diff options
| -rw-r--r-- | libc/sysdeps/linux/i386/Makefile | 12 | ||||
| -rw-r--r-- | libc/sysdeps/linux/i386/crt0.S | 123 |
2 files changed, 133 insertions, 2 deletions
diff --git a/libc/sysdeps/linux/i386/Makefile b/libc/sysdeps/linux/i386/Makefile index 9c487bfd1..a6b185c21 100644 --- a/libc/sysdeps/linux/i386/Makefile +++ b/libc/sysdeps/linux/i386/Makefile @@ -25,7 +25,10 @@ include $(TOPDIR)Rules.mak LIBC=$(TOPDIR)libc.a ASFLAGS=$(CFLAGS) -SSRC=_start.S longjmp.S setjmp.S #_start.S #clone.S +CRT0=crt0.S +CRT0_OBJ=$(patsubst %.S,%.o, $(CRT0)) + +SSRC=longjmp.S setjmp.S #_start.S #clone.S ifeq ($(UNIFIED_SYSCALL),true) SSRC += __uClibc_syscall.S endif @@ -37,13 +40,18 @@ COBJS=$(patsubst %.c,%.o, $(CSRC)) OBJS=$(SOBJS) $(COBJS) -all: $(OBJS) $(LIBC) +all: $(OBJS) $(CRT0_OBJ) $(LIBC) $(LIBC): ar-target ar-target: $(OBJS) $(AR) $(ARFLAGS) $(LIBC) $(OBJS) +$(CRT0_OBJ): %.o : %.S + $(CC) $(CFLAGS) -c $< -o $@ + $(STRIPTOOL) -x -R .note -R .comment $*.o + cp $*.o $(TOPDIR)/libcrt0.o + $(SOBJS): %.o : %.S $(CC) $(CFLAGS) -c $< -o $@ $(STRIPTOOL) -x -R .note -R .comment $*.o diff --git a/libc/sysdeps/linux/i386/crt0.S b/libc/sysdeps/linux/i386/crt0.S new file mode 100644 index 000000000..08e406cc6 --- /dev/null +++ b/libc/sysdeps/linux/i386/crt0.S @@ -0,0 +1,123 @@ +/* Copyright (C) 1991, 1992 Free Software Foundation, Inc. +This file is part of the GNU C Library. + +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. + +The GNU C Library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + + +/* If you don't know what is going on here, check out + http://linuxassembly.org/startup.html + For a description of the stack layout. + -John Beppu, and Erik Andersen +*/ + +.global __environ +.global __errno +.global _start +.global exit +.global main +.global __stdio_close_all +.global _void_void_null_func +.global _start_exit + +.text +_start: + /* First locate the start of the environment variables */ + popl %ecx /* Store argc into %ecx */ + movl %esp,%ebx /* Store argv into ebx */ + movl %esp,%eax /* Store argv into eax as well*/ + movl %ecx,%edx /* Stick argc into %edx so we can do some math in a sec */ + leal 4(%eax,%edx,4),%eax + + /* [ register layout ] + + sizeof(char*) == 4 + %ecx = argc ; 0(esp) + %ebx = argv ; 4(esp) + %eax = env ; argv + (argc * 4) + 4 + */ + + + /* Set up an invalid (NULL return address, NULL frame pointer) + callers stack frame so anybody unrolling the stack knows where + to stop */ + xorl %ebp,%ebp /* NULL */ + pushl %ebp /* callers %cs */ + pushl %ebp /* callers %eip (return address) */ + pushl %ebp /* callers %ebp (frame pointer) */ + movl %esp,%ebp /* mark callers stack frame as invalid */ + + /* Now set the environment, argc, and argv where the app can get to them */ + pushl %eax /* Environment pointer */ + pushl %ebx /* Argument pointer */ + pushl %ecx /* And the argument count */ + + /* Make sure we are not using iBCS2 personality. (i.e. force linux). */ + movl $136,%eax + sub %ebx,%ebx + int $0x80 + + /* set up __environ */ + movl 8(%esp),%eax + movl %eax,__environ + + /* Tell libc to initialize anything it needs to do */ + call __libc_init + /* call __malloc_init */ + call __init_stdio + + /* Ok, now run main() */ + call main + pushl %eax + call exit + + /* Just in case _exit fails... We use int $0x80 for __exit(). */ + popl %ebx + .align 4,0x90 +_start_exit: + movl $1,%eax + int $0x80 + jmp _start_exit + .align 4,0x90 +_void_void_null_func: + ret + +.weak __libc_init +__libc_init = _void_void_null_func + +/* +.weak __malloc_init +__malloc_init = _void_void_null_func +*/ + +.weak __init_stdio +__init_stdio = _void_void_null_func + +.weak __stdio_close_all +__stdio_close_all = _void_void_null_func + +.data +__environ: + .long 0 +.weak environ +.align 4 +environ = __environ + +.data +__errno: + .long 0 +.weak errno +.align 4 +errno = __errno |