Remove unused Simics code in crypto/bn/asm/x86_64-gcc.c.

Change-Id: If9c5031855c0acfafb73caba169e146f0e16f706
Reviewed-on: https://boringssl-review.googlesource.com/7093
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/crypto/bn/asm/x86_64-gcc.c b/crypto/bn/asm/x86_64-gcc.c
index 0496b95..30275d3 100644
--- a/crypto/bn/asm/x86_64-gcc.c
+++ b/crypto/bn/asm/x86_64-gcc.c
@@ -220,7 +220,6 @@
   return ret & 1;
 }
 
-#ifndef SIMICS
 BN_ULONG bn_sub_words(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
                       int n) {
   BN_ULONG ret;
@@ -246,65 +245,6 @@
 
   return ret & 1;
 }
-#else
-/* Simics 1.4<7 has buggy sbbq:-( */
-#define BN_MASK2 0xffffffffffffffffL
-BN_ULONG bn_sub_words(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n) {
-  BN_ULONG t1, t2;
-  int c = 0;
-
-  if (n <= 0) {
-    return (BN_ULONG)0;
-  }
-
-  for (;;) {
-    t1 = a[0];
-    t2 = b[0];
-    r[0] = (t1 - t2 - c) & BN_MASK2;
-    if (t1 != t2) {
-      c = (t1 < t2);
-    }
-    if (--n <= 0) {
-      break;
-    }
-
-    t1 = a[1];
-    t2 = b[1];
-    r[1] = (t1 - t2 - c) & BN_MASK2;
-    if (t1 != t2) {
-      c = (t1 < t2);
-    }
-    if (--n <= 0) {
-      break;
-    }
-
-    t1 = a[2];
-    t2 = b[2];
-    r[2] = (t1 - t2 - c) & BN_MASK2;
-    if (t1 != t2) {
-      c = (t1 < t2);
-    }
-    if (--n <= 0) {
-      break;
-    }
-
-    t1 = a[3];
-    t2 = b[3];
-    r[3] = (t1 - t2 - c) & BN_MASK2;
-    if (t1 != t2) {
-      c = (t1 < t2);
-    }
-    if (--n <= 0) {
-      break;
-    }
-
-    a += 4;
-    b += 4;
-    r += 4;
-  }
-  return c;
-}
-#endif
 
 /* mul_add_c(a,b,c0,c1,c2)  -- c+=a*b for three word number c=(c2,c1,c0) */
 /* mul_add_c2(a,b,c0,c1,c2) -- c+=2*a*b for three word number c=(c2,c1,c0) */