diff --git a/Makefile.inc b/Makefile.inc
index 88a9a63..cdebd1b 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -113,19 +113,20 @@
 # macros work on all formats understood by printf(1)
 # values are space separated if using more than one value
 #
-# int-add:       adds an arbitrary length list of integers
-# int-subtract:  subtracts the the second of two integers from the first
-# int-multiply:  multiplies an arbitrary length list of integers
-# int-divide:    divides the first integer by the second
-# int-remainder: arithmetic remainder of the first number divided by the second
-# int-lt:        1 if the first value is less than the second.  0 otherwise
-# int-gt:        1 if the first values is greater than the second.  0 otherwise
-# int-eq:        1 if the two values are equal.  0 otherwise
-# int-align:     align $1 to $2 units
-# file-size:     returns the filesize of the given file
-# tolower:       returns the value in all lowercase
-# toupper:       returns the value in all uppercase
-# ws_to_under:   returns the value with any whitespace changed to underscores
+# int-add:        adds an arbitrary length list of integers
+# int-subtract:   subtracts the the second of two integers from the first
+# int-multiply:   multiplies an arbitrary length list of integers
+# int-divide:     divides the first integer by the second
+# int-remainder:  arithmetic remainder of the first number divided by the second
+# int-shift-left: Shift $1 left by $2 bits
+# int-lt:         1 if the first value is less than the second.  0 otherwise
+# int-gt:         1 if the first values is greater than the second.  0 otherwise
+# int-eq:         1 if the two values are equal.  0 otherwise
+# int-align:      align $1 to $2 units
+# file-size:      returns the filesize of the given file
+# tolower:        returns the value in all lowercase
+# toupper:        returns the value in all uppercase
+# ws_to_under:    returns the value with any whitespace changed to underscores
 _toint=$(shell printf "%d" $1)
 _int-add2=$(shell expr $(call _toint,$1) + $(call _toint,$2))
 int-add=$(if $(filter 1,$(words $1)),$(strip $1),$(call int-add,$(call _int-add2,$(word 1,$1),$(word 2,$1)) $(wordlist 3,$(words $1),$1)))
@@ -134,6 +135,7 @@
 int-multiply=$(if $(filter 1,$(words $1)),$(strip $1),$(call int-multiply,$(call _int-multiply2,$(word 1,$1),$(word 2,$1)) $(wordlist 3,$(words $1),$1)))
 int-divide=$(if $(filter 1,$(words $1)),$(strip $1),$(shell expr $(call _toint,$(word 1,$1)) / $(call _toint,$(word 2,$1))))
 int-remainder=$(if $(filter 1,$(words $1)),$(strip $1),$(shell expr $(call _toint,$(word 1,$1)) % $(call _toint,$(word 2,$1))))
+int-shift-left=$(shell echo "$(call _toint,$(word 1, $1)) * (2 ^ $(call _toint,$(word 2, $1)))" | bc)
 int-lt=$(if $(filter 1,$(words $1)),$(strip $1),$(shell expr $(call _toint,$(word 1,$1)) \< $(call _toint,$(word 2,$1))))
 int-gt=$(if $(filter 1,$(words $1)),$(strip $1),$(shell expr $(call _toint,$(word 1,$1)) \> $(call _toint,$(word 2,$1))))
 int-eq=$(if $(filter 1,$(words $1)),$(strip $1),$(shell expr $(call _toint,$(word 1,$1)) = $(call _toint,$(word 2,$1))))