unnecessary room in the elf file */
.section .stack, "wa", %nobits
.section .stack_abt, "wa", %nobits
.section .stack_irq, "wa", %nobits
.section .stack_fiq, "wa", %nobits
.section .stack_svc, "wa", %nobits
.section .stack_und, "wa", %nobits
.section .heap, "wa", %nobits
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