diff --git a/AUTHORS b/AUTHORS
index f892145db..89b7e55ed 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -28,6 +28,7 @@ Authors, for copyright and licensing purposes.
  * Mans Rullgard
  * Matt Sarett
  * Mike Klein
+ * Mike Williams
  * Mohammad Seet
  * Pascal Massimino
  * Paul Schmidt
diff --git a/pngread.c b/pngread.c
index 0033089ad..b921c9b40 100644
--- a/pngread.c
+++ b/pngread.c
@@ -4113,7 +4113,7 @@ png_image_finish_read(png_imagep image, png_const_colorp background,
             row_stride = (png_int_32)/*SAFE*/png_row_stride;
 
          if (row_stride < 0)
-            check = -(png_uint_32)row_stride;
+            check = 0U - (png_uint_32)row_stride;
 
          else
             check = (png_uint_32)row_stride;
diff --git a/pngwrite.c b/pngwrite.c
index 2c95eb66c..42b29d559 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -2030,7 +2030,7 @@ png_image_write_main(png_voidp argument)
             display->row_stride = (png_int_32)/*SAFE*/png_row_stride;
 
          if (display->row_stride < 0)
-            check = -(png_uint_32)display->row_stride;
+            check = 0U - (png_uint_32)display->row_stride;
 
          else
             check = (png_uint_32)display->row_stride;