From 90613a34bfe5a3e863306ce4edcaaa9ff1985a60 Mon Sep 17 00:00:00 2001
From: bixb922 <70152274+bixb922@users.noreply.github.com>
Date: Thu, 2 May 2024 09:29:57 -0400
Subject: [PATCH] Unary minus is being developed in version 1.23

---
 Improving-performance-with-Viper-code.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Improving-performance-with-Viper-code.md b/Improving-performance-with-Viper-code.md
index 1f32d9b..d731b58 100644
--- a/Improving-performance-with-Viper-code.md
+++ b/Improving-performance-with-Viper-code.md
@@ -234,6 +234,7 @@ A viper ```int``` is not an object, and thus does not support methods such as ``
 
 The \*\* operator (exponentiation, `__pow__`) is not implemented for viper ```int```.
 
+In versions MicroPython 1.22 and prior, unary minus is not implemented, instead of `x=-a` use `x=0-a`. In version 1.23 the unary minus is being implemented, but not completely yet.
 
 Be aware: Do not use shift left or right with a negative value, i.e. `x<<(-1)` or `x>>(-1)` should not be used because the result is undefined. This mirrors the C language definition for shifting. Unlike regular MicroPython, there is no check (no exception raised) for negative shift amounts.