Merge pull request #15 from psteinb/multi_feature_query

Multi feature query

README.md

@@ -9,7 +9,7 @@ A drop-in header-only C++ library to detect hardware capabilities at runtime and
 
 You have 2 options:
 
-1. you can just copy the contents of `include` into your project and off you go
+1. you can just copy the contents of `single_include` (or `include` if you like to have multiple folders and source code files)  into your project and off you go
 
 2. you use the cmake build infrastructure to put compass in a desired folder
 
@@ -22,17 +22,17 @@ You have 2 options:
     $ make install #depending on the contents of CMAKE_INSTALL_PREFIX, you may use sudo
     ```
 
-    - on Windows platforms (assuming that `cmake` and `boost\lib` are in your `PATH`)
+    - on Windows platforms (assuming that `cmake` is in your `PATH`)
 	```
 	> cd repo
 	> mkdir build
 	> cd build
-	> cmake.exe -G "Visual Studio 14 2015 Win64" -DBOOST_ROOT=C:\path\to\boost\1_59_0 ..
+	> cmake.exe -G "Visual Studio 14 2015 Win64" ..
 	> cmake.exe --build . --target ALL_BUILD --config Release
 	> ctest.exe -C Release
 	```
 
-(3.) tests can only be run if you have access to the test machines and it requires boost to be installed (if boost is not detected, the tests are skipped and a warning is issued)
+(3.) tests should only be run on the hardware where `cmake` was called. `CMakeLists.txt` is trying hard to detect the hardware features at `cmake` invocation. They are then included in the unit test suite. 
 
 ## Compass API
 
@@ -65,14 +65,13 @@ This project is quite small, so here is your chance to boost open-source to the
 
 - [ ] code review the model to extend compass for new compilers/platforms/OSes
 - [ ] code review the model to extend compass for new features
-- [ ] contribute adding detection of the cache hierarchy and associated cache sizes on x86 
 - [ ] is thread-safety an issue of the current implementation ?
 - [ ] contribute for adding Intel compiler on x86
 - [ ] contribute for GPUs (nvcc)
 - [ ] extend support for OpenPower (gcc)
 - [ ] contribute for ARM (gcc/clang) if you have according hardware available
 
-A good place to start and to see what is needed, is llvm [`Host.cpp`](http://llvm.org/docs/doxygen/html/Host_8cpp_source.html) file
+A good place to start and to see what is needed, is llvm [`Host.cpp`](http://llvm.org/docs/doxygen/html/Host_8cpp_source.html) file.
 
 ## License
 

include/detail/api.hpp

@@ -58,6 +58,40 @@ namespace compass {
 
         }
 
+
+        namespace detail {
+
+            static std::uint32_t accumulate(std::uint32_t value){
+                return value;
+            }
+
+            template < typename T, typename... features_t >
+            static std::uint32_t accumulate(std::uint32_t value,
+                                        T head,
+                                        features_t... tail)
+            {
+
+                std::uint32_t local = compass::runtime::has(head);
+                value = (value <<= 1) | local;
+
+                return accumulate(value,tail...);
+
+            }
+
+        };
+
+
+        template <typename... feature_t>
+        static std::uint32_t accumulate(feature_t... features) {
+
+            static const int pack_size = sizeof...(features);
+            static_assert(pack_size <= 32, "[compass::runtime::accumulate] unable to handle more than 32 features" );
+
+            std::uint32_t value = compass::runtime::detail::accumulate( 0u, features...);
+            return value;
+
+        }
+
         namespace size {
 
             struct cacheline{

single_include/compass.hpp

@@ -1116,6 +1116,40 @@ namespace compass {
 
         }
 
+
+        namespace detail {
+
+            static std::uint32_t accumulate(std::uint32_t value){
+                return value;
+            }
+
+            template < typename T, typename... features_t >
+            static std::uint32_t accumulate(std::uint32_t value,
+                                        T head,
+                                        features_t... tail)
+            {
+
+                std::uint32_t local = compass::runtime::has(head);
+                value = (value <<= 1) | local;
+
+                return accumulate(value,tail...);
+
+            }
+
+        };
+
+
+        template <typename... feature_t>
+        static std::uint32_t accumulate(feature_t... features) {
+
+            static const int pack_size = sizeof...(features);
+            static_assert(pack_size <= 32, "[compass::runtime::accumulate] unable to handle more than 32 features" );
+
+            std::uint32_t value = compass::runtime::detail::accumulate( 0u, features...);
+            return value;
+
+        }
+
         namespace size {
 
             struct cacheline{

tests/test_build_machine.cpp

@@ -3,6 +3,7 @@
 
 #include "compass.hpp"
 
+#include <bitset>
 #include <vector>
 #include <iostream>
 #include <string>
@@ -115,6 +116,20 @@ TEST_CASE_METHOD( host_reference, "machine_specific" ){
 
   }
 
+  SECTION( "has_multiple_features" ){
+
+    auto value = compass::runtime::accumulate(compass::feature::avx(),compass::feature::sse4(),compass::feature::sse3());
+
+    const bool expected = (expected_has_avx || expected_has_sse4 || expected_has_sse3 );
+    REQUIRE(bool(value) == expected );
+    std::bitset<3> mask((unsigned long)value);
+
+    REQUIRE(mask[0] ==  expected_has_avx);
+    REQUIRE(mask[1] ==  expected_has_sse4);
+    REQUIRE(mask[2] ==  expected_has_sse3);
+
+  }
+
 
   SECTION( "has_avx2_right" ){