base/dispatch.c, base/dispatch-x86ish.S: Add opcode to `rdrand_works_p'.

[catacomb] / base / dispatch.c

diff --git a/base/dispatch.c b/base/dispatch.c
index 7652f32..bda7f88 100644 (file)
--- a/base/dispatch.c
+++ b/base/dispatch.c
@@ -61,7 +61,7 @@ enum {
 struct cpuid { unsigned a, b, c, d; };
 extern int dispatch_x86ish_cpuid(struct cpuid *, unsigned a, unsigned c);
 extern int dispatch_x86ish_xmmregisters_p(void);
-extern int dispatch_x86ish_rdrand(unsigned *);
+extern int dispatch_x86ish_rdrand(unsigned op, unsigned *);
 
 static void cpuid(struct cpuid *cc, unsigned a, unsigned c)
 {
@@ -130,28 +130,36 @@ static int xmm_registers_available_p(void)
  *             that it's already been verified to be safe to issue.
  */
 
-static int rdrand_works_p(void)
+enum { OP_RDRAND, OP_RDSEED };
+
+static int rdrand_works_p(unsigned op)
 {
   unsigned ref, x, i;
+  const char *what;
+
+  switch (op) {
+    case OP_RDRAND: what = "RDRAND"; break;
+    default: assert(!"unexpected op");
+  }
 
   /* Check that it doesn't always give the same answer.  Try four times: this
    * will fail with probability %$2^{-128}$% with a truly random generator,
    * which seems fair enough.
    */
-  if (dispatch_x86ish_rdrand(&ref)) goto fail;
+  if (dispatch_x86ish_rdrand(op, &ref)) goto fail;
   for (i = 0; i < 4; i++) {
-    if (dispatch_x86ish_rdrand(&x)) goto fail;
+    if (dispatch_x86ish_rdrand(op, &x)) goto fail;
     if (x != ref) goto not_stuck;
   }
-  dispatch_debug("RDRAND always returns 0x%08x!", ref);
+  dispatch_debug("%s always returns 0x%08x!", what, ref);
   return (0);
 
 not_stuck:
-  dispatch_debug("RDRAND instruction looks plausible");
+  dispatch_debug("%s instruction looks plausible", what);
   return (1);
 
 fail:
-  dispatch_debug("RDRAND instruction fails too often");
+  dispatch_debug("%s instruction fails too often", what);
   return (0);
 }
 
@@ -509,7 +517,7 @@ int cpu_feature_p(int feat)
                 xmm_registers_available_p());
     CASE_CPUFEAT(X86_RDRAND, "x86:rdrand",
                 cpuid_feature_p(CPUID_1_C, CPUID1C_RDRAND) &&
-                rdrand_works_p());
+                rdrand_works_p(OP_RDRAND));
     CASE_CPUFEAT(X86_AVX, "x86:avx",
                 cpuid_feature_p(CPUID_1_C, CPUID1C_AVX) &&
                 xmm_registers_available_p());