99 lines
1.8 KiB
ArmAsm
99 lines
1.8 KiB
ArmAsm
|
|
|
|
.file "crt0.S"
|
|
|
|
#define XGLUE(a,b) a##b
|
|
#define GLUE(a,b) XGLUE(a,b)
|
|
|
|
#ifdef __USER_LABEL_PREFIX__
|
|
#define SYM_NAME( name ) GLUE (__USER_LABEL_PREFIX__, name)
|
|
#else
|
|
#error __USER_LABEL_PREFIX is not defined
|
|
#endif
|
|
|
|
.text
|
|
/*
|
|
* Setup the assembly entry point.
|
|
*/
|
|
.code 32
|
|
.globl SYM_NAME(start)
|
|
.globl SYM_NAME(_start)
|
|
SYM_NAME(start):
|
|
SYM_NAME(_start):
|
|
mov fp, #0 /* Null frame pointer */
|
|
mov r7, #0 /* Null frame pointer for Thumb */
|
|
|
|
/* enable interrupts for gdb debugging */
|
|
mrs r0, cpsr
|
|
bic r0, r0, #0xC0
|
|
msr cpsr, r0
|
|
|
|
mov a2, #0 /* Second arg: fill value */
|
|
ldr a1, .LC1 /* First arg: start of memory block */
|
|
ldr a3, .LC2
|
|
sub a3, a3, a1 /* Third arg: length of block */
|
|
|
|
#ifdef __thumb__ /* Enter Thumb mode.... */
|
|
add a4, pc, #1 /* Get the address of the Thumb block */
|
|
bx a4 /* Go there and start Thumb decoding */
|
|
|
|
.code 16
|
|
.global __change_mode
|
|
.thumb_func
|
|
__change_mode:
|
|
#endif
|
|
|
|
bl SYM_NAME(memset)
|
|
|
|
bl SYM_NAME(__get_memtop)
|
|
sub r0, r0, #32
|
|
mov sp, r0
|
|
|
|
#ifdef __USES_INITFINI__
|
|
/* Some arm/elf targets use the .init and .fini sections
|
|
to create constructors and destructors, and for these
|
|
targets we need to call the _init function and arrange
|
|
for _fini to be called at program exit. */
|
|
ldr r0, .Lfini
|
|
bl SYM_NAME (atexit)
|
|
bl SYM_NAME (_init)
|
|
#endif
|
|
|
|
mov a1, #0
|
|
ldr a2, .LC3
|
|
mov a3, a2
|
|
bl SYM_NAME(main)
|
|
1: bl SYM_NAME(exit)
|
|
b 1b
|
|
.align 2
|
|
.LC1:
|
|
.word __bss_start__
|
|
.LC2:
|
|
.word __bss_end__
|
|
.LC3:
|
|
.word 0
|
|
#ifdef __USES_INITFINI__
|
|
.Lfini:
|
|
.word SYM_NAME(_fini)
|
|
#endif
|
|
|
|
#if 0
|
|
#ifdef __thumb__
|
|
.code 16
|
|
#endif
|
|
.global SYM_NAME(__syscall)
|
|
#ifdef __thumb__
|
|
.thumb_func
|
|
#else
|
|
.align 4
|
|
#endif
|
|
SYM_NAME(__syscall):
|
|
mov r12, lr
|
|
#ifdef __thumb__
|
|
swi 0x18
|
|
#else
|
|
swi 0x180001
|
|
#endif
|
|
mov pc, r12
|
|
#endif
|