move most of the _start operations to _start_c().
Signed-off-by: Zhangjin Wu <falcon@xxxxxxxxxxx>
---
tools/include/nolibc/i386/crt.h | 29 +++++++----------------------
1 file changed, 7 insertions(+), 22 deletions(-)
diff --git a/tools/include/nolibc/i386/crt.h b/tools/include/nolibc/i386/crt.h
index 0b88f7c887ae..87f31bc253a3 100644
--- a/tools/include/nolibc/i386/crt.h
+++ b/tools/include/nolibc/i386/crt.h
@@ -18,29 +18,14 @@ void __attribute__((weak, noreturn, optimize("omit-frame-pointer"))) __no_stack_
{
__asm__ volatile (
#ifdef _NOLIBC_STACKPROTECTOR
- "call __stack_chk_init\n" /* initialize stack protector */
+ "call __stack_chk_init\n" /* initialize stack protector */
#endif
- "pop %eax\n" /* argc (first arg, %eax) */
- "mov %esp, %ebx\n" /* argv[] (second arg, %ebx) */
- "lea 4(%ebx,%eax,4),%ecx\n" /* then a NULL then envp (third arg, %ecx) */
- "mov %ecx, environ\n" /* save environ */
- "xor %ebp, %ebp\n" /* zero the stack frame */
- "mov %ecx, %edx\n" /* search for auxv (follows NULL after last env) */
- "0:\n"
- "add $4, %edx\n" /* search for auxv using edx, it follows the */
- "cmp -4(%edx), %ebp\n" /* ... NULL after last env (ebp is zero here) */
- "jnz 0b\n"
- "mov %edx, _auxv\n" /* save it into _auxv */
- "and $-16, %esp\n" /* x86 ABI : esp must be 16-byte aligned before */
- "sub $4, %esp\n" /* the call instruction (args are aligned) */
- "push %ecx\n" /* push all registers on the stack so that we */
- "push %ebx\n" /* support both regparm and plain stack modes */
- "push %eax\n"
- "call main\n" /* main() returns the status code in %eax */
- "mov %eax, %ebx\n" /* retrieve exit code (32-bit int) */
- "movl $1, %eax\n" /* NR_exit == 1 */
- "int $0x80\n" /* exit now */
- "hlt\n" /* ensure it does not */
+ "xor %ebp, %ebp\n" /* zero the stack frame */
+ "mov %esp, %eax\n" /* save stack pointer to %eax, as arg1 of _start_c */
+ "and $-16, %esp\n" /* last pushed argument must be 16-byte aligned */
+ "push %eax\n" /* push arg1 on stack to support plain stack modes too */
+ "call _start_c\n" /* transfer to c runtime */
+ "hlt\n" /* ensure it does not return */
);
__builtin_unreachable();
}
--
2.25.1
