Merge pull request #49 from definelicht/fix-const-log

Fix ConstLog2
definelicht · Sep 21, 2021 · 988dc99 · 988dc99
2 parents f9d3555 + ee58342
commit 988dc99
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Showing 3 changed files with 6 additions and 5 deletions.
diff --git a/include/hlslib/xilinx/Flatten.h b/include/hlslib/xilinx/Flatten.h
@@ -117,9 +117,10 @@ namespace {
 template <signed long begin, signed long end>
 struct BitsToRepresent {
   static constexpr unsigned kBits =
-      (begin < 0 || end < 0)
-          ? (ConstLog2(hlslib::max(hlslib::abs(begin), hlslib::abs(end))) + 1)
-          : ConstLog2(hlslib::max(begin, end));
+      1 +
+      ((begin < 0 || end < 0)
+           ? (ConstLog2(hlslib::max(hlslib::abs(begin), hlslib::abs(end))) + 1)
+           : ConstLog2(hlslib::max(begin, end)));
   using type = typename std::conditional<(begin < 0 || end < 0), ap_int<kBits>,
                                          ap_uint<kBits>>::type;
 };

diff --git a/include/hlslib/xilinx/ShiftRegister.h b/include/hlslib/xilinx/ShiftRegister.h
@@ -48,7 +48,7 @@ struct _MaxImpl<I, Is...> {
 
 template <typename T, size_t Size>
 class _ShiftRegisterStageImpl {
-  using Index_t = ap_uint<hlslib::ConstLog2(Size)>;
+  using Index_t = ap_uint<hlslib::ConstLog2(Size) + 1>;
 
  public:
   T Shift(T const &next) {

diff --git a/include/hlslib/xilinx/Utility.h b/include/hlslib/xilinx/Utility.h
@@ -12,7 +12,7 @@ namespace hlslib {
 // Constexpr methods for compile-time computations
 
 constexpr unsigned char ConstLog2(unsigned long val) {
-  return val == 0 ? 0 : 1 + ConstLog2(val >> 1);
+  return val <= 1 ? 0 : 1 + ConstLog2(val >> 1);
 }
 
 // Integer division with ceil instead of floor