{
    This file is part of the Free Pascal run time library.
    Copyright (c) 2001 by Free Pascal development team

    This file implements all the base types and limits required
    for a minimal POSIX compliant subset required to port the compiler
    to a new OS.

    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.

 **********************************************************************}

const
  carryflag = 1;

type
  tseginfo=packed record
    offset  : pointer;
    segment : word;
  end;

var
  old_int00 : tseginfo;cvar;
  old_int75 : tseginfo;cvar;

{$asmmode ATT}

{*****************************************************************************
                              Go32 Helpers
*****************************************************************************}

function far_strlen(selector : word;linear_address : longint) : longint;assembler;
asm
        movl linear_address,%edx
        movl %edx,%ecx
        pushl %gs
        movw selector,%gs
.Larg19:
        movb %gs:(%edx),%al
        testb %al,%al
        je .Larg20
        incl %edx
        jmp .Larg19
.Larg20:
        popl %gs
        movl %edx,%eax
        subl %ecx,%eax
end;


function tb : longint;
begin
  tb:=go32_info_block.linear_address_of_transfer_buffer;
end;


function tb_segment : longint;
begin
  tb_segment:=go32_info_block.linear_address_of_transfer_buffer shr 4;
end;


function tb_offset : longint;
begin
  tb_offset:=go32_info_block.linear_address_of_transfer_buffer and $f;
end;


function tb_size : longint;
begin
  tb_size:=go32_info_block.size_of_transfer_buffer;
end;


function dos_selector : word;
begin
  dos_selector:=go32_info_block.selector_for_linear_memory;
end;


function get_ds : word;assembler;
asm
        movw    %ds,%ax
end;


function get_cs : word;assembler;
asm
        movw    %cs,%ax
end;


procedure sysseg_move(sseg : word;source : longint;dseg : word;dest : longint;count : longint);
begin
   if count=0 then
     exit;
   if (sseg<>dseg) or ((sseg=dseg) and (source>dest)) then
     asm
        pushl %esi
        pushl %edi
        pushw %es
        pushw %ds
        cld
        movl count,%ecx
        movl source,%esi
        movl dest,%edi
        movw dseg,%ax
        movw %ax,%es
        movw sseg,%ax
        movw %ax,%ds
        movl %ecx,%eax
        shrl $2,%ecx
        rep
        movsl
        movl %eax,%ecx
        andl $3,%ecx
        rep
        movsb
        popw %ds
        popw %es
        popl %edi
        popl %esi
     end
   else if (source<dest) then
     { copy backward for overlapping }
     asm
        pushl %esi
        pushl %edi
        pushw %es
        pushw %ds
        std
        movl count,%ecx
        movl source,%esi
        movl dest,%edi
        movw dseg,%ax
        movw %ax,%es
        movw sseg,%ax
        movw %ax,%ds
        addl %ecx,%esi
        addl %ecx,%edi
        movl %ecx,%eax
        andl $3,%ecx
        orl %ecx,%ecx
        jz .LSEG_MOVE1

        { calculate esi and edi}
        decl %esi
        decl %edi
        rep
        movsb
        incl %esi
        incl %edi
     .LSEG_MOVE1:
        subl $4,%esi
        subl $4,%edi
        movl %eax,%ecx
        shrl $2,%ecx
        rep
        movsl
        cld
        popw %ds
        popw %es
        popl %edi
        popl %esi
     end;
end;


function strcopy(dest,source : PAnsiChar) : PAnsiChar;assembler;
var
  saveeax,saveesi,saveedi : longint;
asm
        movl    %edi,saveedi
        movl    %esi,saveesi
{$ifdef REGCALL}
        movl    %eax,saveeax
        movl    %edx,%edi
{$else}
        movl    source,%edi
{$endif}
        testl   %edi,%edi
        jz      .LStrCopyDone
        leal    3(%edi),%ecx
        andl    $-4,%ecx
        movl    %edi,%esi
        subl    %edi,%ecx
{$ifdef REGCALL}
        movl    %eax,%edi
{$else}
        movl    dest,%edi
{$endif}
        jz      .LStrCopyAligned
.LStrCopyAlignLoop:
        movb    (%esi),%al
        incl    %edi
        incl    %esi
        testb   %al,%al
        movb    %al,-1(%edi)
        jz      .LStrCopyDone
        decl    %ecx
        jnz     .LStrCopyAlignLoop
        .balign  16
.LStrCopyAligned:
        movl    (%esi),%eax
        movl    %eax,%edx
        leal    0x0fefefeff(%eax),%ecx
        notl    %edx
        addl    $4,%esi
        andl    %edx,%ecx
        andl    $0x080808080,%ecx
        jnz     .LStrCopyEndFound
        movl    %eax,(%edi)
        addl    $4,%edi
        jmp     .LStrCopyAligned
.LStrCopyEndFound:
        testl   $0x0ff,%eax
        jz      .LStrCopyByte
        testl   $0x0ff00,%eax
        jz      .LStrCopyWord
        testl   $0x0ff0000,%eax
        jz      .LStrCopy3Bytes
        movl    %eax,(%edi)
        jmp     .LStrCopyDone
.LStrCopy3Bytes:
        xorb     %dl,%dl
        movw     %ax,(%edi)
        movb     %dl,2(%edi)
        jmp     .LStrCopyDone
.LStrCopyWord:
        movw    %ax,(%edi)
        jmp     .LStrCopyDone
.LStrCopyByte:
        movb    %al,(%edi)
.LStrCopyDone:
{$ifdef REGCALL}
        movl    saveeax,%eax
{$else}
        movl    dest,%eax
{$endif}
        movl    saveedi,%edi
        movl    saveesi,%esi
end;


procedure syscopytodos(addr : longint; len : longint);
begin
   if len > tb_size then
     HandleError(217);
   sysseg_move(get_ds,addr,dos_selector,tb,len);
end;


procedure syscopyfromdos(addr : longint; len : longint);
begin
   if len > tb_size then
     HandleError(217);
   sysseg_move(dos_selector,tb,get_ds,addr,len);
end;


procedure sysrealintr(intnr : word;var regs : trealregs);
begin
   regs.realsp:=0;
   regs.realss:=0;
   regs.realres:=0; { spec says so, play it safe }
   asm
      pushl %ebx
      pushl %edi
      pushl %fs   // Go32.RealIntr does it too (NTVDM bug),
                  // "pushl" to avoid size prefix
      movw  intnr,%bx
      xorl  %ecx,%ecx
      movl  regs,%edi
      movw  $0x300,%ax
      int   $0x31
      popl  %fs
      popl  %edi
      popl  %ebx
   end;
end;


procedure set_pm_interrupt(vector : byte;const intaddr : tseginfo);
begin
  asm
        pushl   %ebx
        movl intaddr,%eax
        movl (%eax),%edx
        movw 4(%eax),%cx
        movl $0x205,%eax
        movb vector,%bl
        int $0x31
        popl  %ebx
  end;
end;


procedure get_pm_interrupt(vector : byte;var intaddr : tseginfo);
begin
  asm
        pushl   %ebx
        movb    vector,%bl
        movl    $0x204,%eax
        int     $0x31
        movl    intaddr,%eax
        movl    %edx,(%eax)
        movw    %cx,4(%eax)
        popl  %ebx
  end;
end;


procedure getinoutres(def : word);
var
  regs : trealregs;
begin
  regs.realeax:=$5900;
  regs.realebx:=$0;
  sysrealintr($21,regs);
  InOutRes:=lo(regs.realeax);
  case InOutRes of
   19 : InOutRes:=150;
   21 : InOutRes:=152;
   32 : InOutRes:=5;
  end;
  if InOutRes=0 then
    InOutRes:=Def;
end;