diff --git a/sys/jit/kern_jit.pas b/sys/jit/kern_jit.pas
index d0a4533d..2f469572 100644
--- a/sys/jit/kern_jit.pas
+++ b/sys/jit/kern_jit.pas
@@ -32,11 +32,21 @@ uses
  kern_jit_ops_avx,
  kern_jit_dynamic,
  kern_jit_test,
- kern_jit_asm;
+ kern_jit_asm,
+ kern_thr,
+ subr_backtrace;
 
-procedure jit_assert;
+procedure _jit_assert;
 begin
- Assert(False,'jit_assert');
+ jit_save_to_sys_save(curkthread);
+ print_error_td('Assert in guest code!');
+ Assert(false);
+end;
+
+procedure jit_assert; assembler; nostackframe;
+asm
+ call jit_save_ctx
+ jmp  _jit_assert
 end;
 
 procedure jit_system_error;
diff --git a/sys/jit/kern_jit_asm.pas b/sys/jit/kern_jit_asm.pas
index 748ee8f8..cb58faf2 100644
--- a/sys/jit/kern_jit_asm.pas
+++ b/sys/jit/kern_jit_asm.pas
@@ -56,6 +56,12 @@ procedure jit_jmp_internal;  assembler;
 
 function  IS_JIT_FUNC(rip:qword):Boolean;
 
+procedure jit_save_ctx;
+procedure jit_load_ctx;
+
+procedure jit_save_to_sys_save(td:p_kthread);
+procedure sys_save_to_jit_save(td:p_kthread);
+
 implementation
 
 uses
@@ -71,9 +77,6 @@ function jmp_dispatcher(addr,plt:Pointer):Pointer; external;
 
 //
 
-procedure jit_save_ctx; forward;
-procedure jit_load_ctx; forward;
-
 procedure jit_sigsegv(addr:Pointer);
 begin
  print_error_td('jit_sigsegv:0x'+HexStr(addr));
diff --git a/sys/jit/kern_jit_ops_avx.pas b/sys/jit/kern_jit_ops_avx.pas
index 3b3fa035..855d6245 100644
--- a/sys/jit/kern_jit_ops_avx.pas
+++ b/sys/jit/kern_jit_ops_avx.pas
@@ -422,7 +422,7 @@ begin
 end;
 
 const
- vmov_ss_sd_desc:t_op_desc=(
+ vmov_ss_desc:t_op_desc=(
   mem_reg:(op:$11;simdop:2;mm:1);
   reg_mem:(op:$10;simdop:2;mm:1);
   reg_imm:(opt:[not_impl]);
@@ -431,11 +431,18 @@ const
  );
 
 procedure op_vmov_ss_sd(var ctx:t_jit_context2);
+var
+ desc:t_op_desc;
 begin
  if is_preserved(ctx.din) or is_memory(ctx.din) then
  begin
   case ctx.din.OperCnt of
-   2:op_emit_avx2(ctx,vmov_ss_sd_desc);
+   2:begin
+      desc:=vmov_ss_desc;
+      desc.mem_reg.simdop:=SCODES[ctx.dis.SimdOpcode];
+      desc.reg_mem.simdop:=SCODES[ctx.dis.SimdOpcode];
+      op_emit_avx2(ctx,desc);
+     end;
    3:op_avx3_not_vex_len(ctx);
    else
     Assert(False);
diff --git a/sys/md/vm_pmap.pas b/sys/md/vm_pmap.pas
index 693a5ad9..98aeacc2 100644
--- a/sys/md/vm_pmap.pas
+++ b/sys/md/vm_pmap.pas
@@ -279,11 +279,13 @@ procedure get_dmem_fd(var info:t_fd_info);
 var
  o:QWORD;
  e:QWORD;
+ d:QWORD;
  i:DWORD;
  r:DWORD;
 begin
  o:=info.offset;
 
+ //current block id
  i:=o shr PMAPP_1GB_SHIFT;
 
  if (DMEM_FD[i].hfile=0) then
@@ -303,12 +305,21 @@ begin
 
  vm_nt_file_obj_reference(info.obj);
 
- e:=o+(info.__end-info.start);
+ //current block offset
+ o:=o and PMAPP_1GB_MASK;
 
+ //mem size
+ d:=info.__end-info.start;
+
+ //max offset
+ e:=o+d;
+
+ // |start         end|
+ // |offset  |max
  if (e>PMAPP_1GB_SIZE) then
  begin
-  e:=PMAPP_1GB_SIZE;
-  e:=(e-o)+info.start;
+  e:=PMAPP_1GB_SIZE-o;
+  e:=e+info.start;
   info.__end:=e;
  end;
 end;
@@ -506,17 +517,17 @@ begin
 
       info.start:=start;
       info.__end:=__end;
-      info.offset:=0;
 
       while (info.start<>info.__end) do
       begin
        get_private_fd(info);
 
        delta:=(info.__end-info.start);
+       if (delta=0) then Break;
 
        r:=vm_nt_map_insert(@pmap^.nt_map,
                            info.obj,
-                           info.offset,
+                           0, //private always from the start
                            info.start,
                            info.__end,
                            delta,
@@ -530,7 +541,6 @@ begin
 
        info.start :=info.start+delta;
        info.__end :=__end;
-       info.offset:=0;
       end;
 
     end;
@@ -547,7 +557,7 @@ begin
      begin
       if (p_print_pmap<>0) then
       begin
-       Writeln('pmap_enter_gpuobj:',HexStr(start,11),':',HexStr(__end,11),':',HexStr(prot,2));
+       Writeln('pmap_enter_gpuobj:',HexStr(start,11),':',HexStr(__end,11),':',HexStr(offset,11),':',HexStr(prot,2));
       end;
 
       info.start:=start;
@@ -559,10 +569,16 @@ begin
        get_dmem_fd(info);
 
        delta:=(info.__end-info.start);
+       if (delta=0) then Break;
+
+       if (p_print_pmap<>0) then
+       begin
+        Writeln('vm_nt_map_insert:',HexStr(info.start,11),':',HexStr(info.__end,11),':',HexStr(info.offset,11));
+       end;
 
        r:=vm_nt_map_insert(@pmap^.nt_map,
                            info.obj,
-                           info.offset,
+                           info.offset and PMAPP_1GB_MASK, //block local offset
                            info.start,
                            info.__end,
                            delta,
@@ -596,7 +612,7 @@ begin
 
       r:=vm_nt_map_insert(@pmap^.nt_map,
                           info.obj,
-                          info.offset,
+                          info.offset, //one block for all dev
                           info.start,
                           info.__end,
                           delta,
@@ -677,6 +693,7 @@ begin
        get_private_fd(info);
 
        delta:=(info.__end-info.start);
+       if (delta=0) then Break;
 
        pmap_copy(pmap,
                  cow,
@@ -687,7 +704,7 @@ begin
 
        r:=vm_nt_map_insert(@pmap^.nt_map,
                            info.obj,
-                           0,
+                           0, //private always from the start
                            info.start,
                            info.__end,
                            delta,
@@ -717,7 +734,7 @@ begin
 
       r:=vm_nt_map_insert(@pmap^.nt_map,
                           info.obj,
-                          info.offset,
+                          info.offset, //offset in file
                           info.start,
                           info.__end,
                           size,