Added functions to stddef module

include/stddef.a02

@@ -28,7 +28,7 @@ RESRXY: LDX TEMP1   ;Load X Index
         LDY TEMP2   ;Load Y Index
         RTS
 
-;Set Destinatioon Pointer to Source Pointer
+;Set Destination Pointer to Source Pointer
 SETDSS: JSR GETSRC  ;Get Destination Pointer
         JMP SETDST  ;Store in Source Pointer
 
@@ -62,3 +62,18 @@ GETDST: LDX DSTLO
 GETSRC: LDX SRCLO
         LDY SRCHI
         RTS
+
+;Add to Destination Address
+ADDDST: LDX #DSTLO       ;Set Index
+        BNE ADDZPW      ;and Execute ADDZPW
+
+;Add to Source Address
+ADDSRC: LDX #SRCLO       ;Set Index and Drop into ADDZPW
+        
+;Add to Zero Page Word
+ADDZPW: CLC             ;Clear Carry
+        ADC 0,X         ;Add Argument to LSB
+        STA 0,X         ;and Save Result
+        BCC ADDZPX      ;If Carry
+        INC 1,X       ;  Increment MSB
+ADDZPX: RTS

include/stddef.h02

@@ -6,13 +6,17 @@
 #define TRUE  $FF
 #define FALSE $00 
 
+/* Get Buffer Pointer          *
+ * Returns: Y,X=Buffer address */
+char getdst(); 
+
 /* Get Destination Pointer          *
  * Returns: Y,X=Destination address */
-void getdst();
+char getdst();
 
 /* Get Source Pointer          *
  * Returns: Y,X=Source address */
-void getsrc();
+char getsrc();
 
 /* Retore Destination Pointer */
 void resdst(); 
@@ -38,6 +42,10 @@ void savrxy();
 /* Save Source Pointer */
 void savsrc(); 
 
+/* Set Buffer Pointer        *
+ * Args: &d - Buffer address */
+void setbfr();
+
 /* Set Destination Pointer to Source Pointer */
 void setdss();