/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* This crt1.o module is provided as the bare minimum required to build a
* where it will be picked up by gcc, along with crti.o and crtn.o
*/
.ident "%Z%%M% %I% %E% SMI"
/* global entities defined elsewhere but used here */
.align 8
.align 8
.align 8
/*
* point runs registers' %rbp, %rsp, %rdx values are specified
* the following:
*
* %rbp The content of this register is unspecified at
* process initialization time, but the user code should mark
* the deepest stack frame by setting the frame pointer to zero.
* No other frame's %ebp should have a zero value.
*
* %rsp Performing its usual job, the stack pointer holds the address
* of the bottom of the stack, which is guaranteed to be
* quadword aligned.
*
* The stack contains the arguments and environment:
* ...
* envp[0] (16+(8*argc))(%rsp)
* NULL (8+(8*argc))(%rsp)
* ...
* argv[0] 8(%rsp)
* argc 0(%rsp)
*
* %rdx In a conforming program, this register contains a function
* pointer that the application should register with atexit(BA_OS).
* This function is used for shared object termination code
* [see Dynamic Linking in Chapter 5 of the System V ABI].
*
*/
/*
* Allocate a NULL return address and a NULL previous %rbp as if
* there was a genuine call to _start.
*/
pushq $0
pushq $0
/*
* The stack now is
*
* envp[0] (32+(8*argc))(%rsp) - (A)
* NULL (24+(8*argc))(%rsp)
* ...
* argv[0] 24(%rbp) - (B)
* argc 16(%rbp)
* 0 8(%rbp)
* 0 0(%rbp)
*/
/*
* Check to see if there is an _mcleanup() function linked in, and if so,
* register it with atexit() as the last thing to be run by exit().
*/
jz 1f
1:
jz 1f
1:
/* start profiling */
/*
* Calculate the location of the envp array by adding the size of
* the argv array to the start of the argv array.
*/
jne 1f
1:
/*
* Force stack alignment - below here there must have been an even
* number of un-popped pushq instructions whenever a call is reached
*/