diff --git a/rtl/inc/compproc.inc b/rtl/inc/compproc.inc
index 862a049e31..c3aaf268df 100644
--- a/rtl/inc/compproc.inc
+++ b/rtl/inc/compproc.inc
@@ -40,7 +40,7 @@ procedure fpc_zeromem(p:pointer;len:ptruint);compilerproc;
 procedure fpc_fillmem(out data;len:ptruint;b : byte);compilerproc;
 
 procedure fpc_Shortstr_SetLength(var s:shortstring;len:SizeInt); compilerproc;
-procedure fpc_shortstr_assign(len:longint;sstr,dstr:pointer); compilerproc;
+procedure fpc_shortstr_assign(len:{$ifdef cpu16}smallint{$else}longint{$endif};sstr,dstr:pointer); compilerproc;
 procedure fpc_shortstr_to_shortstr(out res:shortstring; const sstr: shortstring); compilerproc;
 
 procedure fpc_shortstr_concat(var dests:shortstring;const s1,s2:shortstring);compilerproc;
diff --git a/rtl/inc/generic.inc b/rtl/inc/generic.inc
index d40d04e862..4ded841654 100644
--- a/rtl/inc/generic.inc
+++ b/rtl/inc/generic.inc
@@ -892,7 +892,7 @@ begin
   res[0]:=chr(slen);
 end;
 
-procedure fpc_shortstr_assign(len:longint;sstr,dstr:pointer);[public,alias:'FPC_SHORTSTR_ASSIGN']; compilerproc;
+procedure fpc_shortstr_assign(len:{$ifdef cpu16}smallint{$else}longint{$endif};sstr,dstr:pointer);[public,alias:'FPC_SHORTSTR_ASSIGN']; compilerproc;
 var
   slen : byte;
 begin