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authorMike Frysinger <vapier@gentoo.org>2005-02-15 01:42:47 +0000
committerMike Frysinger <vapier@gentoo.org>2005-02-15 01:42:47 +0000
commit1271f242c654c5a5a4d64bf599e73fada417f62e (patch)
tree1cc79930419d1a9fc64968412da321c4f5926921 /libc
parentde796c492662911dd28b5c687525cfcb208573cd (diff)
some incomplete asm source for x86_64
Diffstat (limited to 'libc')
-rw-r--r--libc/sysdeps/linux/x86_64/crt0.S164
-rw-r--r--libc/sysdeps/linux/x86_64/crti.S14
2 files changed, 178 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/x86_64/crt0.S b/libc/sysdeps/linux/x86_64/crt0.S
new file mode 100644
index 000000000..82dd9a9df
--- /dev/null
+++ b/libc/sysdeps/linux/x86_64/crt0.S
@@ -0,0 +1,164 @@
+/* Startup code compliant to the ELF x86-64 ABI.
+ Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Andreas Jaeger <aj@suse.de>, 2001.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ In addition to the permissions in the GNU Lesser General Public
+ License, the Free Software Foundation gives you unlimited
+ permission to link the compiled version of this file with other
+ programs, and to distribute those programs without any restriction
+ coming from the use of this file. (The GNU Lesser General Public
+ License restrictions do apply in other respects; for example, they
+ cover modification of the file, and distribution when not linked
+ into another program.)
+
+ Note that people who make modified versions of this file are not
+ obligated to grant this special exception for their modified
+ versions; it is their choice whether to do so. The GNU Lesser
+ General Public License gives permission to release a modified
+ version without this exception; this exception also makes it
+ possible to release a modified version which carries forward this
+ exception.
+
+ 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+/* Originally based on glibc's sysdeps/x86_64/elf/start.S */
+
+/* This is the canonical entry point, usually the first thing in the text
+ segment. The SVR4/i386 ABI (pages 3-31, 3-32) says that when the entry
+ point runs, most registers' values are unspecified, except for:
+
+ %rdx Contains a function pointer to be registered with `atexit'.
+ This is how the dynamic linker arranges to have DT_FINI
+ functions called for shared libraries that have been loaded
+ before this code runs.
+
+ %rsp The stack contains the arguments and environment:
+ 0(%rsp) argc
+ 8(%rsp) argv[0]
+ ...
+ (8*argc)(%rsp) NULL
+ (8*(argc+1))(%rsp) envp[0]
+ ...
+ NULL
+*/
+
+#include <features.h>
+
+.text
+ .global _start
+ .type _start,%function
+#if defined L_crt0 || defined L_Scrt0 || ! defined __UCLIBC_CTOR_DTOR__
+ .type __uClibc_main,%function
+#else
+ .weak _init
+ .weak _fini
+ .type __uClibc_start_main,%function
+#endif
+/* Stick in a dummy reference to main(), so that if an application
+ * is linking when the main() function is in a static library (.a)
+ * we can be sure that main() actually gets linked in */
+ .type main,%function
+
+_start:
+ /* Clear the frame pointer. The ABI suggests this be done, to mark
+ the outermost frame obviously. */
+ xorq %rbp, %rbp
+
+ /* Extract the arguments as encoded on the stack and set up
+ the arguments for __libc_start_main (int (*main) (int, char **, char **),
+ int argc, char *argv,
+ void (*init) (void), void (*fini) (void),
+ void (*rtld_fini) (void), void *stack_end).
+ The arguments are passed via registers and on the stack:
+ main: %rdi
+ argc: %rsi
+ argv: %rdx
+ init: %rcx
+ fini: %r8
+ rtld_fini: %r9
+ stack_end: stack. */
+
+ movq %rdx, %r9 /* Address of the shared library termination function. */
+ popq %rsi /* Pop the argument count. */
+ movq %rsp, %rdx /* argv starts just at the current stack top. */
+ movq %rsi, %rbx /* now we calc envp ... envp = argc */
+ shl $0x3, %rbx /* envp *= 8 */
+ addq %rdx, %rbx /* envp += argv */
+ /* Align the stack to a 16 byte boundary to follow the ABI. */
+ andq $~15, %rsp
+
+ pushq %rax /* Push garbage because we push 8 more bytes. */
+
+ /* Provide the highest stack address to the user code (for stacks
+ which grow downwards). */
+ pushq %rsp
+
+/**************
+ * START TODO */
+#if defined L_Scrt0 || defined L_Scrt1
+ call .L0
+.L0:
+ popq %rbx
+ addq $_GLOBAL_OFFSET_TABLE_+[.-.L0],%rbx
+#endif
+
+#if (defined L_crt1 || defined L_Scrt1) && defined __UCLIBC_CTOR_DTOR__
+ /* Push .init and .fini arguments to __uClibc_start_main() on the stack */
+#ifdef L_Scrt1
+ pushl _fini@GOT(%rip)
+ pushl _init@GOT(%rip)
+#else
+ pushl $_fini
+ pushl $_init
+#endif
+
+ /* Push envp, argc, and argc arguments to __uClibc_start_main() on the stack */
+ pushq %rbx /* Environment pointer */
+ pushq %rdx /* Argument pointer */
+ pushq %rsi /* And the argument count */
+
+ /* Ok, now run uClibc's main() -- shouldn't return */
+#ifdef L_Scrt1
+ call *__uClibc_start_main@GOT(%rip)
+#else
+ call __uClibc_start_main
+#endif
+#else
+ /* Push envp, argc, and argc arguments to __uClibc_start_main() on the stack */
+ pushq %rbx /* Environment pointer */
+ pushq %rdx /* Argument pointer */
+ pushq %rsi /* And the argument count */
+
+#ifdef L_Scrt0
+ call *__uClibc_main@GOT(%rip)
+#else
+ call __uClibc_main
+#endif
+#endif
+/* END TODO *
+ ************/
+
+ hlt /* Crash if somehow `exit' does return. */
+.size _start,.-_start
+
+/* Define a symbol for the first piece of initialized data. */
+ .data
+ .globl __data_start
+__data_start:
+ .long 0
+ .weak data_start
+ data_start = __data_start
diff --git a/libc/sysdeps/linux/x86_64/crti.S b/libc/sysdeps/linux/x86_64/crti.S
new file mode 100644
index 000000000..6a29f2bc0
--- /dev/null
+++ b/libc/sysdeps/linux/x86_64/crti.S
@@ -0,0 +1,14 @@
+/* glibc's sysdeps/x86_64/elf/initfini.c used for reference [PROLOG] */
+
+.section .init
+.globl _init
+.type _init, @function
+_init:
+ subq $8, %rsp
+
+
+.section .fini
+.globl _fini
+.type _fini, @function
+_fini:
+ subq $8, %rsp