diff options
Diffstat (limited to 'libc/sysdeps/linux/or1k/crt1.S')
| -rw-r--r-- | libc/sysdeps/linux/or1k/crt1.S | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/or1k/crt1.S b/libc/sysdeps/linux/or1k/crt1.S new file mode 100644 index 000000000..c1926bef2 --- /dev/null +++ b/libc/sysdeps/linux/or1k/crt1.S @@ -0,0 +1,144 @@ +/* Copyright (C) 1995, 1996, 1997, 1998, 2001, 2002, 2005 + Free Software Foundation, Inc. + + Copyright (C) 2010 Embecosm Limited + + Contributor Jeremy Bennett <jeremy.bennett@embecosm.com> + Contributor Joern Rennecke <joern.rennecke@embecosm.com> + With other contributions from the OpenCores community. + + 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 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. */ + +/* 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 + +/* This is the canonical entry point, usually the first thing in the text + segment. + + sp The stack contains the arguments and environment: + 0(sp) argc + 4(sp) argv[0] + ... + (4*argc)(sp) NULL + (4*(argc+1))(sp) envp[0] + ... + NULL +*/ + +#include <features.h> + +.text + .globl _start + .type _start,%function + +.global _start +_start: + +#ifdef __PIC__ + /* Obtain a pointer to .got in r16 */ + l.jal .LPC0 +#ifndef __OR1K_NODELAY__ + l.nop +#endif +.LPC0: + l.movhi r16, gotpchi(_GLOBAL_OFFSET_TABLE_+(.-.LPC0)) + l.ori r16, r16, gotpclo(_GLOBAL_OFFSET_TABLE_+(.-.LPC0)) + l.add r16, r16, r9 +#endif + + /* Push stack limit onto the stack */ + /* Provides highest stack address to user code (as stack grows + * downwards + * This is the seventh argument to __uClibc_main and thus needs to + * be passed on the stack + */ + l.sw -4(r1),r1 + + /* Take values for argc and argv off the stack. + * These will be passed as arguments two and three to __uClibc_main + * and thus go in registers r4 and r5, respectively + */ + l.lwz r4,0(r1) + l.addi r5,r1,4 + +#ifdef __PIC__ + l.lwz r3,got(main)(r16) +#else + l.movhi r3,hi(main) + l.ori r3,r3,lo(main) +#endif + + /* Put the constructor and destructor initialization as args four and + five into r6 and r7 */ +#ifdef __PIC__ + l.lwz r6, got(_init)(r16) + l.lwz r7, got(_fini)(r16) +#else + l.movhi r6,hi(_init) + l.ori r6,r6,lo(_init) + l.movhi r7,hi(_fini) + l.ori r7,r7,lo(_fini) +#endif + + /* rtld_fini = NULL */ + l.movhi r8, 0 + + /* Adjust stack to account for a total of 7 args (i.e. the last one is + on the stack. */ + l.addi r1,r1,-4 + + /* Clear the frame pointer and link register since this is the + * outermost frame. + */ + l.add r2,r0,r0 + l.add r9,r0,r0 + + /* Let the libc call main and exit with its return code. */ +#ifdef __PIC__ + l.j plt(__uClibc_main) +#else + l.j __uClibc_main +#endif + l.nop + +/* 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 |