RAM-INIT
RAMdisk initialization
without MEM.SAV.
by Mack McLeod
Do you ever wish you had more RAMdisk space? If so, read on. The DOS 2.5 RAMdisk for the 130XE is initialized by RAMDISK.COM, placing DUP.SYS and MEM.SAV on D8:, and taking up 87 of the precious 499 sectors available. Some applications, though, do not need DUP and MEM. Autorun programs, or those loaded from the DOS menu, may not require memory to be saved. Also, there are several DOS modifications around that place these files under the OS ROM, making the D8: copies useless. The alternative is to manually delete the files after each boot.
For applications that need more RAMdisk space, RAM-INIT is the answer. This program will properly initialize an empty RAMdisk. A basic program is used to create RAMINIT.COM. Delete or rename RAMDISK.COM, then rename RAMINIT.COM to install the function. If you write in assembly, the RAMINIT message may be eliminated by deleting Lines 240 to 410, 1140 to 1250 and 1280. Change the JSR in Line 1130 to a JMP.
The DOS 2.5 address of the RAMdisk initialization filename is $14F1. This contains D:RAMDISK.COM, followed by a $9B. The autorun filename address is $170C. It contains D1:AUTORUN.SYS, followed by a $9B. You may POKE any device prefixed name desired in these locations, as long as the lengths are not exceeded. You will need to use the SAVE DOS FILES option to make the change permanent.
Mack McLeod is an Analyst/Programmer for a major Canadian bank. Even though he works with the largest of mainframes, he's amazed at the power and flexibility of Atari 8-bit machines. He believes they truly provide "Power without the Price." He programs his 130XE primarily in assembly, occasionally in BASIC, and now in C.
| The two-letter checksum code preceding the line numbers here is not a part of the BASIC program. For further information, see the "BASIC Editor II," in issue 47. |
Listing 1.
BASIC listing.
BASIC listing.
OY 160 OPEN #1,8,0,"D:RAMINIT.COM"
ZQ 200 FOR I=1 TO 220
OR 300 READ A: PUT #1,A:NEXT I
BH 400 CLOSE #1:? "
RAMINIT.COM
CREATED" SV 900 DATA 255,255,0,6,207,6,169,0,133,1
9,133,20,169,14,133,85,169,8,133,84,14
1,72,3,169,0
MS 901 DATA 141,73,3,170,169,200,141,68,3
,169,6,141,69,3,169,11,141,66,3,32,86,
228,173,1,211
TH 902 DATA 133,206,169,235,141,1,211,169
0,133,203,169,116,133,204,160,0,185,1
95,6,145,203,200,192,5
CJ 903 DATA 208,246,169,0,145,203,200,192
,10,208,249,169,15,145,203,200,169,255
,145,203,200,192,55,208,249
XI 904 DATA 169,0,145,203,200,169,127,145
,203,200,169,255,145,203,200,192,74,20
0,249,169,0,145,203,200,192
XX 905 DATA 128,208,249,152,24,101,203,13
3,203,165,204,105,0,133,204,162,4,169,
0,168,145,203,200,208,251
LL 906 DATA 230,204,202,208,245,165,206,1
41,1,211,173,10,7,9,128,141,10,7,32,22
4,7,165,20,201,64
XX 907 DATA 144,250,162,0,142,68,3,142,69
,3,142,72,3,142,73,3,169,11,141,66,3,1
69,125,76,86
TA 908 DATA 228,2,243,1,243,1,160,210,193
,205,201,206,201,212,226,2,227,2,0,6
Listing 2.
Assembly listing.
Assembly listing.
0106 ; RAMDISK.COM WITHOUT
0110 ; MEM.SAV, DUP.SYS
0120 ;
0130 ROWCRS = $54
0140 COLCRS = $55
0150 ICCOM = $342
0160 ICPTB = $0B
0176 ICBAL = $344
0180 ICBAH = $345
0190 ICBLH = $349
0200 ICBLL = $348
0210 CIOV = $E456
0220 *=$0600
0230 RAMINI = *
0240 LDA #0 ;INIT,
0250 STA $13 ;CLOCK,
0260 STA $14 ;BYTES.
0270 LDA #14 ;COLUMN ,
0280 STA COLCRS ;FOR MSG.
0290 LDA #8 ;ROW FOR,
0300 STA ROWCRS ;MSG ALSO,
0310 STA ICBLL ;LENGTH.
0320 LDA #0 ;LEN-HI,
0330 STA ICBLH ;ALSO,
0340 TAX ;IOCB NUM.
0350 LDA #MSG&255 ;SET MSG,
0360 STA ICBAL ;ADDRESS,
0370 LDA #MSG/256 ;IN EDITR,
0380 STA ICBAH ;IOCB0.
0390 LDA #ICPTB ;PUT ,
0400 STA ICCOM ;MESSAGE,
0410 JSR CIOV ;WITH CIO.
0420 LDA SD301 ;STORAGE,
0430 STA $CE ;CNTL.
0440 LDA #$ES ;BANK 2
0450 STA $D301 ;MEM CNTL
0460 LDA #29696&255 ;VTOC LO
0470 STA $CB ;POINTER
0480 LDA #29696/256 ;VTOC HI
0490 STA $CC ;POINTER
0500 LDY #0
0510 VLOP1 = * ;FIRST,
0520 LDA MASK,Y
0530 STA ($CB),Y ;SECTION,
0540 INY
0550 CPY #5 ;OF
0560 BNE VLOP1
0570 LDA #0 ;VTOC,
0580 VLOP2 =
0590 STA ($CB),Y ;IN,
0600 INY
0610 CPY #10 ;DATA,
0620 BNE VLOP2 ;MASK.
0630 LDA #$0F
0640 STA ($CB),Y
0650 INY
0660 LDA #$FF
0670 VLOP3 = * ;FREE,
0680 STA ($CB),Y ;SECTORS.
0690 INY
0700 CPY #55
0710 BNE VLOP3
0720 LDA #0 ;DIR.,
0730 STA ($CB),Y ;AND,
0740 INY ;VTOC,
0750 LDA #$7F ;IN,
0760 STA ($CB),Y ;USE.
0770 INY
0780 LDA #$FF ;MORE,
0790 VLOP4 = * ;MORE,
0800 STA ($CB),Y ;EMPTIES.
0810 INY
0820 CPY #74
0830 BNE VLOP4
0840 LDA #0
0850 VLOP5 = * ;FINAL,
0860 STA ($CB),Y ;SEGMENT,
0870 INY ;IN USE.
0880 CPY #128 ;NON-EXIST
0890 BHE VLOP5
0900 TYA ;128 IN A
0910 CLC
0920 ADC $CB ;POINTER,
0930 STA $CB ;AT,
0940 LDA $CC ;DIRECT.
0950 ADC #00
0960 STA $CC
0970 LDX #4 ;X256=1024
0980 LDA #0
0990 DLOP1 = *
1000 TAY ;LOOP 256
1010 DLOP2 = *
1020 STA ($CB),Y ;ZERO,
1030 INY ;WHOLE,
1040 BNE DLOP2 ;DIRECT.
1050 INC $CC ;NEXT,
1060 DEX ;PAGE,
1070 BNE DLOP1 ;LOOP.
1080 LDA $CE ;NORMAL,
1090 STA $D301 ;BANK.
1100 LDA $706 ;DRVBYT
1110 ORA #$80 ;DRIVE 8
1120 STA $70A
1130 JSR $7E0 ;INIT D8:
1140 TIMER LDA $14 ;SHORT,
1150 CMP #$40 ;DELAY FOR
1160 BCC TIMER ;MESSAGE.
1170 LDX #0 ;IOCBO,
1180 STX ICBAL ;SET UP,
1190 STX ICBAL+1 ;FOR PUT,
1200 STX ICBLL
1210 STX ICBLL+1 ;ROUTINE.
1220 LDA #ICPTB ;PUT BUFF,
1230 STA ICCOM ;COMMAND.
1240 LDA #$7D ;CLEAR,
1250 JMP CIOV ;SCREEN.
1260 ;
1270 MASK .BYTE 02,$F3,01,$F3,01
1280 MSG .BYTE "
"1290 .END