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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. *
*****************************************************************************/
.section .init, "ax"
.code 32
.align 0
.weak _start
.global __start
.global __gccmain
.extern main
.extern exit
/*****************************************************************************
* Function : _start *
* Description : Main entry point and startup code for C system. *
*****************************************************************************/
_start:
__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__
orr r1, r0, #0x17 /* Abort mode */
msr cpsr_cxsf, r1
ldr sp, =__stack_abt_end__
orr r1, r0, #0x12 /* IRQ mode */
msr cpsr_cxsf, r1
ldr sp, =__stack_irq_end__
orr r1, r0, #0x11 /* FIQ mode */
msr cpsr_cxsf, r1
ldr sp, =__stack_fiq_end__
orr r1, r0, #0x13 /* Supervisor mode */
msr cpsr_cxsf, r1
ldr sp, =__stack_svc_end__
#ifdef SUPERVISOR_START
/* Start application in supervisor mode */
ldr r1, =__stack_end__ /* Setup user/system mode stack */
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__
#endif
/* Copy from initialised data section to data section (if necessary). */
ldr r0, =__data_load_start__
ldr r1, =__data_start__
cmp r0, r1
beq copy_data_end
ldr r2, =__data_end__
subs r2, r2, r1
beq copy_data_end
copy_data_loop:
ldrb r3, [r0], #+1
strb r3, [r1], #+1
subs r2, r2, #1
bne copy_data_loop
copy_data_end:
/* Copy from initialised text section to text section (if necessary). */
ldr r0, =__text_load_start__
ldr r1, =__text_start__
cmp r0, r1
beq copy_text_end
ldr r2, =__text_end__
subs r2, r2, r1
beq copy_text_end
copy_text_loop:
ldrb r3, [r0], #+1
strb r3, [r1], #+1
subs r2, r2, #1
bne copy_text_loop
copy_text_end:
/* Copy from initialised fast_text section to fast_text section (if necessary). */
ldr r0, =__fast_load_start__
ldr r1, =__fast_start__
cmp r0, r1
beq copy_fast_end
ldr r2, =__fast_end__
subs r2, r2, r1
beq copy_fast_end
copy_fast_loop:
ldrb r3, [r0], #+1
strb r3, [r1], #+1
subs r2, r2, #1
bne copy_fast_loop
copy_fast_end:
/* Zero the bss. */
ldr r0, =__bss_start__
ldr r1, =__bss_end__
mov r2, #0
zero_bss_loop:
cmp r0, r1
beq zero_bss_end
strb r2, [r0], #+1
b zero_bss_loop
zero_bss_end:
#ifdef CHECK
/* Check data */
ldr r0, =__data_load_start__
ldr r1, =__data_start__
cmp r0, r1
beq check_data_end
ldr r2, =__data_end__
subs r2, r2, r1
beq check_data_end
check_data_loop:
ldrb r3, [r0], #+1
ldrb r4, [r1], #+1
cmp r3, r4
bne data_error_loop
subs r2, r2, #1
bne check_data_loop
check_data_end:
/* Check text */
ldr r0, =__text_load_start__
ldr r1, =__text_start__
cmp r0, r1
beq check_text_end
ldr r2, =__text_end__
subs r2, r2, r1
beq check_text_end
check_text_loop:
ldrb r3, [r0], #+1
ldrb r4, [r1], #+1
cmp r3, r4
bne text_error_loop
subs r2, r2, #1
bne check_text_loop
check_text_end:
/* Check fast */
ldr r0, =__fast_load_start__
ldr r1, =__fast_start__
cmp r0, r1
beq check_fast_end
ldr r2, =__fast_end__
subs r2, r2, r1
beq check_fast_end
check_fast_loop:
ldrb r3, [r0], #+1
ldrb r4, [r1], #+1
cmp r3, r4
bne fast_error_loop
subs r2, r2, #1
bne check_fast_loop
check_fast_end:
/* Check bss */
ldr r0, =__bss_start__
ldr r1, =__bss_end__
mov r2, #0
check_bss_loop:
cmp r0, r1
beq check_bss_end
ldrb r2, [r0], #+1
cmp r2, #0
bne bss_error_loop
b check_bss_loop
check_bss_end:
#endif
/* Initialise the heap */
ldr r0, = __heap_start__
ldr r1, = __heap_end__
sub r1, r1, r0 /* r1 = r1-r0 */
mov r2, #0
str r2, [r0], #+4 /* *r0++ = 0 */
str r1, [r0] /* *r0 = __heap_end__ - __heap_start__ */
/* 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
mov pc, r2
ldmfd sp!, {r0-r1}
b ctor_loop
ctor_end:
/* Setup initial call frame */
mov lr, #4
mov r12, sp
stmfd sp!, {r11-r12, lr-pc}
sub r11, r12, #0x00000004
start:
/* Jump to main entry point */
mov r0, #0
mov r1, #0
ldr r2, =main
mov lr, pc
#ifdef __ARM_ARCH_3__
mov pc, r2
#else
bx r2
#endif
/* 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
mov pc, r2
ldmfd sp!, {r0-r1}
b dtor_loop
dtor_end:
/* Return from main, loop forever. */
exit_loop:
b exit_loop
#ifdef CHECK
data_error_loop:
b data_error_loop
text_error_loop:
b text_error_loop
fast_error_loop:
b fast_error_loop
bss_error_loop:
b bss_error_loop
#endif
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