RAMTest.s

10 REM > RAMTest/s

20 REM Based on www.willegal.net/appleii/6502mem.htm translation of

30 REM Carl Moser's 6502 RAM test in Issue 1 Compute, 1979.

40 :

50 REM Destructively tests almost all 6502 RAM

60 REM Run on I/O, tests &0E00-&7FFF

70 REM Run on Tube, tests &0500-&F7FF

80 REM On error, prints pp aaaa bb tt

90 REM pp=pass, aaaa=address, bb=byte from ram, tt=test byte

100 :

110 REM On completion, language memory zeroed and language re-entered

120 :

130 OSRDCH=&FFE0:OSNEWL=&FFE7:OSWRCH=&FFEE:OSBYTE=&FFF4

140 DIM mcode% &180

150 :

160 start=&80:end=&82:addr=&84

170 test=&86:pass=&87

180 :

190 FOR P=0 TO 1

200 P%=&400:O%=mcode%

210 [OPT P*3+4

220 .exec%

230 JMP go%:BRK:BRK:BRK \ Header identifies

240 EQUB &42:EQUB copy-exec% \ this as 6502 code

250 EQUB &10:EQUS "RAMTEST"

260 EQUB &00:EQUS "1.00 (15 Feb 2010)"

270 .copy

280 EQUB 0:EQUS"(C)J.G.Harston":EQUB 0

290 :

300 .go%

310 LDA #&82:JSR OSBYTE \ What side of the Tube are we on?

320 LDA #&0E:LDX #&80 \ start, end for I/O

330 INY:BEQ setlimits

340 LDA #&05:LDX #&F8 \ start, end for Tube

350 .setlimits

360 STA start+1:STX end+1 \ Set memory test limits

370 LDA #0:TAY \ Initial test byte=&00

380 \STA start+0:\STA end+0

390 .loop0

400 STA test

410 :

420 \ Test type in Y

430 \ 0 = all zeros

440 \ 1 = all ones

450 \ 2 = move 1s up through bytes

460 \ 3 = move 0s up through bytes

470 \ 4 = low byte of address

480 \ 5 = high byte of address

490 \ 6 = all zeros again

500 :

510 \ Test all memory with test byte specified by Y

520 \ ---------------------------------------------

530 .loop1

540 \LDA start+0:\STA addr+0

550 LDX #0:STX addr+0 \ Point to start of memory to test

560 LDA start+1:STA addr+1

570 :

580 \ On pass 4 and 5 use address as test byte

590 \ ----------------------------------------

600 .loop2

610 LDA addr+0:CPY #4:BCC testbyte \ pass<4, use current test byte

620 BEQ setbyte \ pass=4, use low byte of address

630 LDA addr+1:CPY #6:BCS testbyte \ pass=5, use high byte of address

640 .setbyte

650 STA test

660 :

670 \ Test memory with test value

680 \ ---------------------------

690 .testbyte

700 LDA test \ Get test byte

710 STA (addr,X):LDA (addr,X) \ Store test byte and fetch it back again

720 CMP test:BEQ no_error \ Fetched value didn't match stored value

730 :

740 \ Error occured, report it

750 \ ------------------------

760 PHA \ Save test byte

770 TYA:JSR PrHex \ Output pass number

780 LDA addr+1:JSR PrHexSpc

790 LDA addr+0:JSR PrHex \ Output address

800 PLA:JSR PrHexSpc \ Output actual byte

810 LDA test:JSR PrHexSpc \ Output test byte

820 JSR OSNEWL

830 :

840 .no_error

850 INC addr+0:BNE P%+4:INC addr+1 \ Step to next address

860 \LDA addr+0:\CMP end+0:\BNE loop2

870 LDA addr+1:CMP end+1:BNE loop2 \ Loop to test memory

880 :

890 \ All memory tested, prepare for next pass

900 \ ----------------------------------------

910 CPY #1:BCC next0:BEQ next1

920 CPY #3:BCC next2:BEQ next3

930 CPY #5:BEQ next5:BCS done

940 : \ Drop through to INC Y and loop back

950 .next0

960 DEC test:INY:BNE loop1 \ test byte=&FF, retest memory

970 .next1

980 STY test:INY:BNE loop1 \ test byte=&01, retest memory

990 .next2

1000 ROL test:BCC loop1 \ Move set bit up, retest memory

1010 LDA #&FE:STA test:INY:BNE loop1 \ Set bits done, test byte=&FE, retest memory

1020 .next3

1030 ROL test:BCS loop1 \ Move clear bit up, retest memory

1040 .next5

1050 LDA #0:INY:BNE loop0 \ Clear bits done, do address bytes

1060 :

1070 .done

1080 LDA #ASC"O":JSR OSWRCH

1090 LDA #ASC"K":JSR OSWRCH

1100 JSR OSRDCH:JSR OSNEWL \ Wait for a keypress

1110 LDA #252:LDY #255 \ X will still be &00

1120 JSR OSBYTE:LDA #142:JMP OSBYTE \ Re-enter current language

1130 :

1140 .PrHexSpc

1150 PHA:LDA #ASC" ":JSR OSWRCH:PLA \ Print a leading space

1160 .PrHex

1170 PHA:LSR A:LSR A:LSR A:LSR A

1180 JSR PrNyb:PLA

1190 .PrNyb

1200 AND #15:CMP #10:BCC P%+4:ADC #6

1210 ADC #ASC"0":JMP OSWRCH

1220 ]:NEXT

1230 PRINT"*SAVE RAMTEST ";~mcode%;" ";~O%;" ";~exec%;" ";~exec%