COMPMID-661: directconv-uint8 (#20)

Change-Id: I84f7a1ce3658be0d3c91e65096467258af48f0b6
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/94341
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/src/core/utils/quantization/AsymmHelpers.cpp b/src/core/utils/quantization/AsymmHelpers.cpp
new file mode 100644
index 0000000000..4ba5f44efa
--- /dev/null
+++ b/src/core/utils/quantization/AsymmHelpers.cpp
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2017 ARM Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include "arm_compute/core/utils/quantization/AsymmHelpers.h"
+
+#include <cmath>
+#include <limits>
+#include <numeric>
+
+using namespace arm_compute::quantization;
+
+arm_compute::Error arm_compute::quantization::calculate_quantized_multiplier_less_than_one(double multiplier,
+                                                                                           int   *quant_multiplier,
+                                                                                           int   *right_shift)
+{
+    ARM_COMPUTE_RETURN_ERROR_ON(quant_multiplier == nullptr);
+    ARM_COMPUTE_RETURN_ERROR_ON(right_shift == nullptr);
+    ARM_COMPUTE_RETURN_ERROR_ON(multiplier < 0);
+    ARM_COMPUTE_RETURN_ERROR_ON(multiplier >= 1);
+    if(multiplier == 0)
+    {
+        *quant_multiplier = 0;
+        *right_shift      = 0;
+        return arm_compute::Error{};
+    }
+    const double q = std::frexp(multiplier, right_shift);
+    *right_shift *= -1;
+    auto q_fixed = static_cast<int64_t>(round(q * (1ll << 31)));
+    ARM_COMPUTE_RETURN_ERROR_ON(q_fixed > (1ll << 31));
+    if(q_fixed == (1ll << 31))
+    {
+        q_fixed /= 2;
+        --*right_shift;
+    }
+    ARM_COMPUTE_RETURN_ERROR_ON(*right_shift < 0);
+    ARM_COMPUTE_RETURN_ERROR_ON(q_fixed > std::numeric_limits<int32_t>::max());
+    *quant_multiplier = static_cast<int>(q_fixed);
+
+    return arm_compute::Error{};
+}
\ No newline at end of file