Replace TENSOR_QUANT16_ASYMM with TENSOR_QUANT16_SYMM

* Update doc string
* Update zero point mutation to check for symmetric quantization

Fix: 118671831
Test: VtsHalNeuralnetworksV1_2TargetTest
Change-Id: Id1999c793c839b892cfe45cbb245611b12db2a72
Merged-In: Id1999c793c839b892cfe45cbb245611b12db2a72
(cherry picked from commit 48c8820bac243e7eaff680056f2145f1b3b1ab2a)
diff --git a/neuralnetworks/1.2/types.hal b/neuralnetworks/1.2/types.hal
index 366e626..fe9b312 100644
--- a/neuralnetworks/1.2/types.hal
+++ b/neuralnetworks/1.2/types.hal
@@ -33,15 +33,13 @@
     /**
      * A tensor of 16 bit signed integers that represent real numbers.
      *
-     * Attached to this tensor are two numbers that are used to convert the 16
-     * bit integer to the real value and vice versa. These two numbers are:
-     * - scale: a 32 bit floating point value greater than zero.
-     * - zeroPoint: a 32 bit integer, in range [-32768, 32767].
+     * Attached to this tensor is a number representing real value scale that is
+     * used to convert the 16 bit number to a real value in the following way:
+     * realValue = integerValue * scale.
      *
-     * The formula is:
-     * realValue = (integerValue - zeroPoint) * scale.
+     * scale is a 32 bit floating point with value greater then zero.
      */
-    TENSOR_QUANT16_ASYMM = 7,
+    TENSOR_QUANT16_SYMM = 7,
     /** A tensor of 16 bit floating point values. */
     TENSOR_FLOAT16 = 8,
 };
diff --git a/neuralnetworks/1.2/vts/functional/ValidateModel.cpp b/neuralnetworks/1.2/vts/functional/ValidateModel.cpp
index e309642..c4f1b5e 100644
--- a/neuralnetworks/1.2/vts/functional/ValidateModel.cpp
+++ b/neuralnetworks/1.2/vts/functional/ValidateModel.cpp
@@ -161,7 +161,7 @@
         case OperandType::TENSOR_FLOAT32:
         case OperandType::TENSOR_INT32:
         case OperandType::TENSOR_QUANT8_ASYMM:
-        case OperandType::TENSOR_QUANT16_ASYMM:
+        case OperandType::TENSOR_QUANT16_SYMM:
             return 0;
         default:
             return 0;
@@ -193,7 +193,7 @@
         case OperandType::TENSOR_INT32:
             return -1.0f;
         case OperandType::TENSOR_QUANT8_ASYMM:
-        case OperandType::TENSOR_QUANT16_ASYMM:
+        case OperandType::TENSOR_QUANT16_SYMM:
             return 0.0f;
         default:
             return 0.0f;
@@ -225,8 +225,8 @@
             return {1};
         case OperandType::TENSOR_QUANT8_ASYMM:
             return {-1, 256};
-        case OperandType::TENSOR_QUANT16_ASYMM:
-            return {-32769, 32768};
+        case OperandType::TENSOR_QUANT16_SYMM:
+            return {-32769, -1, 1, 32768};
         default:
             return {};
     }
@@ -279,7 +279,7 @@
             newOperand.zeroPoint = 0;
             break;
         case OperandType::TENSOR_QUANT8_ASYMM:
-        case OperandType::TENSOR_QUANT16_ASYMM:
+        case OperandType::TENSOR_QUANT16_SYMM:
             newOperand.dimensions =
                 operand->dimensions.size() > 0 ? operand->dimensions : hidl_vec<uint32_t>({1});
             newOperand.scale = operand->scale != 0.0f ? operand->scale : 1.0f;