diff --git a/backend/composite.c b/backend/composite.c
index 09b52e62..93dd9e63 100644
--- a/backend/composite.c
+++ b/backend/composite.c
@@ -58,7 +58,6 @@
 #include <malloc.h>
 #endif
 #include "common.h"
-#include "large.h"
 #include "composite.h"
 #include "pdf417.h"
 #include "gs1.h"
diff --git a/backend/imail.c b/backend/imail.c
index c3bd90c1..fe60215a 100644
--- a/backend/imail.c
+++ b/backend/imail.c
@@ -316,17 +316,8 @@ int imail(struct zint_symbol *symbol, unsigned char source[], int length) {
 
     for (read = 0; read < strlen(zip); read++) {
 
-        for (i = 0; i < 112; i++) {
-            x_reg[i] = accum[i];
-        }
-
-        for (i = 0; i < 9; i++) {
-            binary_add(accum, x_reg);
-        }
-
-        for (i = 0; i < 112; i++) {
-            x_reg[i] = 0;
-        }
+        binary_multiply(accum, "10");
+        binary_load(x_reg, "0", 1);
 
         for (i = 0; i < 4; i++) {
             if (ctoi(zip[read]) & (0x01 << i)) x_reg[i] = 1;
@@ -361,17 +352,8 @@ int imail(struct zint_symbol *symbol, unsigned char source[], int length) {
 
     for (read = 0; read < strlen(zip_adder); read++) {
 
-        for (i = 0; i < 112; i++) {
-            y_reg[i] = accum[i];
-        }
-
-        for (i = 0; i < 9; i++) {
-            binary_add(accum, y_reg);
-        }
-
-        for (i = 0; i < 112; i++) {
-            y_reg[i] = 0;
-        }
+        binary_multiply(accum, "10");
+        binary_load(y_reg, "0", 1);
 
         for (i = 0; i < 4; i++) {
             if (ctoi(zip_adder[read]) & (0x01 << i)) y_reg[i] = 1;
@@ -385,17 +367,8 @@ int imail(struct zint_symbol *symbol, unsigned char source[], int length) {
     /* tracking code */
 
     /* multiply by 10 */
-    for (i = 0; i < 112; i++) {
-        y_reg[i] = accum[i];
-    }
-
-    for (i = 0; i < 9; i++) {
-        binary_add(accum, y_reg);
-    }
-
-    for (i = 0; i < 112; i++) {
-        y_reg[i] = 0;
-    }
+    binary_multiply(accum, "10");
+    binary_load(y_reg, "0", 1);
 
     /* add first digit of tracker */
     for (i = 0; i < 4; i++) {
@@ -405,17 +378,8 @@ int imail(struct zint_symbol *symbol, unsigned char source[], int length) {
     binary_add(accum, y_reg);
 
     /* multiply by 5 */
-    for (i = 0; i < 112; i++) {
-        y_reg[i] = accum[i];
-    }
-
-    for (i = 0; i < 4; i++) {
-        binary_add(accum, y_reg);
-    }
-
-    for (i = 0; i < 112; i++) {
-        y_reg[i] = 0;
-    }
+    binary_multiply(accum, "5");
+    binary_load(y_reg, "0", 1);
 
     /* add second digit */
     for (i = 0; i < 4; i++) {
@@ -428,17 +392,8 @@ int imail(struct zint_symbol *symbol, unsigned char source[], int length) {
 
     for (read = 2; read < strlen(tracker); read++) {
 
-        for (i = 0; i < 112; i++) {
-            y_reg[i] = accum[i];
-        }
-
-        for (i = 0; i < 9; i++) {
-            binary_add(accum, y_reg);
-        }
-
-        for (i = 0; i < 112; i++) {
-            y_reg[i] = 0;
-        }
+        binary_multiply(accum, "10");
+        binary_load(y_reg, "0", 1);
 
         for (i = 0; i < 4; i++) {
             if (ctoi(tracker[read]) & (0x01 << i)) y_reg[i] = 1;
diff --git a/backend/large.c b/backend/large.c
index b7211a40..0f574e34 100644
--- a/backend/large.c
+++ b/backend/large.c
@@ -115,6 +115,26 @@ void binary_subtract(short int accumulator[], short int input_buffer[]) {
     binary_add(accumulator, sub_buffer);
 }
 
+void binary_multiply(short int reg[], char data[]) {
+    /* Multiply the contents of reg[] by a number */
+    short int temp[112] = {0};
+    short int accum[112] = {0};
+    int i;
+    
+    binary_load(temp, data, strlen(data));
+    
+    for (i = 0; i < 102; i++) {
+        if (temp[i] == 1) {
+            binary_add(accum, reg);
+        }
+        shiftup(reg);
+    }
+    
+    for (i = 0; i < 112; i++) {
+        reg[i] = accum[i];
+    }
+}
+
 void shiftdown(short int buffer[]) {
     int i;
 
diff --git a/backend/large.h b/backend/large.h
index 4a8e69be..01f89aa3 100644
--- a/backend/large.h
+++ b/backend/large.h
@@ -42,6 +42,7 @@ extern void binary_subtract(short int accumulator[], short int input_buffer[]);
 extern void shiftdown(short int buffer[]);
 extern void shiftup(short int buffer[]);
 extern short int islarger(short int accum[], short int reg[]);
+extern void binary_multiply(short int reg[], char data[]);
 
 #ifdef __cplusplus
 }
diff --git a/backend/mailmark.c b/backend/mailmark.c
index e15414fc..269240a9 100644
--- a/backend/mailmark.c
+++ b/backend/mailmark.c
@@ -293,14 +293,7 @@ int mailmark(struct zint_symbol *symbol, unsigned char source[], int length) {
         for (i = 0; i < 9; i++) {
             switch (pattern[i]) {
                 case 'F':
-                    for (j = 0; j < 112; j++) {
-                        temp[j] = b[j];
-                    }
-                    
-                    // b *= 26
-                    for (j = 1; j < 26; j++) {
-                        binary_add(b, temp);
-                    }
+                    binary_multiply(b, "26");
                     
                     binary_load(temp, "0", 1);
                     for (j = 0; j < 5; j++) {
@@ -310,14 +303,7 @@ int mailmark(struct zint_symbol *symbol, unsigned char source[], int length) {
                     binary_add(b, temp);
                     break;
                 case 'L':
-                    for (j = 0; j < 112; j++) {
-                        temp[j] = b[j];
-                    }
-                    
-                    // b *= 20
-                    for (j = 1; j < 20; j++) {
-                        binary_add(b, temp);
-                    }
+                    binary_multiply(b, "20");
                     
                     binary_load(temp, "0", 1);
                     for (j = 0; j < 5; j++) {
@@ -327,14 +313,7 @@ int mailmark(struct zint_symbol *symbol, unsigned char source[], int length) {
                     binary_add(b, temp);
                     break;
                 case 'N':
-                    for (j = 0; j < 112; j++) {
-                        temp[j] = b[j];
-                    }
-                    
-                    for (j = 1; j < 10; j++) {
-                        // b *= 10
-                        binary_add(b, temp);
-                    }
+                    binary_multiply(b, "10");
                     
                     binary_load(temp, "0", 1);
                     for (j = 0; j < 4; j++) {
@@ -390,14 +369,7 @@ int mailmark(struct zint_symbol *symbol, unsigned char source[], int length) {
     binary_add(cdv, destination_postcode);
     
     // Multiply by 100,000,000
-    for (i = 0; i < 8; i++) {
-        binary_load(temp, "0", 1);
-        binary_add(temp, cdv);
-        
-        for (j = 1; j < 10; j++) {
-            binary_add(cdv, temp);
-        }
-    }
+    binary_multiply(cdv, "100000000");
     
     // Add Item ID
     binary_load(temp, "0", 1);
@@ -406,26 +378,12 @@ int mailmark(struct zint_symbol *symbol, unsigned char source[], int length) {
     }
     binary_add(cdv, temp);
     
-    if (length == 22) {
+    if (length == 22) {  
         // Barcode C - Multiply by 100
-        for (i = 0; i < 2; i++) {
-            binary_load(temp, "0", 1);
-            binary_add(temp, cdv);
-
-            for (j = 1; j < 10; j++) {
-                binary_add(cdv, temp);
-            }
-        }
+        binary_multiply(cdv, "100");
     } else {
         // Barcode L - Multiply by 1,000,000
-        for (i = 0; i < 6; i++) {
-            binary_load(temp, "0", 1);
-            binary_add(temp, cdv);
-
-            for (j = 1; j < 10; j++) {
-                binary_add(cdv, temp);
-            }
-        }
+        binary_multiply(cdv, "1000000");
     }
     
     // Add Supply Chain ID
@@ -436,12 +394,7 @@ int mailmark(struct zint_symbol *symbol, unsigned char source[], int length) {
     binary_add(cdv, temp);
     
     // Multiply by 15
-    binary_load(temp, "0", 1);
-    binary_add(temp, cdv);
-
-    for (j = 1; j < 15; j++) {
-        binary_add(cdv, temp);
-    }
+    binary_multiply(cdv, "15");
     
     // Add Class
     binary_load(temp, "0", 1);
@@ -451,12 +404,7 @@ int mailmark(struct zint_symbol *symbol, unsigned char source[], int length) {
     binary_add(cdv, temp);
     
     // Multiply by 5
-    binary_load(temp, "0", 1);
-    binary_add(temp, cdv);
-
-    for (j = 1; j < 5; j++) {
-        binary_add(cdv, temp);
-    }
+    binary_multiply(cdv, "5");
     
     // Add Format
     binary_load(temp, "0", 1);
@@ -466,12 +414,7 @@ int mailmark(struct zint_symbol *symbol, unsigned char source[], int length) {
     binary_add(cdv, temp);
     
     // Multiply by 4
-    binary_load(temp, "0", 1);
-    binary_add(temp, cdv);
-
-    for (j = 1; j < 4; j++) {
-        binary_add(cdv, temp);
-    }
+    binary_multiply(cdv, "4");
     
     // Add Version ID
     binary_load(temp, "0", 1);
diff --git a/backend/pdf417.c b/backend/pdf417.c
index 62eb4cd6..7170503d 100644
--- a/backend/pdf417.c
+++ b/backend/pdf417.c
@@ -53,8 +53,6 @@
 #endif
 #include "pdf417.h"
 #include "common.h"
-#include "large.h"
-
 /*
    Three figure numbers in comments give the location of command equivalents in the
    original Visual Basic source code file pdf417.frm