/***************************************************************************** | |
* Copyright (c) 2009 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". | |
* | |
* USE_PROCESS_STACK | |
* | |
* If defined, thread mode will be configured to use the process stack if | |
* the size of the process stack is greater than zero bytes in length. | |
* | |
* INITIALIZE_STACK | |
* | |
* If defined, the contents of the stack will be initialized to a the | |
* value 0xCC. | |
* | |
* 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. | |
* - no exit symbol, code loops on return from main. | |
*****************************************************************************/ | |
#ifndef APP_ENTRY_POINT | |
#define APP_ENTRY_POINT main | |
#endif | |
#ifndef ARGSSPACE | |
#define ARGSSPACE 128 | |
#endif | |
.global _start | |
.syntax unified | |
.extern APP_ENTRY_POINT | |
#ifdef FULL_LIBRARY | |
.global exit | |
#endif | |
.section .init, "ax" | |
.code 16 | |
.align 2 | |
.thumb_func | |
_start: | |
#ifdef __RAM_BUILD | |
ldr r1, =__stack_end__ | |
mov sp, r1 | |
#endif | |
#ifdef INITIALIZE_STACK | |
mov r2, #0xCC | |
ldr r0, =__stack_start__ | |
#ifndef __RAM_BUILD | |
mov r1, sp | |
#endif | |
bl memory_set | |
#endif | |
#ifdef USE_PROCESS_STACK | |
/* Set up process stack if size > 0 */ | |
ldr r1, =__stack_process_end__ | |
ldr r0, =__stack_process_start__ | |
subs r2, r1, r0 | |
beq 1f | |
msr psp, r1 | |
mov r2, #2 | |
msr control, r2 | |
#ifdef INITIALIZE_STACK | |
mov r2, #0xCC | |
bl memory_set | |
#endif | |
1: | |
#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 | |
/* Zero the bss. */ | |
ldr r0, =__bss_start__ | |
ldr r1, =__bss_end__ | |
mov r2, #0 | |
bl memory_set | |
/* Initialise the heap */ | |
ldr r0, = __heap_start__ | |
ldr r1, = __heap_end__ | |
sub r1, r1, r0 | |
mov r2, #0 | |
str r2, [r0] | |
add r0, r0, #4 | |
str r1, [r0] | |
/* Call constructors */ | |
ldr r0, =__ctors_start__ | |
ldr r1, =__ctors_end__ | |
ctor_loop: | |
cmp r0, r1 | |
beq ctor_end | |
ldr r2, [r0] | |
add r0, #4 | |
push {r0-r1} | |
blx r2 | |
pop {r0-r1} | |
b ctor_loop | |
ctor_end: | |
/* Setup initial call frame */ | |
mov r0, #0 | |
mov lr, r0 | |
mov r12, sp | |
start: | |
/* Jump to application entry point */ | |
#ifdef FULL_LIBRARY | |
mov r0, #ARGSSPACE | |
ldr r1, =args | |
ldr r2, =debug_getargs | |
blx r2 | |
ldr r1, =args | |
#else | |
mov r0, #0 | |
mov r1, #0 | |
#endif | |
ldr r2, =APP_ENTRY_POINT | |
blx r2 | |
#ifdef FULL_LIBRARY | |
.thumb_func | |
exit: | |
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] | |
add r0, #4 | |
push {r0-r1} | |
blx r2 | |
pop {r0-r1} | |
b dtor_loop | |
dtor_end: | |
/* Call atexit functions */ | |
ldr r2, =_execute_at_exit_fns | |
blx r2 | |
/* Call debug_exit with return result/exit parameter */ | |
mov r0, r5 | |
ldr r2, =debug_exit | |
blx r2 | |
#endif | |
/* Returned from application entry point, loop forever. */ | |
exit_loop: | |
b exit_loop | |
memory_copy: | |
cmp r0, r1 | |
beq 2f | |
subs r2, r2, r1 | |
beq 2f | |
1: | |
ldrb r3, [r0] | |
add r0, r0, #1 | |
strb r3, [r1] | |
add r1, r1, #1 | |
subs r2, r2, #1 | |
bne 1b | |
2: | |
bx lr | |
memory_set: | |
cmp r0, r1 | |
beq 1f | |
strb r2, [r0] | |
add r0, r0, #1 | |
b memory_set | |
1: | |
bx lr | |
#ifdef FULL_LIBRARY | |
.bss | |
args: | |
.space ARGSSPACE | |
#endif | |