diff --git a/ANNOUNCE b/ANNOUNCE
index b08f0f6c4..b4bfe67ff 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -97,6 +97,7 @@ Version 1.5.6rc02 [October 27, 2011]
     code branches and complain about out-of-range shifts. 
 
 Version 1.5.6rc03 [October 27, 2011]
+  Renamed the LSR() macro to PNG_LSR() and added PNG_LSL() macro.
 
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diff --git a/CHANGES b/CHANGES
index ff7f7ef32..4b448f635 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3658,6 +3658,7 @@ Version 1.5.6rc02 [October 27, 2011]
     code branches and complain about out-of-range shifts. 
 
 Version 1.5.6rc03 [October 27, 2011]
+  Renamed the LSR() macro to PNG_LSR() and added PNG_LSL() macro.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/pngrutil.c b/pngrutil.c
index 374dfeb69..a7b584d67 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -2880,16 +2880,20 @@ png_combine_row(png_structp png_ptr, png_bytep dp, int display)
           * below to extract the relevant fields from a 64 bit value are faulted
           * if evaluated at compile time because the non-taken branch has an
           * invalid shift (negative or more than 31), hence the following.
-         */
+          *
+          * TO DO: Also identify the Intel C compiler here.
+          */
 #        if defined PNG_USE_COMPILE_TIME_MASKS && defined _MSC_VER
-#           define LSR(x,s) ((x)>>((s) & 0x1f))
+#           define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
+#           define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
 #        else
-#           define LSR(x,s) ((x)>>(s))
+#           define PNG_LSR(x,s) ((x)>>(s))
+#           define PNG_LSL(x,s) ((x)<<(s))
 #        endif
-#        define S_COPY(p,x) (((p)<4 ? LSR(0x80088822,(3-(p))*8+(7-(x))) :\
-           LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
-#        define B_COPY(p,x) (((p)<4 ? LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
-           LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
+#        define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
+           PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
+#        define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
+           PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
 
          /* Return a mask for pass 'p' pixel 'x' at depth 'd'.  The mask is
           * little endian - the first pixel is at bit 0 - however the extra
@@ -2897,7 +2901,8 @@ png_combine_row(png_structp png_ptr, png_bytep dp, int display)
           * within each byte, to match the PNG format.  This is done by XOR of
           * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
           */
-#        define PIXEL_MASK(p,x,d,s) (((1U<<(d))-1)<<(((x)*(d))^((s)?8-(d):0)))
+#        define PIXEL_MASK(p,x,d,s) \
+            (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
 
          /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
           */