/********************************************************\ * IBM Hard Disk driver (using BIOS calls) * * * * Copyright (c) Quantum Software Systems Ltd. 1983 * \********************************************************//* * Define physical Drive characteristics for 20 Mb hard disk */#define SCTRS_PER_TRACK 17#asm "NUM_CYLINDERS = 612"#asm "NUM_HEADS = 4"#asm "SCTRS_PER_TRACK = 17"#define HARD_DISK_EVENT 6/* * Note: Only DMA Channels 1 or 3 may be used */#define READ_BLK 2#define WRITE_BLK 3#define TYPE_HARD 1#asm "TYPE_HARD = 1"#define FBLK_SIZE 512 /*****************************************************\ * Header Information (16 bytes)" * * NOTE: This must be the first file linked * \*****************************************************/#asm " seg 1"#asm " w data TYPE_HARD"#asm " w data "#asm " w data "#asm " w data "#asm " rmb 8"/* * default disk table parameters (16 bytes)" */#asm "b data TYPE_HARD"#asm "b data 0" /* physical drive */#asm "w data 0" /* block offset */#asm "w data 0" /* sectors/disk */#asm "w data 0" /* sectors/cylinder */#asm "b data SCTRS_PER_TRACK" /* sectors/track */#asm "b data 1" /* Sector base */#asm "w data 320h" /* I/O Port */#asm "b data 5" /* Interrupt */#asm "w data NUM_CYLINDERS" /* number of tracks */#asm "b data 0"#asm " seg 3"struct disk_entry { char disk_type; char disk_drv; unsigned blk_offset; unsigned num_sctrs; unsigned sctr_cyl; char sctr_trk; char sctr_base; unsigned ctl_addr; char ctl_int; unsigned num_tracks; char disk_filler[1]; } ;#asm "BLK_OFFSET = 2"#asm "NUM_SCTRS = 4"#asm "SCTR_CYL = 6"#asm "SCTR_TRK = 8"#asm "SCTR_BASE = 9"struct disk_entry *disktab;unsigned drive;unsigned track, head, sector;char mode = 0;unsigned int15_save[2];/* * Initialize the hard disk controller. * disk_init is called when the driver is mounted. */disk_init(dtab,index) { register struct disk_entry *dp; disktab = dtab; dp = disktab; dp += index; init_int(); if(@&dp->sctr_cyl != 0) /* Overridden by MOUNT */ return(0); asm("mov dl,#80h"); asm("mov ah,#8"); /* get disk parameters */ asm("int 13h"); asm("b mov ,dh"); asm("b mov ,ch"); asm("b mov ,cl"); asm("b and ,#3fh"); asm("shl cx"); asm("shl cx"); asm("and ch,#3"); asm("b mov +1,ch"); ++head; ++track; dp = disktab; dp += index; @&dp->sctr_trk = sector; @&dp->sctr_cyl = head * sector; @&dp->num_tracks = track; if(@&dp->num_sctrs == 0) @&dp->num_sctrs = head * track * sector; return(0); }/* * Read a block (512 bytes) from the disk corresponding to * the block number (1..NUM_BLKS) into memory in segment 'seg' * at address 'dbuf' */blk_read(drv, blk, dbuf, seg) { if(map_sector(--drv, blk)) /* results in head, track, sector */ return(-1); mode = READ_BLK; return(r_w_blk(dbuf, seg)); }/* * Write a block (512 bytes) to the disk corresponding to * the block number (1..NUM_BLKS) from memory in segment 'seg' * at address 'dbuf' */blk_write(drv, blk, dbuf, seg) { if(map_sector(--drv, blk)) /* results in head, track, sector */ return(-1); mode = WRITE_BLK; return(r_w_blk(dbuf, seg)); }r_w_blk(dbuf, seg) { asm("mov dl,"); asm("or dl,#80h"); asm("mov dh,"); asm("mov ax,"); asm("mov ch,al"); /* bottom 8 bits of track */ asm("shr ax"); asm("shr ax"); asm("and al,#0c0h"); asm("mov cl,"); asm("or cl,al"); /* top 2 bits of track */ asm("mov al,#1"); asm("mov es,16[bp]"); asm("mov bx,14[bp]"); asm("mov ah,"); asm("int 13h"); asm("mov al,ah"); /* return status */ asm("mov ah,#0"); }/* * Convert block number into head, track, and sector * * Rely on the fact that the extra-segment points to the * data segment of the file system. 'disktab' is the address * of the disk table in that address space. */map_sector(drv, blk)unsigned blk;int drv; { register struct disk_entry *dp; dp = disktab; dp += drv; if(@&dp->disk_type != TYPE_HARD) return(-1); drive = @&dp->disk_drv & 0x07; if(--blk >= @&dp->num_sctrs) return(-1); if(@&dp->sctr_cyl == 0 || @&dp->sctr_trk == 0) return(-1);/* track = blk / @&dp->sctr_cyl; blk -= (track * @&dp->sctr_cyl); /* get remainder */ head = blk / @&dp->sctr_trk; sector = blk - (head * @&dp->sctr_trk) + @&dp->sctr_base;*/ asm("mov ax,BLK_OFFSET[es:di]"); asm("xor dx,dx"); asm("add ax,16[bp]"); asm("adc dx,#0"); asm("div SCTR_CYL[es:di]"); /* assume 16 bit result in AX */ asm("mov ,ax"); asm("mov ax,dx"); /* now div remainder to get head */ asm("xor dx,dx"); asm("mov cl,SCTR_TRK[es:di]"); asm("xor ch,ch"); asm("div cx"); asm("mov ,ax"); asm("mov al,SCTR_BASE[es:di]"); asm("xor ah,ah"); asm("add ax,dx"); /* remainder from last div in DX */ asm("mov ,ax"); return(0); }attach(port) { asm("push 14[bp]"); asm("call attach"); asm("add sp,#2"); }#asm "SIGNAL = 71h"#asm "DISKEVENT = 7"#asm " seg 1"#asm " export trap_int15"#asm "trap_int15:"#asm " cmp ax,#9000h"#asm " je hard_wait"#asm " cmp ax,#9100h"#asm " je hard_int"#asm " abs jmp @cs:"#asm " export hard_wait"#asm "hard_wait:"#asm " push ax"#asm " push es"#asm " push ds"#asm " mov ax,cs"#asm " mov ds,ax"#asm " mov ax,#DISKEVENT"#asm " push ax"#asm " call "#asm " add sp,#2"#asm " mov ax,#40h"#asm " mov es,ax"#asm " b mov es:08Eh,#0ffh ; indicate interrupt occured"#asm " pop ds"#asm " pop es"#asm " pop ax"#asm " iret"#asm "hard_int:"#asm " iret"/* * Initialize the hard disk interrupt and trap int 15 */static init_int() { asm("push es"); asm("cli"); asm("xor ax,ax"); asm("mov es,ax"); asm("mov ax,es:4*15h"); asm("mov ,ax"); asm("mov ax,es:4*15h+2"); asm("mov +2,ax"); asm("mov es:4*15h,#trap_int15"); asm("mov es:4*15h+2,cs"); asm("mov es:4*0F6h,#diskint"); /* catch physical disk interrupts */ asm("mov es:4*0F6h+2,cs"); asm("b in 0a1h"); asm(" and al,#~40h"); asm(" jmp ."); asm("b out 0a1h"); asm("sti"); asm("pop es"); }#asm " seg 1"#asm " export diskint"#asm "diskint: "#asm " push ax"#asm " mov al,#20h"#asm "b out 0a0h"#asm " jmp ."#asm "b out 020h"#asm "signal: "#asm " push bp"#asm " push bx"#asm " push cx"#asm " push dx"#asm " push si"#asm " push di"#asm " push es"#asm " push ds"#asm " mov ax,#DISKEVENT"#asm " int SIGNAL ;signal will not return here" /********************************************************** * Support routines * **********************************************************/#asm " seg 1"#asm ":"#asm " call prologue"#asm " push ds"#asm " push es"#asm " mov ax,ds"#asm " mov es,ax"#asm " mov ax,cs"#asm " mov ds,ax"#asm " push 18[bp]"#asm " push 16[bp]"#asm " call "#asm " add sp,#4"#asm " pop es"#asm " pop ds"#asm " jmp Epilogue"#asm ": "#asm " call prologue"#asm " push ds"#asm " push es"#asm " mov ax,ds"#asm " mov es,ax"#asm " mov ax,cs"#asm " mov ds,ax"#asm " push 22[bp]"#asm " push 20[bp]"#asm " push 18[bp]"#asm " push 16[bp]"#asm " call "#asm " add sp,#8"#asm " pop es"#asm " pop ds"#asm " jmp Epilogue"#asm ": "#asm " call prologue"#asm " push ds"#asm " push es"#asm " mov ax,ds"#asm " mov es,ax"#asm " mov ax,cs"#asm " mov ds,ax"#asm " push 22[bp]"#asm " push 20[bp]"#asm " push 18[bp]"#asm " push 16[bp]"#asm " call "#asm " add sp,#8"#asm " pop es"#asm " pop ds"#asm " jmp Epilogue"#asm "attach:"#asm " mov ax,#4"#asm " int 70h"#asm " ret"#asm ":"#asm " mov ax,#6"#asm " int 70h"#asm " ret"#asm "prologue:"#asm " pop ax ;save return address in ax"#asm " push bp"#asm " push bx"#asm " push cx"#asm " push dx"#asm " push si"#asm " push di"#asm " mov bp,sp"#asm " push ax"#asm " ret ;go back to the function with everything saved"#asm "Epilogue:"#asm " mov sp,bp"#asm " pop di"#asm " pop si"#asm " pop dx"#asm " pop cx"#asm " pop bx"#asm " pop bp"#asm " abs ret"#asm "epilogue:"#asm " mov sp,bp"#asm " pop di"#asm " pop si"#asm " pop dx"#asm " pop cx"#asm " pop bx"#asm " pop bp"#asm " ret"#asm " seg 3"#asm "TEMP:"#asm " rmb 2"#asm "SAVE:"#asm " rmb 2"