/*
;  i386-darwin.macho-upxsubr.S -- system calls, bswap, bzero (i386 Mach-o)
;
;  This file is part of the UPX executable compressor.
;
;  Copyright (C) 1996-2020 Markus Franz Xaver Johannes Oberhumer
;  Copyright (C) 1996-2020 Laszlo Molnar
;  Copyright (C) 2000-2020 John F. Reiser
;  All Rights Reserved.
;
;  UPX and the UCL library are free software; you can redistribute them
;  and/or modify them under the terms of the GNU General Public License as
;  published by the Free Software Foundation; either version 2 of
;  the License, or (at your option) any later version.
;
;  This program 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 General Public License for more details.
;
;  You should have received a copy of the GNU General Public License
;  along with this program; see the file COPYING.
;  If not, write to the Free Software Foundation, Inc.,
;  59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
;
;  Markus F.X.J. Oberhumer              Laszlo Molnar
;  <markus@oberhumer.com>               <ml1050@users.sourceforge.net>
;
;  John F. Reiser
;  <jreiser@users.sourceforge.net>
;
*/
// Prepend one underscore
#define GLOBAL(sym) _##sym: .globl _##sym

GLOBAL(bswap)
        mov 1*4(%esp),%edx  // ptr
        mov 2*4(%esp),%ecx  // len
0:
        mov (%edx),%eax  // value
        .byte 0x0f,0xc8  // bswap eax
        mov %eax,(%edx)
        sub $4,%ecx
        lea 4(%edx),%edx
        ja 0b
        ret

GLOBAL(bzero)
GLOBAL(__bzero)
        pop %edx  // retaddr
        pop %eax  // ptr
        pop %ecx  // len
        push %ecx
        push %eax
        push %edx

        push %edi
        xchg %eax,%edi  // ptr
        xor %eax,%eax  // the value
        rep; stosb  // *edi++ = %al
        pop %edi

        ret

SYS_exit  =1
SYS_read  =3
SYS_write =4
SYS_open  =5
SYS_close =6

SYS_pread    =0x99
SYS_mmap     =0xc5
SYS_munmap   =0x49
SYS_mprotect =0x4a

sysgo:
        pop %edx  // return address for sysenter
        .byte 0x0f,0x34  // sysenter

// lazy jmps enable compression of this code
GLOBAL(write)
        mov $SYS_write,%al;  .word 0x02eb
GLOBAL(exit)
        mov $SYS_exit,%al;  .word 0x02eb
GLOBAL(mprotect)
        mov $SYS_mprotect,%al; .word 0x02eb
GLOBAL(munmap)
        mov $SYS_munmap,%al; .word 0x02eb
GLOBAL(pread)
        mov $SYS_pread,%al; .word 0x02eb
GLOBAL(close)
        mov $SYS_close,%al; .word 0x02eb
GLOBAL(open)
        mov $SYS_open,%al;  .word 0x02eb
GLOBAL(mmap)
        mov $SYS_mmap,%al;  .word 0x02eb
GLOBAL(read)
        mov $SYS_read,%al

        movzbl %al,%eax
        mov %esp,%ecx  // &{user_ra, arg1, arg2, ...}
        or $0xC0000,%eax
        call sysgo; jnc 0f
        or $~0,%eax  // mov %eax,errno
0:
        ret
