Add support for input image with int8_t format

Add support for input imsage with int8_t format (e.g., for HPS model)

Change-Id: I7084af19fcb15f9ca66fcb5f881a127dc349a953

build_tools/gen_mlmodel_input.py

diff --git a/build_tools/gen_mlmodel_input.py b/build_tools/gen_mlmodel_input.py
index fb87b3a..bbcd8d0 100755
--- a/build_tools/gen_mlmodel_input.py
+++ b/build_tools/gen_mlmodel_input.py
@@ -36,6 +36,8 @@
                     help='Indicate it is quant model (default: False)')
 parser.add_argument('--r', dest='float_input_range', default="-1.0, 1.0",
                     help='Float model input range (default: "-1.0, 1.0")')
+parser.add_argument('--sgn', dest='is_signed', action='store_true',
+                    help='Indicate the input is signed (default: False)')
 args = parser.parse_args()
 
 
@@ -50,7 +52,7 @@
                 file.write(struct.pack("<f", d))
 
 
-def gen_mlmodel_input(input_name, output_file, input_shape, is_quant):
+def gen_mlmodel_input(input_name, output_file, input_shape, is_quant, is_signed):
     if not os.path.exists(input_name):
         raise RuntimeError("Input file %s doesn't exist" % {input_name})
     if len(input_shape) < 3:
@@ -73,6 +75,8 @@
             low = np.min(float_input_range)
             high = np.max(float_input_range)
             input = (high - low) * input / 255.0 + low
+        elif is_signed:
+            input -= 128
     write_binary_file(output_file, input, is_quant, is_audio)
 
 
@@ -81,4 +85,4 @@
     input_shape = [int(x) for x in args.input_shape.split(',')]
     float_input_range = [float(x) for x in args.float_input_range.split(',')]
     gen_mlmodel_input(args.input_name, args.output_file,
-                      input_shape, args.is_quant)
+                      input_shape, args.is_quant, args.is_signed)

cmake/iree_model_input.cmake

diff --git a/cmake/iree_model_input.cmake b/cmake/iree_model_input.cmake
index 0871799..578e53a 100644
--- a/cmake/iree_model_input.cmake
+++ b/cmake/iree_model_input.cmake
@@ -26,7 +26,7 @@
 function(iree_model_input)
   cmake_parse_arguments(
     _RULE
-    "QUANT"
+    "QUANT;SIGNED"
     "NAME;SHAPE;SRC;RANGE"
     ""
     ${ARGN}
@@ -62,6 +62,9 @@
   if(_RULE_QUANT)
     list(APPEND _ARGS "--q")
   endif()
+  if(_RULE_SIGNED)
+    list(APPEND _ARGS "--sgn")
+  endif()
 
   # Replace dependencies passed by ::name with iree::package::name
   iree_package_ns(_PACKAGE_NS)