diff --git a/Docs/src/history.but b/Docs/src/history.but
index 522feccb..c9aa8bd5 100644
--- a/Docs/src/history.but
+++ b/Docs/src/history.but
@@ -20,9 +20,9 @@ Released on ??? ??rd, 20??
 
 \S2{} Minor Changes
 
-\b Added \R{intptrcmp}{IntPtrCmp}, IntPtrCmpU, Int64Cmp and Int64CmpU
+\b Added \R{intptrcmp}{IntPtrCmp}, IntPtrCmpU, and \R{intptrop}{IntPtrOp}
 
-\b Added \R{intptrop}{IntPtrOp}
+\b Added Int64Cmp, Int64CmpU and Int64Fmt (64-bit only)
 
 \b Added IntOp and System::Int64Op >>> operator
 
diff --git a/Docs/src/int.but b/Docs/src/int.but
index 57ac9964..b0f247e0 100644
--- a/Docs/src/int.but
+++ b/Docs/src/int.but
@@ -9,6 +9,16 @@ Formats the number in "numberstring" using the format "format", and sets the out
 \c IntFmt $0 "0x%08X" 195948557
 \c IntFmt $0 "%c" 0x41
 
+\S2{int64fmt} Int64Fmt
+
+\c user_var(output) format numberstring
+
+\NsisFuncReq64
+
+\c Int64Fmt $0 "%I64x" 244837743786702
+
+\# InternalNote: There is no IntPtrFmt instruction because "%p" is 2000+ and "%Ix" is XP+. Consequently, all code needs to check ${NSIS_PTR_SIZE}.
+
 \S2{intop} IntOp
 
 \c user_var(output) value1 OP [value2]
diff --git a/Source/exehead/exec.c b/Source/exehead/exec.c
index 1e0c27bb..c78708ef 100644
--- a/Source/exehead/exec.c
+++ b/Source/exehead/exec.c
@@ -683,7 +683,7 @@ static int NSISCALL ExecuteEntry(entry *entry_)
 #ifdef NSIS_SUPPORT_INTOPTS
     case EW_INTCMP:
       {
-        UINT supp64=sizeof(void*) > 4, opu=supp64 ? (BYTE) parm5 : parm5, op64=supp64 ? (INT16) parm5 < 0 : FALSE;
+        UINT supp64=sizeof(void*) > 4, opu=supp64 ? (BYTE) parm5 : parm5, op64=supp64 ? (SHORT) parm5 < 0 : FALSE;
         INT_PTR v=GetIntPtrFromParm(0), v2=GetIntPtrFromParm(1); // Note: This needs to be INT64 if supp64 is ever set to true for 32-bit builds!
         if (!opu) { // signed:
           if (op64) {
@@ -735,9 +735,8 @@ static int NSISCALL ExecuteEntry(entry *entry_)
     break;
     case EW_INTFMT: {
       TCHAR *buf0=GetStringFromParm(0x01);
-      wsprintf(var0,
-               buf0,
-               GetIntPtrFromParm(2)); // TODO: BUGBUG64: This sign-extends from INT32 to INT64, do we want that?
+      INT_PTR val=GetIntPtrFromParm(2), op64=sizeof(void*) > 4 && parm3;
+      wsprintf(var0,buf0,op64 ? val : (UINT)val);
     }
     break;
 #endif//NSIS_SUPPORT_INTOPTS
diff --git a/Source/exehead/fileform.h b/Source/exehead/fileform.h
index 22f09888..82de7923 100644
--- a/Source/exehead/fileform.h
+++ b/Source/exehead/fileform.h
@@ -98,7 +98,7 @@ enum
 #ifdef NSIS_SUPPORT_INTOPTS
   EW_INTCMP,            // IntCmp: 6 [val1, val2, equal, val1<val2, val1>val2, flags] where flags: bit 0x01 is set for unsigned operations and bit 0x8000 is set for 64-bit operations
   EW_INTOP,             // IntOp: 4 [output, input1, input2, op] where op: 0=add, 1=sub, 2=mul, 3=div, 4=bor, 5=band, 6=bxor, 7=bnot input1, 8=lor, 9=land 10=mod, 11=shl, 12=sar, 13=shr (bneg is implemented with bxor in compiler)
-  EW_INTFMT,            // IntFmt: [output, format, input]
+  EW_INTFMT,            // IntFmt: 4 [output, format, input, 64-bit]
 #endif
 #ifdef NSIS_SUPPORT_STACK
   EW_PUSHPOP,           // Push/Pop/Exchange: 3 [variable/string, ?pop:push, ?exch]
diff --git a/Source/exehead/util.c b/Source/exehead/util.c
index 1aa46f79..30ebaee0 100644
--- a/Source/exehead/util.c
+++ b/Source/exehead/util.c
@@ -507,7 +507,7 @@ HRESULT NSISCALL UTF16LEBOM(HANDLE h, INT_PTR ForWrite)
   if (0 == orgpos)
   {
     BYTE bom[2];
-    if (myReadFile(h, bom, 2) && (0xfeff == *(UINT16*) &bom[0]))
+    if (myReadFile(h, bom, 2) && (0xfeff == *(USHORT*) &bom[0]))
     {
       return S_OK;
     }
diff --git a/Source/script.cpp b/Source/script.cpp
index 183e79ab..8ecb747a 100644
--- a/Source/script.cpp
+++ b/Source/script.cpp
@@ -300,7 +300,7 @@ parse_again:
         ERROR_MSG(_T("Plugin%") NPRIs _T(" not found, cannot call %") NPRIs _T("\n"),m_pPlugins && m_pPlugins->IsKnownPlugin(tokstr0) ? _T(" function") : _T(""),tokstr0);
       else
 #endif
-        ERROR_MSG(_T("Invalid command: %") NPRIs _T("\n"),tokstr0);
+        ERROR_MSG(_T("Invalid command: \"%") NPRIs _T("\"\n"),tokstr0);
       return PS_ERROR;
     }
   }
@@ -4170,18 +4170,20 @@ int CEXEBuild::doCommand(int which_token, LineParser &line)
         SCRIPT_MSG(_T("%") NPRIs _T(": %") NPRIs _T("=%") NPRIs _T("%") NPRIs _T("%") NPRIs _T("\n"),cmdname,line.gettoken_str(1),line.gettoken_str(2),line.gettoken_str(3),line.gettoken_str(4));
       }
     return add_entry(&ent);
-    case TOK_INTFMT:
+    case TOK_INTFMT: case TOK_INT64FMT:
       ent.which=EW_INTFMT;
       ent.offsets[0]=GetUserVarIndex(line, 1);
       if (ent.offsets[0]<0) PRINTHELP()
       ent.offsets[1]=add_string(line.gettoken_str(2));
       ent.offsets[2]=add_string(line.gettoken_str(3));
+      ent.offsets[3]=which_token == TOK_INT64FMT;
+      if (ent.offsets[3] && !is_target_64bit()) return (ERROR_MSG(_T("%") NPRIns _T("\n"), "Instruction only supported by 64-bit targets!"), PS_ERROR);
       SCRIPT_MSG(_T("IntFmt: %") NPRIs _T("->%") NPRIs _T(" (fmt:%") NPRIs _T(")\n"),line.gettoken_str(3),line.gettoken_str(1),line.gettoken_str(2));
     return add_entry(&ent);
     case TOK_INTCMP: case TOK_INTCMPU: case TOK_INT64CMP: case TOK_INT64CMPU: case TOK_INTPTRCMP: case TOK_INTPTRCMPU:
       {
         int t64 = is_target_64bit(), o32 = TOK_INTCMP == which_token || TOK_INTCMPU == which_token, o64 = TOK_INT64CMP == which_token || TOK_INT64CMPU == which_token;
-        if (!t64 && o64) return (ERROR_MSG(_T("Instruction only supported by 64-bit targets!\n")), PS_ERROR);
+        if (!t64 && o64) return (ERROR_MSG(_T("%") NPRIns _T("\n"), "Instruction only supported by 64-bit targets!"), PS_ERROR);
         ent.which=EW_INTCMP;
         ent.offsets[0]=add_string(line.gettoken_str(1));
         ent.offsets[1]=add_string(line.gettoken_str(2));
@@ -4194,8 +4196,8 @@ int CEXEBuild::doCommand(int which_token, LineParser &line)
       }
 #else
     case TOK_INTOP: case TOK_INTPTROP:
+    case TOK_INTFMT: case TOK_INT64FMT:
     case TOK_INTCMP: case TOK_INTCMPU: case TOK_INT64CMP: case TOK_INT64CMPU: case TOK_INTPTRCMP: case TOK_INTPTRCMPU:
-    case TOK_INTFMT:
       ERROR_MSG(_T("Error: %") NPRIs _T(" specified, NSIS_SUPPORT_INTOPTS not defined.\n"),  line.gettoken_str(0));
       return PS_ERROR;
 #endif //~ NSIS_SUPPORT_INTOPTS
@@ -5113,7 +5115,7 @@ int CEXEBuild::doCommand(int which_token, LineParser &line)
     default:
       break;
   }
-  ERROR_MSG(_T("Error: doCommand: Invalid token \"%") NPRIs _T("\".\n"),line.gettoken_str(0));
+  ERROR_MSG(_T("Invalid command \"%") NPRIs _T("\"\n"),line.gettoken_str(0));
   return PS_ERROR;
 }
 
diff --git a/Source/tokens.cpp b/Source/tokens.cpp
index 1e89779c..a9735c76 100644
--- a/Source/tokens.cpp
+++ b/Source/tokens.cpp
@@ -131,6 +131,7 @@ static tokenType tokenlist[TOK__LAST] =
 {TOK_INTPTRCMP,_T("IntPtrCmp"),3,2,_T("val1 val2 jump_if_equal [jump_if_val1_less] [jump_if_val1_more]"),TP_CODE},
 {TOK_INTPTRCMPU,_T("IntPtrCmpU"),3,2,_T("val1 val2 jump_if_equal [jump_if_val1_less] [jump_if_val1_more]"),TP_CODE},
 {TOK_INTFMT,_T("IntFmt"),3,0,_T("$(user_var: output) format_string input"),TP_CODE},
+{TOK_INT64FMT,_T("Int64Fmt"),3,0,_T("$(user_var: output) format_string input"),TP_CODE},
 {TOK_ISWINDOW,_T("IsWindow"),2,1,_T("hwnd jump_if_window [jump_if_not_window]"),TP_CODE},
 {TOK_GOTO,_T("Goto"),1,0,_T("label"),TP_CODE},
 {TOK_LANGSTRING,_T("LangString"),3,0,_T("[un.]name lang_id|0 string"),TP_GLOBAL},
@@ -319,15 +320,15 @@ static tokenType tokenlist[TOK__LAST] =
 
 const TCHAR* CEXEBuild::get_commandtoken_name(int tok)
 {
-  for (int x = 0; x < TOK__LAST; ++x)
+  for (UINT x = 0; x < TOK__LAST; ++x)
     if (tokenlist[x].id==tok) return tokenlist[x].name;
   return 0;
 }
 
 void CEXEBuild::print_help(const TCHAR *commandname)
 {
-  int x;
-  for (x = 0; x < TOK__LAST; x ++)
+  UINT x;
+  for (x = 0; x < TOK__LAST; ++x)
   {
     if (!commandname || !_tcsicmp(tokenlist[x].name,commandname))
     {
@@ -376,7 +377,7 @@ bool CEXEBuild::is_unsafe_pp_token(int tkid)
 
 int CEXEBuild::get_commandtoken(const TCHAR *s, int *np, int *op, int *pos)
 {
-  for (int x = 0; x < TOK__LAST; x ++)
+  for (UINT x = 0; x < TOK__LAST; ++x)
     if (!_tcsicmp(tokenlist[x].name,s)) 
     {
       *np=tokenlist[x].num_parms;
diff --git a/Source/tokens.h b/Source/tokens.h
index 370cd81a..865c86e4 100644
--- a/Source/tokens.h
+++ b/Source/tokens.h
@@ -246,6 +246,7 @@ enum
   TOK_INTPTRCMP,
   TOK_INTPTRCMPU,
   TOK_INTFMT,
+  TOK_INT64FMT,
   TOK_ENUMREGKEY,
   TOK_ENUMREGVAL,
   TOK_PUSH,