HIMEM.DOC FOR HIMEM.COM

WRITTEN BY LARRY KRAEMER  9/15/83

THIS PROGRAM WILL TEST ALL MEMORY FROM 4000H THRU FFFFH.
IT DOES A VERY EXTENSIVE TEST ON ALL MEMORY LOCATIONS AND,
ALSO TESTS THE LOCATIONS NEXT TO THE PRIMARY TEST LOCATION.
THIS PROGRAM SHOULD BE RUN FOR SEVERAL HOURS SO THAT IT WILL
HAVE SEVERAL PASSES THRU THE MEMORY.

                    PROGRAM OVERVIEW FOLLOWS:

THIS PROGRAM LOADS LOW, THEN MOVES ITSELF HIGH.  AFTER CLEARING
THE SCREEN IT DISPLAYS THE INITIAL MESSAGES.  NEXT THE MEMORY
TEST BEGINS WITH LOCATION 4000H THRU FFFFH.

THE SCREEN WILL SHOW A BAD MEMORY LOCATION IN THE UPPER LEFT
CORNER.  IF NO ERRORS OCCUR THERE WILL BE NO HEX ADDRESS IN
THE UPPER LEFT OF THE SCREEN.
THE LOWER RIGHT OF THE SCREEN DISPLAYS AN * WHICH WILL ALTERNATE
WITH A SPACE AS THE PROGRAM COMPLETES ONE PASS THRU MEMORY.
THE SCREEN WILL DISPLAY AN * ON PASSES 1,3,5,7 ETC. AND A SPACE
ON PASSES 2,4,6 ETC.
A COMPLETE PASS THRU MEMORY WILL TAKE APPROXIMATELY 30 MINUTES.

THERE IS A DISPLAY OF THE AREA BEING TESTED IN THE CENTER OF THE
SCREEN.  THE DISPLAY IS IN ASCII, AND THE LEFT BYTE IS THE 
LSB (LEAST SIGNIFICANT BYTE) WITH THE RIGHT BYTE THE MSB.
FOR EXAMPLE THE DISPLAY WILL SHOW FROM 00H THRU FFH IN THE LSB,
WHILE THE RIGHT BYTE WILL BE THE PAGE NUMBER FROM 00H THRU FFH.
THE FORMAT ON THE SCREEN WILL BE BYTE/PAGE.  WITH 64K OF MEMORY
THERE ARE 00H THRU FFH BYTES/00H THRU FFH PAGES.

LET THIS PROGRAM RUN THRU SEVERAL PASSES, AND IF A BIT CHANGES
THE HEX ADDRESS WILL BE DISPLAYED ON THE SCREEN.
LOAD THIS ADDRESS IN BITCHK, AND TEST TO SEE WHICH BIT IS BAD.
THEN THE BAD CHIP CAN BE REPLACED.

NOTE THAT THIS PROGRAM WILL RELOCATE ITSELF WHILE RUNNING, AND
CONTINUES TO TEST THE MEMORY UNTIL REBOOTED.  FOR EXAMPLE WHILE
THE * IS IN THE LOWER RIGHT OF THE SCREEN THE PROGRAM IS SITTING
AT 5000H AND TESTING FROM 6000H THRU FFFFH, THEN IT RELOCATES
ITSELF TO 7000H AND TESTS FROM 4000H THRU 7000H AND A SPACE WILL
BE DISPLAYED ON THE LOWER RIGHT OF THE SCREEN.

THIS PROGRAM MUST BE LOCATED AT 5000H TO START, AND WAS PRODUCED
ON A RADIO SHACK MODEL 1 SO THE SOURCE CODE IS NOT CORRECT
FOR MACRO 80(MAC).  THE PROGRAM IS WRITTEN IN VERY
TIGHT CODE AND NO ATTEMPT WAS MADE TO SHOW THE HEX ADDRESS ON
THE SCREEN WHILE RUNNING SINCE THE LENGTH WOULD INCREASE.

GOOD LUCK AND HOPEFULLY YOU WILL NEVER NEED THIS DIAGNOSTIC.

   LARRY KRAEMER
   R 2 BOX 190
   JACKSON, MO. 63755