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/* Copyright (C) 1996 Robert de Bath <robert@mayday.compulink.co.uk>
* This file is part of the Linux-8086 C library and is distributed
* under the GNU Library General Public License.
*/
#undef AOUT_STANDALONE
#if !__FIRST_ARG_IN_AX__
#ifdef __AS386_16__
#ifdef __STANDALONE__
#include <bios.h>
#include <fcntl.h>
#include <errno.h>
#ifdef L_bios_start
char ** environ = { 0 };
int errno;
void (*__cleanup)() = 0;
#asm
.data
export ___argr
___argr:
.word 0,0,0,0,0,0,0,0 ! A struct REGS: ax, bx, cx, dx, si, di, cflag, flags
defarg:
.word boot_str, 0
boot_str:
.asciz "boot"
loop_save:
.word 0
.text
export ___cstartup ! Crt0 startup
___cstartup:
cli
#ifndef AOUT_STANDALONE
seg cs
cmp word ptr [0],#$20CD ! "int 20h" at psp: CS:0000
jne not_dos
! DOS - only AX has a defined value.
! All the segment registers are pointing at the PSP
! SP points to the top of the segment so is probably useable.
push ax ! Save AX
mov ax,cs
add ax,#$10 ! bump CS by 0x10
push ax
mov ax,#is_dos ! resume address
push ax
retf ! continue at next instruction
dos_flag:
.word 0 ! Set to 1 if DOS
is_dos:
seg cs
inc dos_flag
pop ax ! restore saved AX
not_dos:
mov sp,cs
add sp,#__segoff
mov ds,sp
mov ss,sp
mov bp,#__heap_top
mov sp,#___argr+14
seg cs
push [dos_flag] ! Set the carry flag if we're under DOS.
#else
mov bp,sp
mov sp,#___argr+12
#endif
push di
push si
push dx
push cx
push bx
push ax
mov sp,bp
sti
zap_bss: ! Clear the BSS
mov ax,ds
mov es,ax ! ES now data seg
mov di,#__edata
mov cx,#__end
sub cx,di
xor ax,ax
cld
rep
stosb
!mov bp,ax ! Top frame pointer, only needed if we get a debugger
push [_environ]
mov ax,#defarg ! Don`t define __mkargv, standalone programs don`t
push ax ! get any arguments.
mov ax,#1
push ax
mov bx,#auto_start ! Pointer to first autostart function
auto_run:
mov [loop_save],bx
mov bx,[bx]
test bx,bx
jz no_entry
call bx ! Call the function
no_entry:
mov bx,[loop_save]
inc bx ! next
inc bx
jmp auto_run ! And round for the next.
call_exit: ! Last item called by above.
pop bx ! Be tidy.
push ax ! At the end the last called was main() push it`s
call _exit ! return val and call exit();
bad_exit:
jmp bad_exit ! Exit returned !!
loc 2
.word _main ! Segment 2 is the trailing pointers, main and the
.word call_exit ! routine to call exit.
data_start:
.text
export _exit
_exit: ! exit(rv) function
mov bx,sp
push [bx+2] ! Copy the `rv` for the exit fuctions.
mov bx,[___cleanup] ! Call exit, normally this is `__do_exit`
test bx,bx
je no_clean ! But it`s default is null
call bx
no_clean:
inc sp
inc sp
export __exit
__exit:
#ifndef AOUT_STANDALONE
seg cs
cmp [dos_flag],#0 ! Should we do a DOS exit
je do_reboot
int #$20
do_reboot:
#endif
xor ax,ax
mov es,ax
mov ax,cs
seg es
mov [$E6*4+2],ax
mov ax,#iret_ins
seg es
mov [$E6*4],ax
mov ax,#$FFFF
int $E6 ! Try to exit DOSEMU
! If we get here we`re not in dosemu.
seg es
mov [$472],#$1234 ! Warm reboot.
jmpi $0000,$FFFF
iret_ins:
iret
#endasm
#endif
/****************************************************************************/
#ifdef L_bios_write
write(fd,buf,len)
int fd,len;
char * buf;
{
register int v, c;
if(fd == 1 || fd == 2)
{
for(v=len; v>0; v--)
{
c= *buf++;
putch(c);
}
return len;
}
return (*__files)(CMD_WRITE, fd, buf, len);
}
#endif
/****************************************************************************/
#ifdef L_bios_read
read(fd,buf,len)
int fd,len;
char * buf;
{
if(fd == 0) return bios_rdline(buf, len);
return (*__files)(CMD_READ, fd, buf, len);
}
#endif
/****************************************************************************/
#ifdef L_bios_lseek
long
lseek(fd, offt, whence)
int fd, whence;
long offt;
{
if( fd >= 0 && fd <= 2 ) errno = ESPIPE;
else
{
if( (*__files)(CMD_LSEEK, fd, &offt, whence) >= 0 )
return offt;
}
return -1L;
}
#endif
/****************************************************************************/
#ifdef L_bios_close
close(fd)
int fd;
{
if( fd >= 0 && fd <= 2 ) errno = ENOSYS;
else
return (*__files)(CMD_CLOSE, fd);
return -1;
}
#endif
/****************************************************************************/
#ifdef L_bios_nofiles
int (*__files)() = __nofiles;
int __nofiles(cmd, fd, buf, len)
int cmd, fd, len;
char * buf;
{
errno = EBADF;
return -1;
}
#endif
/****************************************************************************/
#ifdef L_bios_isatty
isatty(fd)
int fd;
{
if( fd >= 0 && fd <= 2 ) return 1;
return 0;
}
#endif
/****************************************************************************/
#endif
#endif
#endif
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