diff --git a/sys/kern/kern_cpuset.pas b/sys/kern/kern_cpuset.pas
index 816bb982..61f6a194 100644
--- a/sys/kern/kern_cpuset.pas
+++ b/sys/kern/kern_cpuset.pas
@@ -21,8 +21,8 @@ function sys_cpuset_setaffinity(level,which:Integer;id,cpusetsize:QWORD;mask:p_c
 implementation
 
 uses
+ errno,
  systm,
- sys_kernel,
  kern_thread,
  vm_machdep;
 
diff --git a/sys/kern/kern_sig.pas b/sys/kern/kern_sig.pas
index 917d5ccc..622f9e18 100644
--- a/sys/kern/kern_sig.pas
+++ b/sys/kern/kern_sig.pas
@@ -7,7 +7,6 @@ interface
 
 uses
  gtailq,
- sys_kernel,
  time,
  signal,
  signalvar,
@@ -100,6 +99,7 @@ implementation
 
 uses
  ntapi,
+ errno,
  systm,
  kern_mtx,
  kern_time,
diff --git a/sys/kern/kern_thread.pas b/sys/kern/kern_thread.pas
index 501b7990..78411a5f 100644
--- a/sys/kern/kern_thread.pas
+++ b/sys/kern/kern_thread.pas
@@ -8,7 +8,6 @@ interface
 uses
  ntapi,
  windows,
- sys_kernel,
  ucontext,
  signal,
  signalvar,
@@ -239,6 +238,7 @@ implementation
 
 uses
  gtailq,
+ errno,
  systm,
  vm_machdep,
  kern_rwlock,
diff --git a/sys/kern/kern_time.pas b/sys/kern/kern_time.pas
index 9e2d751d..f2277f5f 100644
--- a/sys/kern/kern_time.pas
+++ b/sys/kern/kern_time.pas
@@ -6,7 +6,6 @@ unit kern_time;
 interface
 
 uses
- sys_kernel,
  windows,
  ntapi,
  time;
@@ -21,6 +20,9 @@ function kern_clock_getres(clock_id:Integer;tp:Ptimespec):Integer;
 
 implementation
 
+uses
+ errno;
+
 Const
  UNIT_PER_SEC         =10000000;
  DELTA_EPOCH_IN_UNIT  =116444736000000000;
diff --git a/sys/kern/kern_umtx.pas b/sys/kern/kern_umtx.pas
index 2b9a7724..c8152307 100644
--- a/sys/kern/kern_umtx.pas
+++ b/sys/kern/kern_umtx.pas
@@ -10,10 +10,8 @@ uses
  kern_rwlock,
  time,
  kern_time,
-
  kern_thread,
- _umtx,
- sys_kernel;
+ _umtx;
 
 procedure _umutex_init(mtx:p_umutex); inline;
 
@@ -35,6 +33,7 @@ implementation
 
 uses
  HAMT,
+ errno,
  systm,
  trap,
  vm_machdep;
diff --git a/sys/kern/machdep.pas b/sys/kern/machdep.pas
index d4f992a2..967b6207 100644
--- a/sys/kern/machdep.pas
+++ b/sys/kern/machdep.pas
@@ -9,8 +9,7 @@ uses
  signal,
  signalvar,
  ucontext,
- kern_thread,
- sys_kernel;
+ kern_thread;
 
 const
  _ucodesel=(8 shl 3) or 3;
@@ -24,6 +23,7 @@ function  sys_sigreturn(sigcntxp:p_ucontext_t):Integer;
 implementation
 
 uses
+ errno,
  systm,
  md_psl,
  kern_sig,
diff --git a/sys/kern/trap.pas b/sys/kern/trap.pas
index 4ffeaa64..e69dce73 100644
--- a/sys/kern/trap.pas
+++ b/sys/kern/trap.pas
@@ -258,6 +258,7 @@ procedure fast_syscall; assembler; nostackframe;
 label
  _after_call,
  _doreti,
+ _fail,
  _ast,
  _doreti_exit;
 asm
@@ -265,11 +266,18 @@ asm
  pushq %rbp
  movq  %rsp,%rbp
 
- lock orl SIG_STI_LOCK,%gs:teb.iflag //lock interrupt
+ movqq %rax,-16(%rsp) //save rax
 
- movqq %rax,-16(%rsp)  //save rax
+ lahf //load to AH
+ shr   $8,%rax
+ andl  $0xFF,%rax //filter
+ movqq %rax,-8(%rsp) //save flags
 
  movqq %gs:teb.thread,%rax //curkthread
+ test  %rax,%rax
+ jz    _fail
+
+ lock orl SIG_STI_LOCK,%gs:teb.iflag //lock interrupt
 
  andl  NOT_PCB_FULL_IRET,kthread.pcb_flags(%rax) //clear PCB_FULL_IRET
 
@@ -307,12 +315,13 @@ asm
  movqq -16(%rsp),%r11 //get rax
  movqq %r11,trapframe.tf_rax(%rax)
 
- pushfq     //push FLAGS
- popq  %r11 //get  FLAGS
+ movqq -8(%rsp),%r11 //get flags
  movqq %r11,trapframe.tf_rflags(%rax)
 
  movqq %gs:teb.thread,%rsp          //curkthread
- movqq kthread.td_kstack(%rsp),%rsp //td_kstack
+ movqq kthread.td_kstack(%rsp),%rsp //td_kstack (Implicit lock interrupt)
+
+ lock andl NOT_SIG_STI_LOCK,%gs:teb.iflag //unlock interrupt
 
  andq $-32,%rsp //align stack
 
@@ -329,29 +338,44 @@ asm
  testl TDF_AST,kthread.td_flags(%rax)
  jne _ast
 
- movqq %gs:teb.thread,%rax         //curkthread
- movqq kthread.td_frame(%rax),%rax //td_frame
+ movqq %gs:teb.thread,%rcx         //curkthread
+ movqq kthread.td_frame(%rcx),%rcx //td_frame
 
  //Restore preserved registers.
- movqq trapframe.tf_rflags(%rax),%r11
- pushq %r11 //set FLAGS
- popfq      //pop FLAGS
+ movqq trapframe.tf_rflags(%rcx),%rax
+ shl   $8,%rax
+ sahf  //restore flags
 
- movqq trapframe.tf_rdi(%rax),%rdi
- movqq trapframe.tf_rsi(%rax),%rsi
- movqq trapframe.tf_rdx(%rax),%rdx
+ movqq trapframe.tf_rdi(%rcx),%rdi
+ movqq trapframe.tf_rsi(%rcx),%rsi
+ movqq trapframe.tf_rdx(%rcx),%rdx
+ movqq trapframe.tf_rax(%rcx),%rax
 
- movqq trapframe.tf_rsp(%rax),%rsp
- lea  -16(%rsp),%rsp //restore rsp
+ movqq trapframe.tf_rsp(%rcx),%r11
+ lea  -16(%r11),%r11
 
- movqq trapframe.tf_rax(%rax),%rax //restore rax
+ movqq %r11,%rsp //restore rsp (Implicit unlock interrupt)
 
- lock andl NOT_SIG_STI_LOCK,%gs:teb.iflag //unlock interrupt
+ movqq $0,%rcx
+ movqq $0,%r11
 
  //epilog (debugger)
  popq  %rbp
  ret
 
+ //fail:
+ _fail:
+
+ movqq -8(%rsp),%rax //get flags
+ shl   $8,%rax
+ or    $1,%ah //CF
+ sahf  //restore flags
+
+ movqq $14,%rax //EFAULT
+
+ popq  %rbp
+ ret
+
  //ast
  _ast:
 
@@ -371,9 +395,7 @@ asm
  _doreti_exit:
 
   //Restore full.
-  xor   %rdi,%rdi
-  inc   %rdi
-  call  ipi_sigreturn //1
+  call  ipi_sigreturn
   hlt
 end;
 
@@ -406,8 +428,7 @@ asm
   jmp _ast
 
  _ast_exit:
-  xor   %rdi,%rdi
-  call  ipi_sigreturn //0
+  call  ipi_sigreturn
   hlt
 end;
 
diff --git a/sys/kern/vm_machdep.pas b/sys/kern/vm_machdep.pas
index 338c9926..1ea19e0c 100644
--- a/sys/kern/vm_machdep.pas
+++ b/sys/kern/vm_machdep.pas
@@ -11,7 +11,6 @@ uses
  md_psl,
  ucontext,
  trap,
- sys_kernel,
  kern_thread;
 
 var
@@ -27,7 +26,7 @@ procedure cpu_set_user_tls(td:p_kthread;base:Pointer);
 function  cpu_set_priority(td:p_kthread;prio:Integer):Integer;
 function  cpu_getstack(td:p_kthread):QWORD;
 
-procedure ipi_sigreturn(unlock:Integer);
+procedure ipi_sigreturn;
 function  ipi_send_cpu(td:p_kthread):Integer;
 
 function  _umtxq_alloc:THandle; inline;
@@ -41,6 +40,7 @@ function  wakeup_td(td:p_kthread):Integer; inline;
 implementation
 
 uses
+ errno,
  systm,
  machdep,
  signal,
@@ -248,7 +248,7 @@ begin
  end;
 end;
 
-procedure ipi_sigreturn(unlock:Integer);
+procedure ipi_sigreturn;
 var
  _Context:array[0..SizeOf(TCONTEXT)+14] of Byte;
  Context :PCONTEXT;
@@ -287,11 +287,6 @@ begin
  Context^.SegSs:=KGDT64_R3_DATA  or RPL_MASK;
  Context^.SegFs:=KGDT64_R3_CMTEB or RPL_MASK;
 
- if (unlock<>0) then
- begin
-  sig_cli;
- end;
-
  NtContinue(Context,False);
 end;
 
@@ -364,7 +359,7 @@ begin
  begin
   NtResumeThread(td_handle,nil);
   w.QuadPart:=-10000;
-  SwDelayExecution(False,@w); //100ms
+  NtDelayExecution(False,@w); //100ms
   goto tryagain;
  end;
 
diff --git a/sys/sys_umtx.pas b/sys/sys_umtx.pas
index 36a969a3..badd57ae 100644
--- a/sys/sys_umtx.pas
+++ b/sys/sys_umtx.pas
@@ -6,7 +6,7 @@ unit sys_umtx;
 interface
 
 uses
- sys_kernel,
+ errno,
  time,
  _umtx;
 
diff --git a/sys/test/project1.lpr b/sys/test/project1.lpr
index e2ca2d42..0738636b 100644
--- a/sys/test/project1.lpr
+++ b/sys/test/project1.lpr
@@ -175,18 +175,19 @@ begin
 
   sigaction(SIGUSR1,@act,nil,0);
 
-  //thr_kill(tid,SIGUSR1);
-  thr_wake(tid);
+  thr_kill(tid,SIGUSR1);
+  //thr_wake(tid);
  end else
  begin
-  Writeln('thr_suspend:',thr_suspend(nil));
+  //Writeln('thr_suspend:',thr_suspend(nil));
+
   {
   oset.qwords[0]:=QWORD(-1);
   oset.qwords[1]:=QWORD(-1);
   Writeln('sigwait:',sigwait(@oset,@_sig));
   Writeln('intr:',_sig);
   }
-  {
+
   Writeln('before: sptr:',HexStr(sptr));
   repeat
    asm
@@ -195,7 +196,6 @@ begin
   until (intr<>0);
   Writeln('intr');
   Writeln('after: sptr:',HexStr(sptr));
-  }
  end;
 
  sig_lock;
@@ -612,6 +612,9 @@ var
 begin
  //test_map;
 
+ e:=_umtx_op(nil,UMTX_OP_RW_WRLOCK,0,nil,nil);
+ Writeln('me=',e);
+
  kern_clock_gettime_unit(CLOCK_PROCTIME,@_time);
  writeln(_time/10000000:0:3);