Relaxing the makefile for older processors and updating the README wi…

…th hardware requirements.

README.md

@@ -19,13 +19,20 @@ http://arxiv.org/abs/1209.2137
 
 This code is licensed under Apache License, Version 2.0 (ASL2.0).
 
-## Requirements
+## Software Requirements
 
 This code requires a (recent as of 2012) compiler supporting C++11. This was
 a design decision.
 It builds under both clang++ 3.2 (LLVM 3.2) and GCC 4.7.
 The code was tested under Linux and MacOS.
 
+## Hardware Requirements
+
+Your processor should support SSSE3. This includes almost every Intel or AMD processor
+sold after 2006.
+
+Some specific binaries will only run if your processor supports SSE4.1. 
+
 ## Building with CMake
 
 At the root of the project:

makefile

@@ -7,7 +7,7 @@ YOURCXX ?= g++-4.7
 CXX := $(YOURCXX)
 
 # todo: allow custom architectures , e.g., -march=nocona -march=corei7
-CXXFLAGSEXTRA = -mssse3 -msse4.1 # mssse3 necessary for varintg8iu and msse4.1 necessary for horizontal bit packing
+CXXFLAGSEXTRA = -mssse3 # mssse3 necessary for varintg8iu and msse4.1 necessary for horizontal bit packing
 CXXFLAGS = $(CXXFLAGSEXTRA)  -std=c++0x -Weffc++ -pedantic -O3 -Wold-style-cast -Wall -Wextra -Wcast-align -Wunsafe-loop-optimizations -Wcast-qual
 #-ggdb
 
@@ -53,7 +53,7 @@ gapstats: $(HEADERS) src/gapstats.cpp
 	$(CXX) $(CXXFLAGS) -o gapstats src/gapstats.cpp -Iheaders
 
 benchbitpacking: $(HEADERS) src/benchbitpacking.cpp ./headers/rolledbitpacking.h ./headers/common.h.gch makefile $(COMMONBINARIES) horizontalbitpacking.o
-	$(CXX) $(CXXFLAGS) $(GCCPARAMS) -Winvalid-pch  -o benchbitpacking src/benchbitpacking.cpp $(COMMONBINARIES) horizontalbitpacking.o -Iheaders
+	$(CXX) $(CXXFLAGS) $(GCCPARAMS) -msse4.1  -Winvalid-pch  -o benchbitpacking src/benchbitpacking.cpp $(COMMONBINARIES) horizontalbitpacking.o -Iheaders
 
 partitionbylength: $(HEADERS) src/partitionbylength.cpp
 	$(CXX) $(CXXFLAGS) -o partitionbylength src/partitionbylength.cpp -Iheaders