;-*-MIDAS-*-
        TITLE    SUDOKU SOLVER

A=1                                    ;Define ACs as universal registers
B=2                                    ;from A to E
C=3
D=4
E=5
X=10                                   ;X and Y are used for indexing
Y=11                                   ;loops etc.
P=17                                   ;Define P as the stack pointer. 

PDLLEN==20                             ;Set the size of the stack to 20 words.
PDL:    BLOCK PDLLEN                   ;Reserve the stack memory
BPTR==440700                           ;Define a byte pointer.

CHTTYO==1                              ;Define a channel for TTY output.

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.
        MOVE  A,[BPTR,,HELLO]          ;Load A with a byte pointer to HELLO.
        PUSHJ  P,OUTSTR                ;Print the out string.
        JRST  DONE                     ;Jump to the end of the program.
OUTSTR: 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.
        .IOT  CHTTYO,B                 ;Print a character.
        JRST  OUT                      ;Jump back to print the next character.
OUTEX:  .IOT  CHTTYO,[^M]              ;Print carriage return and
        .IOT  CHTTYO,[^J]              ;newline characters.
        POPJ  P,                       ;Return from the subroutine.
DONE:   .LOGOUT  2,                    ;Exit point for the program.
HELLO:  ASCIZ  /HELLO WORLD/           ;Define example string.  
END     START