Add support for MMX checking.

5 files changed, 70 insertions, 11 deletions

diff --git a/test cases/common/139 simd/fallback.c b/test cases/common/139 simd/fallback.c
index 2b98304..ab435f4 100644
--- a/test cases/common/139 simd/fallback.c
+++ b/test cases/common/139 simd/fallback.c
@@ -1,7 +1,8 @@
 #include<simdfuncs.h>
 
 void increment_fallback(float arr[4]) {
-    for(int i=0; i<4; i++) {
+    int i;
+    for(i=0; i<4; i++) {
         arr[i]++;
     }
 }
diff --git a/test cases/common/139 simd/meson.build b/test cases/common/139 simd/meson.build
index b26d007..153b458 100644
--- a/test cases/common/139 simd/meson.build
+++ b/test cases/common/139 simd/meson.build
@@ -1,13 +1,33 @@
 project('simd', 'c')
 
+cc = meson.get_compiler('c')
+
 cdata = configuration_data()
 
-#cdata.set('HAVE_MMX', 1)
+# The idea is to have a simd module and then do something like:
+#
+# static_libs = simd.check('mysimdstuff',
+#   mmx : 'mmx_funcs.c',
+#   sse : 'sse_funcs.c',
+#   sse2 : 'sse2_funcs.c',
+#   <etc>
+#   configuration : cdata, # adds HAVE_XXX
+#   compiler : cc)
+#
+# and then have a target that uses the result in links_with.
+
+simdlibs = []
+
+if cc.has_argument('-mmmx')
+  cdata.set('HAVE_MMX', 1)
+  simdlibs += static_library('simd_mmx', 'simd_mmx.c', c_args : '-mmmx')
+endif
 
 configure_file(output : 'simdconfig.h',
   configuration : cdata)
 
-p = executable('simdtest', 'simdchecker.c', 'fallback.c')
+p = executable('simdtest', 'simdchecker.c', 'fallback.c',
+  link_with : simdlibs)
 
 test('simdtest', p)
 
diff --git a/test cases/common/139 simd/simd_mmx.c b/test cases/common/139 simd/simd_mmx.c
new file mode 100644
index 0000000..dc1d51c
--- /dev/null
+++ b/test cases/common/139 simd/simd_mmx.c
@@ -0,0 +1,22 @@
+#include<mmintrin.h>
+#include<cpuid.h>
+#include<stdint.h>
+
+int mmx_available() {
+    return __builtin_cpu_supports("mmx");
+}
+
+void increment_mmx(float arr[4]) {
+    /* Super ugly but we know that values in arr are always small
+     * enough to fit in int16;
+     */
+    __m64 packed = _mm_set_pi16(arr[3], arr[2], arr[1], arr[0]);
+    __m64 incr = _mm_set1_pi16(1);
+    __m64 result = _mm_add_pi16(packed, incr);
+    int64_t unpacker = _m_to_int64(result);
+    _mm_empty();
+    for(int i=0; i<4; i++) {
+        arr[i] = unpacker & ((1<<16)-1);
+        unpacker >>= 16;
+    }
+}
diff --git a/test cases/common/139 simd/simdchecker.c b/test cases/common/139 simd/simdchecker.c
index bcc6cef..d75af25 100644
--- a/test cases/common/139 simd/simdchecker.c
+++ b/test cases/common/139 simd/simdchecker.c
@@ -2,28 +2,36 @@
 #include<stdio.h>
 
 /*
- * A function that checks at runtime if simd acceleration is
- * available and calls the respective function if it is. Falls
- * back to plain C implementation if not.
+ * A function that checks at runtime which simd accelerations are
+ * available and calls the best one. Falls
+ * back to plain C implementation if SIMD is not available.
  */
 
 int main(int argc, char **argv) {
     float four[4] = {2.0, 3.0, 4.0, 5.0};
     const float expected[4] = {3.0, 4.0, 5.0, 6.0};
     void (*fptr)(float[4]) = NULL;
+    const char *type;
 
-#if HAVE_MMX
-    if(mmx_available()) {
+#if HAVE_SSE
+    /* Add here. The first matched one is used so put "better" instruction
+     * sets at the top.
+     */
+#elif HAVE_MMX
+    if(fptr == NULL && mmx_available()) {
         fptr = increment_mmx;
+        type = "MMX";
     }
 #endif
     if(fptr == NULL) {
         fptr = increment_fallback;
+        type = "fallback";
     }
+    printf("Using %s.\n", type);
     fptr(four);
     for(int i=0; i<4; i++) {
         if(four[i] != expected[i]) {
-            printf("Increment function failed.\n");
+            printf("Increment function failed, got %f expected %f.\n", four[i], expected[i]);
             return 1;
         }
     }
diff --git a/test cases/common/139 simd/simdfuncs.h b/test cases/common/139 simd/simdfuncs.h
index 17c627e..4b452fc 100644
--- a/test cases/common/139 simd/simdfuncs.h
+++ b/test cases/common/139 simd/simdfuncs.h
@@ -3,13 +3,21 @@
 #include<simdconfig.h>
 
 /* Yes, I do know that arr[4] decays into a pointer
- * here. Don't do this in real code but for test code
- * it is ok.
+ * as a function argument. Don't do this in real code
+ * but for this test it is ok.
  */
 
 void increment_fallback(float arr[4]);
 
 #if HAVE_MMX
+int mmx_available();
 void increment_mmx(float arr[4]);
 #endif
 
+#if HAVE_SSE
+#endif
+
+#if HAVE_SSE2
+#endif
+
+/* And so on. */