Index: src/printf.c
==================================================================
--- src/printf.c
+++ src/printf.c
@@ -409,16 +409,15 @@
 #endif
         if( infop->type==etFLOAT ) realvalue += rounder;
         /* Normalize realvalue to within 10.0 > realvalue >= 1.0 */
         exp = 0;
         if( realvalue>0.0 ){
-          int k = 0;
-          while( realvalue>=1e8 && k++<100 ){ realvalue *= 1e-8; exp+=8; }
-          while( realvalue>=10.0 && k++<100 ){ realvalue *= 0.1; exp++; }
-          while( realvalue<1e-8 && k++<100 ){ realvalue *= 1e8; exp-=8; }
-          while( realvalue<1.0 && k++<100 ){ realvalue *= 10.0; exp--; }
-          if( k>=100 ){
+          while( realvalue>=1e8 && exp<=350 ){ realvalue *= 1e-8; exp+=8; }
+          while( realvalue>=10.0 && exp<=350 ){ realvalue *= 0.1; exp++; }
+          while( realvalue<1e-8 && exp>=-350 ){ realvalue *= 1e8; exp-=8; }
+          while( realvalue<1.0 && exp>=-350 ){ realvalue *= 10.0; exp--; }
+          if( exp>350 || exp<-350 ){
             bufpt = "NaN";
             length = 3;
             break;
           }
         }

Index: src/test1.c
==================================================================
--- src/test1.c
+++ src/test1.c
@@ -11,11 +11,11 @@
 *************************************************************************
 ** Code for testing the printf() interface to SQLite.  This code
 ** is not included in the SQLite library.  It is used for automated
 ** testing of the SQLite library.
 **
-** $Id: test1.c,v 1.34 2004/02/21 19:02:30 drh Exp $
+** $Id: test1.c,v 1.35 2004/02/21 19:41:04 drh Exp $
 */
 #include "sqliteInt.h"
 #include "tcl.h"
 #include "os.h"
 #include <stdlib.h>
@@ -529,10 +529,40 @@
   z = sqlite_mprintf(argv[1], a[0], a[1], r);
   Tcl_AppendResult(interp, z, 0);
   sqlite_freemem(z);
   return TCL_OK;
 }
+
+/*
+** Usage:  sqlite_mprintf_str FORMAT DOUBLE DOUBLE
+**
+** Call mprintf with a single double argument which is the product of the
+** two arguments given above.  This is used to generate overflow and underflow
+** doubles to test that they are converted properly.
+*/
+static int sqlite_mprintf_scaled(
+  void *NotUsed,
+  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
+  int argc,              /* Number of arguments */
+  char **argv            /* Text of each argument */
+){
+  int i;
+  double r[2];
+  char *z;
+  if( argc!=4 ){
+    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
+       " FORMAT DOUBLE DOUBLE\"", 0);
+    return TCL_ERROR;
+  }
+  for(i=2; i<4; i++){
+    if( Tcl_GetDouble(interp, argv[i], &r[i-2]) ) return TCL_ERROR;
+  }
+  z = sqlite_mprintf(argv[1], r[0]*r[1]);
+  Tcl_AppendResult(interp, z, 0);
+  sqlite_freemem(z);
+  return TCL_OK;
+}
 
 /*
 ** Usage: sqlite_malloc_fail N
 **
 ** Rig sqliteMalloc() to fail on the N-th call.  Turn off this mechanism
@@ -950,10 +980,11 @@
      Tcl_CmdProc *xProc;
   } aCmd[] = {
      { "sqlite_mprintf_int",             (Tcl_CmdProc*)sqlite_mprintf_int    },
      { "sqlite_mprintf_str",             (Tcl_CmdProc*)sqlite_mprintf_str    },
      { "sqlite_mprintf_double",          (Tcl_CmdProc*)sqlite_mprintf_double },
+     { "sqlite_mprintf_scaled",          (Tcl_CmdProc*)sqlite_mprintf_scaled },
      { "sqlite_mprintf_z_test",          (Tcl_CmdProc*)test_mprintf_z        },
      { "sqlite_open",                    (Tcl_CmdProc*)sqlite_test_open      },
      { "sqlite_last_insert_rowid",       (Tcl_CmdProc*)test_last_rowid       },
      { "sqlite_exec_printf",             (Tcl_CmdProc*)test_exec_printf      },
      { "sqlite_get_table_printf",        (Tcl_CmdProc*)test_get_table_printf },

Index: test/printf.test
==================================================================
--- test/printf.test
+++ test/printf.test
@@ -9,11 +9,11 @@
 #
 #***********************************************************************
 # This file implements regression tests for SQLite library.  The
 # focus of this file is testing the sqlite_*_printf() interface.
 #
-# $Id: printf.test,v 1.7 2004/02/02 12:29:25 drh Exp $
+# $Id: printf.test,v 1.8 2004/02/21 19:41:05 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
 
 set n 1
@@ -110,6 +110,17 @@
 
 do_test printf-6.1 {
   sqlite_mprintf_z_test , one two three four five six
 } {,one,two,three,four,five,six}
 
+
+do_test printf-7.1 {
+  sqlite_mprintf_scaled {A double: %g} 1.0e307 1.0
+} {A double: 1e+307}
+do_test printf-7.2 {
+  sqlite_mprintf_scaled {A double: %g} 1.0e307 10.0
+} {A double: 1e+308}
+do_test printf-7.3 {
+  sqlite_mprintf_scaled {A double: %g} 1.0e307 100.0
+} {A double: NaN}
+
 finish_test