* KMR_XXXX.PRG * Reset survivable RAM DISK with filename configuration. * Modified by Kevin Millican - October 1989 * This program is in the public domain and may be freely copied. * This Program is a modification of the Public Domain Program ETERNAL, * and was adapted from the ERAMXXXX.PRG variant. The only difference * between this and the ERAMXXXX.PRG program is that the cluster size is * 512 bytes instead of 1024 bytes; particularly useful if you have a lot of * small files held in a ram disk (e.g. help files). * What this modified version does is to READ what drive number and size * the ram disk should be from its own filename. * The search string used by the sfirst gemdos call is "\AUTO\KMR_*.PRG". * For a ram disk 'D' of size 100K you would rename this program to * KMR_D100.PRG, put it in the AUTO folder and cold boot (switch on). * The sfirst search attribute is $37, which searches for files and folders, * so you could rename this program to anything you like and create a * folder or file with and acceptable file name as above. * If an incorrect filename is found or sfirst returns an error or a 0 * size, the program defaults to drive 'D' of size 349K. * Do not forget to install the drive on the desktop and then save the * desktop. * Absolute Default Values default_device equ 3 Default device number ( 3 = D ) default_size equ 349 Default ramdisk size ( 1K units ) magic equ $200 Used to detect restart * Absolute Memory Locations reset_vector equ $004 membot equ $432 memtop equ $436 phystop equ $42E hdv_bpb equ $472 hdv_rw equ $476 hdv_mediach equ $47E drivebits equ $4C4 * DOS Codes Mshrink equ $4A Super equ $20 Fopen equ $3D Fclose equ $3E Fread equ $3F ************************************************************************** program_start movea.l a7,a5 save old stack ptr movea.l #stack,a7 new stack movea.l 4(a5),a5 get address of base page move.l 12(a5),d0 compute length of program add.l 20(a5),d0 add.l 28(a5),d0 add.l #$100,d0 move.l d0,-(a7) size move.l a5,-(a7) mem move.w d0,-(a7) zero move.w #Mshrink,-(a7) return unused memory trap #1 DOS adda.l #12,a7 pop stack clr.l -(a7) set supervisor mode move.w #Super,-(a7) Super trap #1 DOS addq.l #6,a7 pop stack move.l d0,old_ssp save old SSP movea.l #memtop,a4 movea.l #phystop,a5 movea.l (a5),a1 cmpi.w #magic,(a1) beq restart move.w #$2F,-(sp) get current dta trap #1 addq.l #2,sp move.l d0,current_dta save current dta move.l #my_dta,-(sp) set up my dta move.w #$1a,-(sp) trap #1 addq.l #6,sp move.w #$37,-(sp) find this programs own filename move.l #filename,-(sp) move.w #$4e,-(sp) sfirst trap #1 addq.l #8,sp tst.l d0 bne size_error error use default size and device find_device_letter clr.l d0 move.l #my_dta+34,a0 point to device letter in dta move.b (a0),d0 get drive letter from filename sub.b #$41,d0 convert letter to a number bmi get_size if < 0 (A) use default device D cmp.b #15,d0 bhi get_size if > 15 (P) use default device D move.w d0,device_no save device number move.w d0,rd_mediach+2 modify this code move.w d0,rd_bpb+2 with the device number move.w d0,rd_rw+2 *** auto size this program from its own filename * using the 6th, 7th, and 8th, letters only, * but they do not all have to be there * zeroes and leading zeroes are accepted get_size clr.l d7 d7 = letter to convert clr.l d0 d0 = number result move.l #my_dta+35,a0 point to first letter auto_size_loop move.b (a0)+,d7 get first letter from filename beq got_size finish if 0 (end of filename) cmp.b #$2e,d7 compare with "." beq got_size branch if end of filename sub.b #$30,d7 convert letter to number bmi size_error branch if < 0 to error cmp.b #$0a,d7 test for > 9 bge size_error branch if > 9 to error mulu #$000a,d0 multiply by 10 add.w d7,d0 add new result to previous result bra auto_size_loop loop and do other letters got_size asl.l #1,d0 multiply by 2 (smaller clusters) tst.l d0 beq size_error if size = 0 use default 349k bra restore_dta size_error move.l #default_size,d0 file not found, default size restore_dta move.l d0,save_size save the size number move.l current_dta,-(sp) reset current dta move.w #$1a,-(sp) set dta trap #1 addq.l #6,sp move.l save_size,d0 move.w d0,numcl put number of clusters in bpb moveq.l #9,d2 multiplier = 512 not 1024 lsl.l d2,d0 d0 = ramd size in bytes add.l #9216+512,d0 leave space for boot sector * + FAT + root dir + BPB + driver move.l d0,d1 leave at least 128K for user add.l membot,d1 add.l #$20000,d1 cmp.l (a4),d1 bge.s exit sub.l d0,(a4) okay, so reserve memory sub.l d0,(a5) move.l hdv_bpb,old_bpb+2 save hdv_bpb vector move.l hdv_rw,old_rw+2 save hdv_rw vector move.l hdv_mediach,old_mediach+2 save hdv_mediach movea.l #driver,a0 copy drivers to reserved memory movea.l (a5),a1 moveq.l #127,d7 move 512 bytes L4 move.l (a0)+,(a1)+ dbf d7,L4 movea.l reset_vector,a0 force a reset jmp (a0) restart move.l (a5),d1 add.l #rd_bpb-driver,d1 move.l d1,hdv_bpb set hdv_bpb vector move.l (a5),d1 add.l #rd_rw-driver,d1 move.l d1,hdv_rw set hdv_rw vector move.l (a5),d1 add.l #rd_mediach-driver,d1 move.l d1,hdv_mediach set hdv_mediach vector movea.l (a5),a0 mark ramdisk as present adda.l #device_no-driver,a0 move.w (a0),d1 move.w drivebits,d0 bset d1,d0 move.w d0,drivebits exit move.l old_ssp,-(a7) leave supervisor mode move.w #Super,-(a7) trap #1 addq.l #6,a7 clr.w -(a7) exit using Pterm0 trap #1 * Following bytes moved into high memory * ramdisk bios parameter block even driver: recsiz dc.w 512 physical sector size in bytes clsiz dc.w 1 cluster size in sectors clsizb dc.w 512 cluster size in bytes rdlen dc.w 14 root dir length in sectors fsiz dc.w 10 FAT size in sectors fatrec dc.w 12 sector # 2nd FAT start datrec dc.w 36 sector # data start numcl dc.w $01EC number of clusters (filled in above) bflags dc.w 0 rd_mediach cmpi #default_device,4(a7) mediach handler bne old_mediach moveq.l #0,d0 rts rd_bpb cmpi #default_device,4(a7) bpb handler bne old_bpb move.l phystop,d0 rts rd_rw cmpi #default_device,14(a7) rw handler bne old_rw movea.l phystop,a0 adda.l #512,a0 start of ramdisk data area movea.l 6(a7),a1 buffer address moveq.l #0,d1 move.w 12(a7),d1 logical record number moveq.l #9,d0 2^9 asl.l d0,d1 adda.l d1,a0 + ramdisk base = sector address move.w 10(a7),d0 sector count move.l a1,d2 is buffer address odd? btst #0,d2 bne.s L8 yes, then branch btst #0,5(a7) check mode bne.s L6 branch if write exg a1,a0 read, so copy other way round L6 move.w #15,d1 loop 16 times L7 move.l (a1)+,(a0)+ move 32 bytes quickly move.l (a1)+,(a0)+ move.l (a1)+,(a0)+ move.l (a1)+,(a0)+ move.l (a1)+,(a0)+ move.l (a1)+,(a0)+ move.l (a1)+,(a0)+ move.l (a1)+,(a0)+ dbf d1,L7 subq.l #1,d0 decrement count bne.s L6 loop if more sectors to move rts L8 btst #0,5(a7) odd address buffer, use slow move bne.s L9 branch if write exg a1,a0 read, so copy other way round L9 move.w #63,d1 loop 64 times L10 move.b (a1)+,(a0)+ move 8 bytes move.b (a1)+,(a0)+ move.b (a1)+,(a0)+ move.b (a1)+,(a0)+ move.b (a1)+,(a0)+ move.b (a1)+,(a0)+ move.b (a1)+,(a0)+ move.b (a1)+,(a0)+ dbf d1,L10 subq.l #1,d0 decrement count bne.s L9 loop if more sectors to move rts old_bpb jmp 0 vector to old bpb handler old_mediach jmp 0 vector to old mediach handler old_rw jmp 0 vector to old rw handle even device_no dc.w default_device current_dta ds.l 1 save_size ds.l 1 filename dc.b "\AUTO\KMR_*.PRG",0 even my_dta ds.b 44 old_ssp ds.l 1 * saved system stack pointer ds.w 200 * stack stack ds.l 1 end **************************************************************************