Add rng to Context, start using ctx->verbose

Signed-off-by: Clifford Wolf <clifford@clifford.at>

1 files changed, 52 insertions, 0 deletions

diff --git a/common/nextpnr.h b/common/nextpnr.h
index 08c941a5..6d0dab86 100644
--- a/common/nextpnr.h
+++ b/common/nextpnr.h
@@ -275,6 +275,58 @@ struct Context : Arch
     bool verbose = false;
 
     Context(ArchArgs args) : Arch(args) {}
+
+    // --------------------------------------------------------------
+
+    uint64_t rngstate = 0x3141592653589793;
+
+    uint64_t rng64()
+    {
+        // xorshift64star
+        // https://arxiv.org/abs/1402.6246
+        rngstate ^= rngstate >> 12;
+        rngstate ^= rngstate << 25;
+        rngstate ^= rngstate >> 27;
+        return rngstate * 0x2545F4914F6CDD1D;
+    }
+
+    int rng()
+    {
+        return rng64() & 0x3fffffff;
+    }
+
+    int rng(int n)
+    {
+        assert(n > 0);
+
+        // round up to power of 2
+        int m = n - 1;
+        m |= (m >> 1);
+        m |= (m >> 2);
+        m |= (m >> 4);
+        m |= (m >> 8);
+        m |= (m >> 16);
+        m += 1;
+
+        while (1) {
+            int x = rng64() & (m-1);
+            if (x < n) return x;
+        }
+    }
+
+    void rngseed(uint64_t seed)
+    {
+        rngstate = seed ? seed : 0x3141592653589793;
+        for (int i = 0; i < 5; i++) rng64();
+    }
+
+    template<typename T>
+    void shuffle(std::vector<T> &a) {
+        for (size_t i = 0; i != a.size(); i++) {
+            size_t j = i + rng(a.size() - i);
+            if (j > i) std::swap(a[i], a[j]);
+        }
+    }
 };
 
 NEXTPNR_NAMESPACE_END