Style, comments.

src/chain/chain_state.cpp

@@ -428,7 +428,7 @@ size_t chain_state::bip9_bit0_height(size_t height,
     const auto activation_height = bip9_bit0_active_checkpoint.height();
 
     // Require bip9_bit0 hash at heights at/above bip9_bit0 activation.
-    return height >= activation_height ? activation_height : map::unrequested;
+    return height < activation_height ? map::unrequested : activation_height;
 }
 
 size_t chain_state::bip9_bit1_height(size_t height,
@@ -437,7 +437,7 @@ size_t chain_state::bip9_bit1_height(size_t height,
     const auto activation_height = bip9_bit1_active_checkpoint.height();
 
     // Require bip9_bit1 hash at heights at/above bip9_bit1 activation.
-    return height >= activation_height ? activation_height : map::unrequested;
+    return height < activation_height ? map::unrequested : activation_height;
 }
 
 // Public static
@@ -472,11 +472,11 @@ chain_state::map chain_state::get_map(size_t height,
     // The most recent past retarget height.
     map.timestamp_retarget = retarget_height(height, forks, interval);
 
-    // The checkpoint above which bip9_bit0 rules are enforced.
+    // The checkpoint at/above which bip9_bit0 rules are enforced.
     map.bip9_bit0_height = bip9_bit0_height(height,
         settings.bip9_bit0_active_checkpoint);
 
-    // The checkpoint above which bip9_bit1 rules are enforced.
+    // The checkpoint at/above which bip9_bit1 rules are enforced.
     map.bip9_bit1_height = bip9_bit1_height(height,
         settings.bip9_bit1_active_checkpoint);