source: mainline/uspace/lib/c/arch/ia32/src/entry.S@ a35b458

#
# Copyright (c) 2005 Martin Decky
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

#include <abi/asmtool.h>

INTEL_CPUID_STANDARD = 1
INTEL_SEP = 11

.section .init, "ax"

.org 0

## User-space task entry point
#
# %edi contains the PCB pointer
#
SYMBOL(__entry)
        mov %ss, %ax
        mov %ax, %ds
        mov %ax, %es
        mov %ax, %fs
        # Do not set %gs, it contains descriptor that can see TLS

#ifndef PROCESSOR_i486
        # Detect the mechanism used for making syscalls
        movl $(INTEL_CPUID_STANDARD), %eax
        cpuid
        bt $(INTEL_SEP), %edx
        jnc 0f
                leal __syscall_fast_func, %eax
                movl $__syscall_fast, (%eax)
        0:
#endif

        #
        # Create the first stack frame.
        #
        pushl $0
        pushl $0
        movl %esp, %ebp

        # Pass the PCB pointer to __main as the first argument
        pushl %edi
        call __main