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* One from the Vault is a collection of frequently requested, useful or just
plain interesting past posts sent to comp.binaries.cbm, as archived by the
moderators. If you have a request, please send it to the address in the
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From: Jason Petersen <petersenj@NOyahooSPAM.com>
Reply-to: Jason Petersen <petersenj@NOyahooSPAM.com>
X-Original-Posting-Date: Fri, 08 Nov 2002 03:59:16 GMT

[ Cleaned up slightly -- Cameron Kaiser ]

memtest.prg -- A RAM testing program for the C64. -- v1.00
(c) Jason Petersen 2002 ===============================================================================

Usage:
------
LOAD"MEMTEST.PRG",dv,1
SYS820

This program will repeatedly test RAM from $0800 to $ffff (62 KB) by writing a value to a location, checking that the location holds the written byte, then moving to the next memory location. When $ffff is reached, the test will start over at $0800, alternating between a fill pattern of $ff and $00. The screen border will flash after each cycle to indicate progress. The test may be aborted at any time by pressing the space key.

If there is any discrepancy between the value written and the value read, an error is generated. The error will be displayed on the screen in decimal as: (memory location) (value written) (value read)

For Example:

ERRORS:
49152 255 251

If many errors are being generated, the space key may need to be held down for a few seconds before the program terminates. Have patience and the program will stop when the current page is finished.

If there are many errors and the screen is scrolling, try holding down the CTRL key to slow it down.

Why test only 62 KB? The program has to fit in memory somewhere! It sits around the tape buffer from $0334 to $03fe. The screen is from $0400 to $07e8. Trust me, if there are RAM problems in locations $0000 to $0333 you will have no
need of this program, since the computer probably won't work. :) It would be easy to make this a 63 KB tester by checking the range $0400 - $07ff as well, but then it would be difficult to read any errors since the screen would be overwritten.

You can get the latest version of memtest from:
http://thisoldcomputer.com
Send comments to petersenj@NOSPAMyahoo.com, flames to /dev/null.

Jason

begin 644 memtest.prg M-`,@PP,@/0-,X@.B`*#XK?(#G0`(O0`(S?(#\`,@C@/HT.P@ZP.M`=PJ*BHJ ML`%@(.0#[D8#[DD#B-#3J0#-\@/0`JG_C?(#J0B-1@.-20,@ZP/N(-`@Y`-, M/0.-\P..]`,@ZP.M1@,@S;VI("#2_ZD`KO(#(,V]J2`@TO^I`*[S`R#-O:D- M(-+_(.0#KO0#8*(`O?4#\`8@TO_HT/6I_XWR`ZD(C48#C4D#>"#D`V!88*4! K*?B%`6"E`0D'A0%@_P``DT524D]24SH-`-.]/-.=.=.M/--M.]-M.-/=/:4!
`
end
--
Cameron Kaiser * ckaiser@floodgap.com * posting with a Commodore 128
Floodgap Systems: http://www.floodgap.com/
personal page: http://www.cameronkaiser.com/

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