Corrected small int/viper signed int range to -2**29 to 2**29-1

Improving-performance-with-Viper-code.md

@@ -116,7 +116,7 @@ A viper `int` is different to the ```int``` we know in MicroPython, which is sti
 It is advisable to be aware at all times that `viper int` and `builtins.int` are different data types.
 
 ### Viper integer constants
-Viper integer constants are in the range -2\*\*30 to 2\*\*30-1. When you assign a viper constant to a variable, it automatically is a viper `int`.
+Viper integer constants are in the range -2\*\*29 to 2\*\*29-1. When you assign a viper constant to a variable, it automatically is a viper `int`.
 
 Be aware: integer constants don't have the full range of values a viper int value can hold, they are signed 31 bit integers. 
 
@@ -133,7 +133,7 @@ As it is usual in Python, a viper variable is of type viper `int when  you assig
 ```
 If the variable is created by assigning an expression, the viper code emitter will evaluate the expression at compile time.
 
-Be aware: Integer expressions outside what is called the "small integer" range of MicroPython are not viper `int` but `builtins.int`.  On most architectures a MicroPython small integer falls is -2\*\*30-1 and 2\*\*30-1. 
+Be aware: Integer expressions outside what is called the "small integer" range of MicroPython are not viper `int` but `builtins.int`.  On most architectures a MicroPython small integer falls is -2\*\*29 and 2\*\*29-1. 
 
 For example:
 ```py
@@ -156,7 +156,7 @@ With the type hint, `x` is converted on the fly to the viper `int` data type usi
 
 ## Making sure a viper int is a viper int
 
-There is a possible source of problems: when you initialize a viper `int` with a integer expression that falls outside of the signed 30 bit range (not the 32 bit range!), a `builtins.int` will be created instead, no warning. The same happens if you try initialize a viper int with a variable of type `builtins.int`. These errors can go unnoticed.
+There is a possible source of problems: when you initialize a viper `int` with a integer expression that falls outside of the viper int range (which is not the 32 bit range!), a `builtins.int` will be created instead, no warning. The same happens if you try initialize a viper int with a variable of type `builtins.int`. These errors can go unnoticed.
 
 Solution: Except for very short viper functions, you could initialize all viper `int` variables at the beginning setting them to zero (just as you might do in C language):
 ```py