x86: cpu: Detect Conroe CPUs and their slow shuffle unit

9 years ago · 8e9cd81d29
parent 7d7355aa92
commit 8e9cd81d29
1 changed files with 6 additions and 0 deletions
--- a/libavutil/x86/cpu.c
+++ b/libavutil/x86/cpu.c
@ -221,6 +221,12 @@ int ff_get_cpu_flags_x86(void)
         * functions on the Atom. */
        if (family == 6 && model == 28)
            rval |= AV_CPU_FLAG_ATOM;
+
+        /* Conroe has a slow shuffle unit. Check the model number to ensure not
+         * to include crippled low-end Penryns and Nehalems that lack SSE4. */
+        if ((rval & AV_CPU_FLAG_SSSE3) && !(rval & AV_CPU_FLAG_SSE4) &&
+            family == 6 && model < 23)
+            rval |= AV_CPU_FLAG_SSSE3SLOW;
    }

 #endif /* cpuid */