diff --git a/Contrib/System/Source/Call-amd64.S b/Contrib/System/Source/Call-amd64.S
index eccb3dcb..3cdfd576 100644
--- a/Contrib/System/Source/Call-amd64.S
+++ b/Contrib/System/Source/Call-amd64.S
@@ -62,19 +62,15 @@ IF 0
 ENDIF
 
 
-EXTERN __imp_GetLastError : PROC
 IFDEF SYSTEM_LOG_DEBUG
   EXTERN __imp_IsDebuggerPresent : PROC
 ENDIF
 
-EXTERN LastError : DWORD
-
 EXTERN GetProcOffset       : PROC
 EXTERN GetParamsOffset     : PROC
 EXTERN GetSizeOfProcParam  : PROC
 EXTERN GetValueOffsetParam : PROC
-EXTERN SetProcResultOk     : PROC
-EXTERN GetErrorOption      : PROC
+EXTERN SetCallProcResultValues   : PROC
 
 
 SECTION_CODE
@@ -161,27 +157,11 @@ callthefunc:
   mov r10, qword ptr [pSystemProc+rax]
   xor rax, rax ;# Fix bug #1535007
   call r10
-  mov r13, rax ;# Save return value
-
   mov rcx, pSystemProc
-  call GetErrorOption
-  test eax, eax
-  jz capturegle_done
-  call qword ptr [__imp_GetLastError]
-  mov dword ptr [LastError], eax
-capturegle_done:
+  mov rdx, rax ;# Return value
+  call SetCallProcResultValues ;# Store GetLastError() and return value
+  ;# mov rax, pSystemProc has been performed by SetCallProcResultValues
 
-  ;# proc->Params[0].Value = pSystemProc->Proc's return value
-  call GetParamsOffset
-  mov rdx, rax ;# This assumes that the next function is not going to clobber rdx!
-  call GetValueOffsetParam
-  add rdx, rax
-  mov qword ptr [pSystemProc+rdx], r13
-
-  mov rcx, pSystemProc
-  call SetProcResultOk ;# BUGBUG: This is pointless, system.c should just assume we are OK
-
-  mov rax, pSystemProc ;# Return SystemProc*
   ;# Epilog:
   ;# http://msdn.microsoft.com/en-us/library/tawsa7cb claims that only 
   ;# add/lea rsp and pop is valid in the epilog. Unwind might fail on our version?
diff --git a/Contrib/System/Source/Call.S b/Contrib/System/Source/Call.S
index ec42dc2b..28aa04ca 100644
--- a/Contrib/System/Source/Call.S
+++ b/Contrib/System/Source/Call.S
@@ -146,7 +146,6 @@ ENDIF
 EXTERN    __alloca_probe         : PROC
 
 EXTERN    __imp__GlobalFree@4    : PROC
-EXTERN    __imp__GetLastError@0  : PROC
 
 IFDEF _UNICODE
 EXTERN    __imp__wsprintfW       : PROC
@@ -158,7 +157,6 @@ EXTERN    _GlobalCopy            : PROC
 
 EXTERN    _LastStackPlace        : DWORD
 EXTERN    _LastStackReal         : DWORD
-EXTERN    _LastError             : DWORD
 EXTERN    _LastProc              : DWORD
 EXTERN    _CallbackIndex         : DWORD
 
@@ -168,7 +166,6 @@ EXTERN    _retaddr               : PTR
 EXTERN    _GetNewStackSize       : PROC
 EXTERN    _GetGenStackOption     : PROC
 EXTERN    _GetCDeclOption        : PROC
-EXTERN    _GetErrorOption        : PROC
 EXTERN    _GetProcOffset         : PROC
 EXTERN    _GetCloneOffset        : PROC
 EXTERN    _GetProcNameOffset     : PROC
@@ -180,7 +177,7 @@ EXTERN    _GetSizeOffsetParam    : PROC
 EXTERN    _GetValueOffsetParam   : PROC
 EXTERN    _Get_valueOffsetParam  : PROC
 EXTERN    _SetCloneOption        : PROC
-EXTERN    _SetProcResultOk       : PROC
+EXTERN    _SetCallProcResultValues@12  : PROC
 EXTERN    _SetProcResultCallback : PROC
 
 SECTION_DATA
@@ -566,7 +563,7 @@ params_loop_done:
   ;# Call
   call        ecx
 
-  ;# Return
+  ;# Save return
   mov         dword ptr [_z1],eax
   mov         dword ptr [_z2],edx
 
@@ -707,34 +704,11 @@ stack_clear_done:
 stack_cleanup_done:
 
   ;# Save return
-
-  ;# Get offset for element Params of SystemProc structure
-  call        _GetParamsOffset
-  mov         edx,dword ptr [ebp+8]
-  add         edx,eax
-
-  ;# proc->Params[0].Value = Low double word of result
-  call        _GetValueOffsetParam
-  mov         ecx,dword ptr [_z1]
-  mov         dword ptr [edx+eax],ecx
-
-  ;# proc->Params[0]._value = High double word of result
-  call        _Get_valueOffsetParam
-  mov         ecx,dword ptr [_z2]
-  mov         dword ptr [edx+eax],ecx
-
-  ;# Proc result: OK
+  push        dword ptr [_z2]
+  push        dword ptr [_z1]
   push        dword ptr [ebp+8]
-  call        _SetProcResultOk
-  ;# In case of POPT_ERROR -> Get_LastError
-  call        _GetErrorOption
-  cmp         eax,0
-  pop         eax
-  je          handling_error_option_done
-  call        dword ptr [__imp__GetLastError@0]
-  mov         dword ptr [_LastError],eax
+  call        _SetCallProcResultValues@12
 
-handling_error_option_done:
   IFDEF SYSTEM_LOG_DEBUG
     SYSTEM_EVENT offset LogAfterCall
 
diff --git a/Contrib/System/Source/System.c b/Contrib/System/Source/System.c
index 99754c7d..dce1a097 100644
--- a/Contrib/System/Source/System.c
+++ b/Contrib/System/Source/System.c
@@ -68,11 +68,7 @@ HANDLE retaddr;
 
 static TCHAR *MakeResultStr(SystemProc *proc, TCHAR *buf)
 {
-    if (proc->ProcResult == PR_OK)
-        lstrcpy(buf, _T("ok"));
-    else if (proc->ProcResult == PR_ERROR)
-        lstrcpy(buf, _T("error"));
-    else if (proc->ProcResult == PR_CALLBACK)
+    if (proc->ProcResult == PR_CALLBACK)
     {
         INT_PTR id = proc->CallbackIndex;
 #ifdef POPT_SYNTAX2
@@ -81,6 +77,13 @@ static TCHAR *MakeResultStr(SystemProc *proc, TCHAR *buf)
 #endif
         wsprintf(buf, sizeof(void*) > 4 ? _T("callback%Id") : _T("callback%d"), id); // "%d" must match format used by system_pushintptr() in Get() because script will StrCmp!
     }
+    else
+    {
+        const TCHAR *resstr = _T("error");
+        if (proc->ProcResult == PR_OK)
+            resstr = _T("ok");
+        lstrcpy(buf, resstr);
+    }
     return buf;
 }
 
@@ -1437,7 +1440,7 @@ unsigned int GetCDeclOption(SystemProc *proc)
 /*
 Returns non-zero value if Error option is set
 */
-unsigned int GetErrorOption(SystemProc *proc)
+static unsigned int GetErrorOption(SystemProc *proc)
 {
     return (proc->Options & POPT_ERROR);
 }
@@ -1535,7 +1538,7 @@ void SetCloneOption(SystemProc *proc)
 /*
 Sets Result of procedure call to be "OK"
 */
-void SetProcResultOk(SystemProc *proc)
+static void SetProcResultOk(SystemProc *proc)
 {
     proc->ProcResult = PR_OK;
 }
@@ -1547,3 +1550,15 @@ void SetProcResultCallback(SystemProc *proc)
 {
     proc->ProcResult = PR_CALLBACK;
 }
+
+SystemProc* CALLBACK SetCallProcResultValues(SystemProc *proc, ULARGE_INTEGER retval)
+{
+    if (GetErrorOption(proc)) LastError = GetLastError();
+#ifdef _WIN64
+    proc->Params[0].Value = retval.QuadPart;
+#else
+    proc->Params[0].Value = retval.LowPart, proc->Params[0]._value = retval.HighPart;
+#endif
+    SetProcResultOk(proc);
+    return proc;
+}