From 390ac799e791127e9d12fe266860e315129998bb Mon Sep 17 00:00:00 2001
From: Daniel <daniel@poradnik-webmastera.com>
Date: Sat, 25 Nov 2017 17:25:19 +0100
Subject: [PATCH] Added CPUID check

---
 RakeDiagSearch/RakeDiagSearch/Generator.cpp |   2 -
 RakeDiagSearch/RakeDiagSearch/main.cpp      | 102 ++++++++++++++++++--
 2 files changed, 95 insertions(+), 9 deletions(-)

diff --git a/RakeDiagSearch/RakeDiagSearch/Generator.cpp b/RakeDiagSearch/RakeDiagSearch/Generator.cpp
index 07c572a..38dec5e 100644
--- a/RakeDiagSearch/RakeDiagSearch/Generator.cpp
+++ b/RakeDiagSearch/RakeDiagSearch/Generator.cpp
@@ -460,8 +460,6 @@ inline void Generator::StartImpl()
   int cellValue;    // New value for the cell
   int oldCellValue; // Old value from the cell
 
-  int stop = 0;     // Flag of finishing the computing
-
   // Create constant copies of used fields to speedup calculations
   const int cellsInPath = this->cellsInPath;
   const int keyValue = this->keyValue;
diff --git a/RakeDiagSearch/RakeDiagSearch/main.cpp b/RakeDiagSearch/RakeDiagSearch/main.cpp
index 9d8338e..a06f48d 100644
--- a/RakeDiagSearch/RakeDiagSearch/main.cpp
+++ b/RakeDiagSearch/RakeDiagSearch/main.cpp
@@ -1,10 +1,13 @@
-# include <iostream>
-# include <fstream>
-# include <string>
-# include <sys/stat.h>
-# include "boinc_api.h"
-
-# include "MovePairSearch.h"
+#include <iostream>
+#include <fstream>
+#include <string>
+#include <sys/stat.h>
+#include "boinc_api.h"
+#include "MovePairSearch.h"
+#if defined(__i386__) || defined (__x86_64__)
+#include <cpuid.h>
+#include <stdio.h>
+#endif
 
 using namespace std;
 
@@ -126,3 +129,88 @@ int main(int argumentsCount, char* argumentsValues[])
                    // will be shown). 
   return 0;
 }
+
+// Do not check x86 CPU features if SSE2 is not required. Very old CPUs may not support CPUID.
+// Code below uses C stdio because C++ iostreams are not initialized yet and app would crash.
+// This function is called before main() starts.
+#if (defined(__i386__) || defined (__x86_64__)) && defined(__SSE2__)
+__attribute__((constructor(101), target("no-sse")))
+void CheckCpuid()
+{
+  unsigned int a, b, c, d;
+
+  if (!__get_cpuid(1, &a, &b, &c, &d))
+  {
+    fprintf(stderr, "CPUID instruction is not supported by your CPU!\n");
+    exit(1);
+  }
+
+  if (0 == (d & bit_SSE2))
+  {
+    fprintf(stderr, "SSE2 instructions are not supported by your CPU!\n");
+    exit(1);
+  }
+
+#ifdef __AVX__
+  if (0 == (c & bit_AVX))
+  {
+    fprintf(stderr, "AVX instructions are not supported by your CPU!\n");
+    exit(1);
+  }
+
+  // AVX also needs OS support, check for it
+  if (0 == (c & bit_OSXSAVE))
+  {
+    fprintf(stderr, "OSXSAVE instructions are not supported by your CPU!\n");
+    exit(1);
+  }
+
+  unsigned int eax, edx;
+  unsigned int ecx = 0; // _XCR_XFEATURE_ENABLED_MASK
+  __asm__ ("xgetbv" : "=a" (eax), "=d" (edx) : "c" (ecx));
+  if (0x6 != (eax & 0x6)) // XSTATE_SSE | XSTATE_YMM
+  {
+    fprintf(stderr, "AVX instructions are not supported by your OS!\n");
+    exit(1);
+  }
+#endif
+
+#ifdef __AVX2__
+  if (!__get_cpuid(7, &a, &b, &c, &d)) {
+    fprintf(stderr, "Extended CPUID 0x7 instruction is not supported by your CPU!\n");
+    exit(1);
+  }
+
+  if (0 == (b & bit_AVX2))
+  {
+    fprintf(stderr, "AVX2 instructions are not supported by your CPU!\n");
+    exit(1);
+  }
+#endif
+
+#ifdef __AVX512F__
+  // During comppilation following AVX512 instruction sets are enabled: F, CD, VL, BW, DQ
+  // Code directly uses F and VL. Compiler may emit instruction from other ones, so check them all
+
+  // We need data loaded during AVX and AVX2 checks, make sure we have it
+#if !defined(__AVX__) || !defined(__AVX2__)
+#error AVX or AVX2 is not enabled!
+#endif
+
+  const unsigned int avx512bits = bit_AVX512F | bit_AVX512DQ | bit_AVX512CD | bit_AVX512BW | bit_AVX512VL;
+
+  if (avx512bits != (b & avx512bits))
+  {
+    fprintf(stderr, "AVX512 instructions are not supported by your CPU!\n");
+    exit(1);
+  }
+
+  // AVX512 also needs OS support, check for it
+  if (0xe6 != (eax & 0xe6)) // XSTATE_SSE | XSTATE_YMM | XSTATE_OPMASK | XSTATE_ZMM | XSTATE_HI_ZMM
+  {
+    fprintf(stderr, "AVX512 instructions are not supported by your OS!\n");
+    exit(1);
+  }
+#endif
+}
+#endif