diff --git a/src/SUDOKU.MID b/src/SUDOKU.MID
index 4d904f8..abf6d36 100644
--- a/src/SUDOKU.MID
+++ b/src/SUDOKU.MID
@@ -18,11 +18,20 @@ CHTTYO==1                              ;Define a channel for TTY output.
 
 JCL:    BLOCK 30                       ;Reserve space for the command line.
 FNAME1: BLOCK 15                       ;The first part of the file name.
-FNAME2: BLOCK 15                       ;The second file name. 
+FNAME2: BLOCK 15                       ;The second file name.
+
+;Print flags
+;Allows to change the beavihour of the OUTSTR and PUTLN subroutines.
+;The different bits in the word have different meanings.
+;Flags:
+; 001 - SIXBIT: Prints the next character as a SIXBIT char, instead of ASCII, if set.
+PFLAGS: BLOCK 1
 
 START:  MOVE  P,[-PDLLEN,,PDL-1]       ;Initialize the stack.
         .OPEN CHTTYO,[.UAO,,'TTY]      ;Open an output channel on the TTY.
          .LOSE %LSFIL                  ;Gobble up any errors.
+        MOVEI A,001                    ;Initialize the print flag
+        MOVEM A,PFLAGS                 ;to print SIXBIT
         PUSHJ P,GETJCL                 ;Read the command line.
         MOVE  A,[BPTR,,HELLO]          ;Load A with a byte pointer to HELLO.
         PUSHJ P,OUTSTR                 ;Print the out string.
@@ -41,9 +50,9 @@ GETJCL: PUSH  P,A                      ;Save the register A.
         .BREAK 12,[..RJCL,,JCL]        ;Request the JCL.
         MOVE  A,[BPTR,,JCL]            ;Load the command parameters into A.
         MOVE  B,[BPTR,,FNAME1]         ;Pointer to the first file name.
-        PUSHJ TOSIXB                   ;Transfer the first word into FNAME1
+        PUSHJ P,TOSIXB                 ;Transfer the first word into FNAME1
         MOVE  B,[BPTR,,FNAME2]         ;Pointer to the second file name.
-        PUSHJ TOSIXB                   ;Transfer the second word into FNAME2
+        PUSHJ P,TOSIXB                 ;Transfer the second word into FNAME2
         POP   P,B                      ;Restore the B register.
         POP   P,A                      ;Restore the A register.
         POPJ  P,                       ;Return from routine.
@@ -64,13 +73,20 @@ TOSEN:  POP   P,D                     ;Restore the D register.
         POPJ  P,                      ;Return from function.
 
 ;Subroutine to print a string of text on the output.
-; Clobbers A and B.
-OUTSTR: HRLI  A,BPTR                   ;Ensure, A is a byte pointer.
+;Clobbers A.
+OUTSTR: PUSH  P,B                      ;Save register B.
+        PUSH  P,D                      ;Save register D.
+        HRLI  A,BPTR                   ;Ensure, A is a byte pointer.
 OUT:    ILDB  B,A                      ;Load the next byte from A.
         JUMPE B,OUTEX                  ;Exit the routine, if all bytes are done.
+        MOVEI D,PFLAGS                 ;Load the print flags.
+        TRNE  D,001                    ;Test, if the SIXBIT flag is set.
+         ADDI B,40                     ;Convert SIXBIT to ASCII.
         .IOT  CHTTYO,B                 ;Print a character.
         JRST  OUT                      ;Jump back to print the next character.
-OUTEX:  POPJ  P,                       ;Return from the output routine.
+OUTEX:  POP   P,D                      ;Restore D to its original value.
+        POP   P,B                      ;Restore B to its original value.
+        POPJ  P,                       ;Return from the output routine.
 
 ;Subroutine to print an entire line of text, including a line break.
 ;Clobbers A and B.