diff --git a/rtl/i8086/i8086.inc b/rtl/i8086/i8086.inc
index c19d7b6aa2..59e936179c 100644
--- a/rtl/i8086/i8086.inc
+++ b/rtl/i8086/i8086.inc
@@ -17,3 +17,75 @@
 procedure fpc_cpuinit;
   begin
   end;
+
+{$define FPC_SYSTEM_HAS_SPTR}
+Function Sptr : Pointer;assembler;nostackframe;
+asm
+  mov ax, sp
+end;
+
+{$define FPC_SYSTEM_HAS_GET_CALLER_ADDR}
+function get_caller_addr(framebp:pointer;addr:pointer=nil):pointer;nostackframe;assembler;
+asm
+  or ax, ax
+  jz @@Lg_a_null
+  xchg ax, bx
+  mov bx, [bx+2]
+  xchg ax, bx
+@@Lg_a_null:
+end;
+
+{$define FPC_SYSTEM_HAS_GET_CALLER_FRAME}
+function get_caller_frame(framebp:pointer;addr:pointer=nil):pointer;nostackframe;assembler;
+asm
+  or ax, ax
+  jz @@Lgnf_null
+  xchg ax, bx
+  mov bx, [bx]
+  xchg ax, bx
+@@Lgnf_null:
+end;
+
+{TODO: fix, use smallint?}
+function InterLockedDecrement (var Target: longint) : longint; assembler;
+asm
+  push bx
+  mov bx, ax
+  sub word [bx], 1
+  sbb word [bx+2], 0
+  mov ax, [bx]
+  mov dx, [bx+2]
+  pop bx
+end;
+
+{TODO: fix, use smallint?}
+function InterLockedIncrement (var Target: longint) : longint; assembler;
+asm
+  push bx
+  mov bx, ax
+  add word [bx], 1
+  adc word [bx+2], 0
+  mov ax, [bx]
+  mov dx, [bx+2]
+  pop bx
+end;
+
+{TODO: fix, use smallint?}
+function InterLockedExchange (var Target: longint;Source : longint) : longint;
+begin
+  InterLockedExchange := Target;
+  Target := Source;
+end;
+
+{TODO: implement}
+function InterLockedExchangeAdd (var Target: longint;Source : longint) : longint;
+begin
+  runerror(304);
+end;
+
+{TODO: implement}
+function InterlockedCompareExchange(var Target: longint; NewValue: longint; Comperand: longint): longint;
+begin
+  runerror(304);
+end;
+