From c9440c9249a9095c902432df28854d46303f21d5 Mon Sep 17 00:00:00 2001
From: "Daniel A. Maierhofer" <git@damadmai.at>
Date: Fri, 6 Feb 2015 12:21:13 +0100
Subject: [PATCH] Save program space by calculating CTLbyte instead of fixed
 literal

by https://github.com/vmire/Arduino_lib_RFM69/commit/fca63f659dd5eb775b30fb1cf8b9f0fd44b56bd5
---
 RFM69.cpp | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/RFM69.cpp b/RFM69.cpp
index 4579516..b63b00c 100644
--- a/RFM69.cpp
+++ b/RFM69.cpp
@@ -264,19 +264,20 @@ void RFM69::sendFrame(uint8_t toAddress, const void* buffer, uint8_t bufferSize,
   writeReg(REG_DIOMAPPING1, RF_DIOMAPPING1_DIO0_00); // DIO0 is "Packet Sent"
   if (bufferSize > RF69_MAX_DATA_LEN) bufferSize = RF69_MAX_DATA_LEN;
 
+  // control byte
+  uint8_t CTLbyte = 0x00;
+  if (sendACK)
+    CTLbyte = 0x80;
+  else if (requestACK)
+    CTLbyte = 0x40;
+
   // write to FIFO
   select();
   SPI.transfer(REG_FIFO | 0x80);
   SPI.transfer(bufferSize + 3);
   SPI.transfer(toAddress);
   SPI.transfer(_address);
-
-  // control byte
-  if (sendACK)
-    SPI.transfer(0x80);
-  else if (requestACK)
-    SPI.transfer(0x40);
-  else SPI.transfer(0x00);
+  SPI.transfer(CTLbyte);
 
   for (uint8_t i = 0; i < bufferSize; i++)
     SPI.transfer(((uint8_t*) buffer)[i]);