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{
This file is part of the Free Pascal run time library.
Copyright (c) 1999-2000 by Pierre Muller
FPU Emulator support
See the file COPYING.FPC, included in this distribution,
for details about the copyright.
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.
**********************************************************************}
unit emu387;
interface
procedure npxsetup(prog_name : string);
implementation
{$asmmode ATT}
uses
dxeload,dpmiexcp,strings;
type
emu_entry_type = function(exc : pexception_state) : longint;
var
_emu_entry : emu_entry_type;
procedure _control87(mask1,mask2 : longint);
begin
{ Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details }
{ from file cntrl87.s in src/libc/pc_hw/fpu }
asm
{ make room on stack }
pushl %eax
fstcw (%esp)
fwait
popl %eax
andl $0xffff, %eax
{ OK; we have the old value ready }
movl mask2, %ecx
notl %ecx
andl %eax, %ecx { the bits we want to keep }
movl mask2, %edx
andl mask1, %edx { the bits we want to change }
orl %ecx, %edx { the new value }
pushl %edx
fldcw (%esp)
popl %edx
end;
end;
{ the problem with the stack that is not cleared }
function emu_entry(exc : pexception_state) : longint;
begin
emu_entry:=_emu_entry(exc);
end;
function nofpsig( sig : longint) : longint;cdecl;
const
last_eip : longint = 0;
var
res : longint;
begin
{if last_eip=djgpp_exception_state^.__eip then
begin
writeln('emu call two times at same address');
dpmi_set_coprocessor_emulation(1);
_raise(SIGFPE);
exit(0);
end; }
last_eip:=djgpp_exception_state^.__eip;
res:=emu_entry(djgpp_exception_state);
if res<>0 then
begin
writeln('emu call failed. res = ',res);
dpmi_set_coprocessor_emulation(1);
_raise(SIGFPE);
exit(0);
end;
dpmi_longjmp(pdpmi_jmp_buf(djgpp_exception_state)^, djgpp_exception_state^.__eax);
nofpsig:=0;
end;
var
prev_exit : pointer;
procedure restore_DPMI_fpu_state;
begin
exitproc:=prev_exit;
{ Enable Coprocessor, no exceptions }
dpmi_set_coprocessor_emulation(1);
{$ifdef SYSTEMDEBUG}
writeln(stderr,'Coprocessor restored ');
{$endif}
end;
{ function _detect_80387 : boolean;
not used because of the underscore problem }
{$L fpu.o }
function getenv(const envvar:string):string;
{ Copied here, preserves uses Dos (PFV) }
var
hp : ppchar;
hs,
_envvar : string;
eqpos : longint;
begin
_envvar:=upcase(envvar);
hp:=envp;
getenv:='';
while assigned(hp^) do
begin
hs:=strpas(hp^);
eqpos:=pos('=',hs);
if copy(hs,1,eqpos-1)=_envvar then
begin
getenv:=copy(hs,eqpos+1,255);
exit;
end;
inc(hp);
end;
end;
function __detect_80387:byte;external name '__detect_80387';
procedure npxsetup(prog_name : string);
var
cp : string;
i : byte;
have_80387 : boolean;
emu_p : pointer;
const
veryfirst : boolean = True;
begin
cp:=getenv('387');
if (length(cp)>0) and (upcase(cp[1])='N') then
have_80387:=False
else
begin
dpmi_set_coprocessor_emulation(1);
asm
call __detect_80387
movb %al,have_80387
end;
end;
if (length(cp)>0) and (upcase(cp[1])='Q') then
begin
if not have_80387 then
write(stderr,'No ');
writeln(stderr,'80387 detected.');
end;
if have_80387 then
begin
{ mask all exceptions, except invalid operation }
{ change to same value as in v2prt0.as (PM) }
_control87($0332, $ffff)
end
else
begin
{ Flags value 3 means coprocessor emulation, exceptions to us }
if (dpmi_set_coprocessor_emulation(3)<>0) then
begin
writeln(stderr,'Warning: Coprocessor not present and DPMI setup failed!');
writeln(stderr,' If application attempts floating operations system may hang!');
end
else
begin
cp:=getenv('EMU387');
if length(cp)=0 then
begin
for i:=length(prog_name) downto 1 do
if prog_name[i] in AllowDirectorySeparators then
break;
if i>1 then
cp:=copy(prog_name,1,i);
cp:=cp+'wmemu387.dxe';
end;
emu_p:=dxe_load(cp);
_emu_entry:=emu_entry_type(emu_p);
if (emu_p=nil) then
begin
writeln(cp+' load failed !');
halt;
end;
if veryfirst then
begin
veryfirst:=false;
prev_exit:=exitproc;
exitproc:=@restore_DPMI_fpu_state;
end;
signal(SIGNOFP,@nofpsig);
end;
end;
end;
begin
npxsetup(paramstr(0));
end.
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