diff options
Diffstat (limited to 'sysdeps/s390/s390-64/elf/start.S')
| -rw-r--r-- | sysdeps/s390/s390-64/elf/start.S | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/sysdeps/s390/s390-64/elf/start.S b/sysdeps/s390/s390-64/elf/start.S new file mode 100644 index 0000000..d85c080 --- /dev/null +++ b/sysdeps/s390/s390-64/elf/start.S @@ -0,0 +1,84 @@ +/* Startup code compliant to the 64 bit S/390 ELF ABI. + Copyright (C) 2001 Free Software Foundation, Inc. + Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com). + 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., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +/* + This is the canonical entry point, usually the first thing in the text + segment. Most registers' values are unspecified, except for: + + %r14 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. + + %r15 The stack contains the arguments and environment: + 0(%r15) argc + 8(%r15) argv[0] + ... + (8*argc)(%r15) NULL + (8*(argc+1))(%r15) envp[0] + ... + NULL +*/ + + .text + .globl _start +_start: + /* Load argc and argv from stack. */ + la %r4,8(%r15) # get argv + lg %r3,0(%r15) # get argc + + /* Align the stack to a double word boundary. */ + lghi %r0,-16 + ngr %r15,%r0 + + /* Setup a stack frame and a parameter area. */ + aghi %r15,-176 # make room on stack + xc 0(8,%r15),0(%r15) # clear back-chain + + /* Set up arguments for __libc_start_main: + main, argc, argv, envp, _init, _fini, rtld_fini, stack_end + Note that envp will be determined later in __libc_start_main. + */ + stmg %r14,%r15,160(%r15) # store rtld_fini/stack_end to parameter area + la %r7,160(%r15) + larl %r6,_fini # load pointer to _fini + larl %r5,_init # load pointer to _init + larl %r2,main # load pointer to main + + /* Ok, now branch to the libc main routine. */ + brasl %r14,__libc_start_main + + /* Crash if __libc_start_main returns. */ + .word 0 + + /* FIXME: FPU flags or what ?!? */ + + .section .rodata + .globl _fp_hw + .long 3 + .size _fp_hw, 4 + + /* 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 |