开发学院软件开发汇编语言 汇编仿FDISK及PQMAGIC列出分区逻辑盘符的prw.asm实... 阅读

汇编仿FDISK及PQMAGIC列出分区逻辑盘符的prw.asm实现

 2007-11-13 09:31:21 来源:WEB开发网   
核心提示:(5) 例:笔者486,在pri_ds上,装ST32140A驱动器(2012M),在sec_ds上,装QUANTUM(514M).(5.1) 80h上,现有vol=6的DOS活跃主分区(FAT16B,1299M),vol=6的主分区(F16B,39.4M),vol=17h的非DOS分区(HiddenNTFS,574.9

 
 (5) 例:
 
 笔者486,在pri_ds上,装ST32140A驱动器(2012M),在sec_ds上,装QUANTUM(514M).
 
 (5.1) 80h上,现有vol=6的DOS活跃主分区(FAT16B,1299M),vol=6的主分区(F16B,39.4M),vol=17h的非DOS分区(HiddenNTFS,574.9M),vol=5的扩展分区,其托4个逻辑分区,按链上次序是:
 
 vol=0bh的DOS主分区(F32,35.4M),vol=83h的非DOS分区(LINUX_Ext2,19.7M),vol=1的DOS主分区(Unfmt,3.9M),vol=6的主分区(41.3M)
 
 (5.2) 81h上,现有vol=82h的非DOS分区(L_Swap,3M),vol=11h的非DOS分区(Unfmt,3M),vol=6的活跃主分区(472.5M),vol=0fh的扩展分区,其托4个逻辑分区,按链上次序:
 
 vol=82h的非DOS分区(L_Swap,10.8M),vol=1的主分区(F12,8.8M),vol=7的非DOS分区(N,9,8M),vol=1的主分区(U,7.8M).
 
 从98软盘启动,F$,P$,列出这些分区的盘符及容:
 
 C:1299M
 D;472.5M
 E:35.4M
 F:3.9M
 G:41.3M
 J:39.4M
 H:8.8M
 I:7.8M
 
 (6) prw功能
 
 命令行是prw.exe [foo1]
 
 初见:
 b(pb),p(arti),r(ead sec to foo/stdout),w(rite foo to sec),v(xd w)
 
 命令键b,p,r,w,v:
 
 (6.1) b,显subBPB
 (6.2) p,显分区盘编号,逻辑盘符,BootON值,vol值,Front值,In值,例如
 
 80,C:,Boot:80,FAT:06,Front:0000003f,In:00101661
 
 (6.3) r,读软硬盘内容到新建foo,或stdout
 (6.4) wv,写已存foo到软硬盘.v多依VxD,胜v86禁13h写.算法,见"(8) 论V86下,直寻硬盘扇区,只能靠VxD"
 
 rwv,用旧FCB式,读源F16,F32,写F16.逐扇有结果I/O,直至出错或事成.
 
 欲读80h的MBR到文件b:d,先发:
 
 prw b:d
 
 再答r,界面:
 
 drv(00~01,80~83)80
 0~cyl(0029)
 0~hd(1f)
 1~sec(3f)
 0~lba(00014abf)
 c(hs),l(ba)l
 0~lba(00014abf)00000000
 0~cyl(0000)
 0~hd(00)
 1~sec(01)
 0~lba(00000000)
 1~total(ffff)0001
 
 事成/中止,d长度512/0.
 
 v86时,改向buf文符到F32的文件g,可发prw c:u>g
 
 (7) 文
 NIBSZ=8     ;8个hex数
 
 nibasc     macro
         local  nq
 
     add    al,48
         cmp       al,10+48
         jb       nq
     add    al,97-48-10
 nq:
         endm
 
 alasc      macro
     mov    ah,al
         and       al,15
         nibasc
         xchg      ah,al
     rept    4
     shr    al,1  高nibble
     endm
         nibasc
         stosw
     endm
 
 axasc  macro 
       push ax
       mov al,ah  转ah
       alasc
       pop ax  转al
       alasc
     endm
 
 d segment
 buf   db   511 dup(0)  放MRB.全囿V86页(4k),buf长1023,囿DMA_64k
 buf511  db  0    老buf尾
 
 info_sz   dw 26 ;min sz of info buf  新buf
 flags     dw 0  ;flags
 cylinders0   dw 0  ;number of cylinders on disk
 cylinders1   dw 0
 heads00    db 0  ;number of heads on disk
 heads01     db 0
 heads1     dw 0
 s1track00 db 0  ;number of sectors per track
 s1track01 db 0
 s1track1 dw 0
 sectors    dq 0  ;number of sectors on requested disk
 sector_sz  dw 0  ;number of bytes per sector 
        db   511-26 dup(0) ;新buf
 
 FAT db 13,10,'0~0eh:'
 db 13,10,'?OS,F12/Unfmt,,,F16/U_,EXtend,F16B,NTFS,,,,F32,F32_13X,,F16'
 db 13,10,'11,14,16,17,1b:(Hidden)'
 db 13,10,'F12/U_,F16,F16B,N,F32$'
 
 .view  db  '0000,cx='
 viewcx  db  '13EX,dx='
 viewdx  db  'tend'
 CR    db 13,10,36
 
 extblk db 16,0  分区表16字节用
 sec_tot dw 1
 buf_off dw buf ;buf偏移
 buf_seg dw SEG buf
 lbal  dw 0  ;lba低双字低字
 lbah  dw 0  ;lba低双字高字
     dd 0  ;lba高双字
 
 cmd_p  db 'b(pb),p(arti),r(ead sec to foo/stdout),w(rite foo to sec),v(xd w)$';rwv用
 
 logi_p  db 13,10,'logi_drv(A:=01)$'
 subBPB  db 13,10,'SV_sec:'
 SV_sec  db 0,'000,FATs:'  向foo读
 FATs  db '00,sec_per_FAT:'
 sec1FAT  db '0000$'
 
 drv_p  db 13,10,'drv(00~01,80~83)$'    ;扩展i13用
 mod_p  db 13,10,'c(hs),l(ba)$'      ;dosext,nondos用
 
    db 13,10
 from80 db '8?,'
 logidrv db 'C:,Boot:'
 Boot  db '?0,FAT:'
 volume db '06,Front:'
 Front_h dw ?,?  又做总扇数
 Front_l db '0000,In:'
 In_h  dw 0,?  又做当前扇号
 In_l  db '0000$'
 
 cyl_p  db 13,10,'0~cyl('
 cyl_p1 db  '????)$'
 
 hd_p  db 13,10,'0~hd('
 hd_p1 db   '??)$'
 
 sec_p  db 13,10,'1~sec('
 sec_p1 db  '??)$'
 
 lba_p  db 13,10,'0~lba('
 lbah_p1 db  '????'
 lbal_p1 db  '????)$'
 
 total_p db 13,10,'1~total(ffff)$'
 
 scr_p  db   '^C,f(ast),n(ext)$'
 
 primk db   1,4,6,11,12,14  主分区标识
 primksz=$-primk
 extmk db   5,15    扩展分区标识
 extmksz=$-extmk
 
 stk1  dw  NIBSZ/4 dup(0) ;INnib栈
     db   32
 rowasc db (2+1)*16 dup(32),36
 
 kbd   db NIBSZ+1 ;键盘buf
 kbd1   db 67  parti用
 kbd2  db NIBSZ+1 dup(0)
 
 fcbdrv db 0
 fcbnam db 8 dup(32)
 fcbext db 3 dup(32)
 
 fcbblk dw 0
 fcbrsz dw 512
 
 fcbsz db 4 dup (4)  已占分区表号,4硬盘*1字节,parti用
 fcbdat dw 0
 
 fcbdos1 db 10 dup(0)
 fcbrno db 0
 
 entry  label  dword  ;fcbrand
 entrydi dw   0
 entryes dw   0
 
 media_h db 0  ;头数
 media_c dw 0  ;柱数
 s1cyl  dw 0  ;扇数/柱
 s1track db 0  ;扇数/道
 
 drv   db 0  ;输入
 hd   db 0
 cyl   dw 0
 sec   db 0
 
 hextbl db  '0123456789abcdef'
 d ends
 
 c segment
     assume cs:c,ds:d,es:d
 
 @    proc  far
 
   push  ds     ;为exe返回
   xor  ax,ax      压cd20的psp:0
     push ax
 
     mov ax,d
     mov es,ax
 
     cmp   byte ptr ds:[5dh],32  缺foo
   je  @0
 
     inc   es:SV_sec
     mov cx,1+8+3
   mov   si,5ch  sh复制盘符+大写8.3名到5ch
   lea   di,fcbdrv
     rep movsb  es:di=ds:si的盘符+8.3
 
 @0:  mov ds,ax
 
     mov ah,9
     lea dx,cmd_p  ;问命令
     int 21h
 
     mov   ah,1    
     int   21h
 
   cmp  al,'b'
     je   b
     jmp  p
 
 b:   mov kbd,2 + 1
     lea dx,logi_p  问逻辑盘
     Call INnib
 
   mov ax,440dh
   mov cx,860h  传统及扩展13,共享BPB前12字节
   lea dx,buf
   int 21h
 
     mov ax,word ptr buf[7+3]
     lea di,SV_sec
     axasc
 
   mov al,buf[7+5]
     lea di,FATs
     alasc
 
     mov ax,word ptr buf[7+11]
   or ax,ax
   jnz bo
 
     mov ax,word ptr buf[7+25]
 
 bo:   lea di,sec1FAT
   axasc
 
   mov ah,9
   lea dx,subBPB
   int 21h
   ret
 
 p:   cmp  al,'p'
     jne r
 
   mov ah,9
     lea dx,FAT
   int 21h
 
     lea bx,buf
 
     mov   dx,80h  扩展i13,可兼容传统
     Call dospri
     mov mod_p,dl
 
     mov   dl,80h
     Call dosext
                
     mov lbal,0
     mov lbah,0
     
     mov dl,80h
     Call nondos 
     ret
 
 r:  mov   cmd_p,al
 
   cmp   al,'r'
     je rwv
 
     cmp   al,'w'
     je rwv
 
     cmp   al,'v'
     je   v
 
   ret
 
 v:   mov   ax,1684h  ;func
     mov   bx,3180h  ;接口ID
     int   2fh
 
     mov   ax,es    ;es:di=V86口cs:ip
     or   ax,di
     jnz   v1      
   ret      es,di全0,失败
 
 v1:   mov entrydi,di
     mov entryes,es
     push ds
     pop es
 
 rwv:  mov kbd,2 + 1
     lea  dx,drv_p  问磁盘
     Call INnib
 
     mov drv,bl
   mov dl,bl    驱动器
     
   test bl,80h
     jne rwv1
 
   xor dh,dh    头
     Call f_geo
     jmp rwv2
 
 rwv1:  Call h_geo
 
 rwv2:  test media_h,255
     jne rwv3
     ret
     
 rwv3: mul s1cyl
 
     sub ax,1    ;lba始于0,可写CF
     sbb dx,0
 
     mov lbal,ax
     mov lbah,dx
 
     Call lba2chs
     Call rng
 
     mov ah,9        ;问寻扇
     lea dx,mod_p
     int   21h
 
     mov ah,1
     int   21h   
     cmp   al,'c'
     je rwv4
 
     mov kbd,8 + 1
     lea dx,lba_p
     call  INnib    ;问lbah,lbal
     mov lbal,bx
 
     mov ax,stk1
     mov lbah,ax
 
     Call lba2chs
     jmp rwv5
 
 rwv4:mov kbd,4 + 1
     lea   dx,cyl_p  ;问柱面号
     Call INnib
     mov cyl,bx
 
     mov kbd,2 + 1
     lea   dx,hd_p   ;问头号
     Call INnib
     mov hd,bl
 
     mov kbd,2 + 1
     lea   dx,sec_p  ;问扇号
     Call INnib
     mov sec,bl
 
     Call chs2lba
 
 rwv5:Call rng     ;显出立体,线性值
 
     mov kbd,4 + 1
     lea   dx,total_p ;问总计
     Call INnib
 
     mov Front_h,bx
 
     lea dx,fcbdrv ;指向fcb
 
     mov   ah,15    ;open for w,v
     cmp cmd_p,'r'
     jne rw1
 
     test SV_sec,1  向foo读
     jz rw2
 
     mov   ah,16h   ;create or trunc for r,软盘启动,拒存取F32盘
 rw1:  int   21h  改fcbdrv为3=C
     
   or   al,al    al为0,成功
     jnz   rw7
 
     mov fcbrsz,512    重置
 
 rw2:  mov    ax,600h    al=clr
     mov    bx,700h    bl=page
     xor    cx,cx
     mov    dx,184fh  25*80
     int    10h      cursor grow 0,24
 
     mov   ah,1ah   ;DTA
     lea dx,buf
     mov bx,dx       ;I/O数据区
     int   21h
 
 rw3:  test  Front_h,65535
     jz rw6
 
    cmp cmd_p,'r'
     jne rw4
 
     mov ax,201h
     mov dl,drv
     Call rw1by1
   je rw6
 
   Call scr
 
     test SV_sec,1    ;向foo读
     jz rw5
 
   mov   ah,15h   ;强制write
     lea dx,fcbdrv
     int   21h
     jmp rw5
 
 rw4:  mov   ah,14h   ;read
     lea dx,fcbdrv
     int   21h
    
     Call scr
 
     mov ax,301h
     mov dl,drv
     Call rw1by1
     je rw8       ;出错,关闭
 
 rw5:  add lbal,1
     adc lbah,0
 
     inc In_h
     dec Front_h
     jmp rw3
 
 rw6:  test SV_sec,1  向foo读
   jnz rw8
 
 rw7:  ret
 
 rw8:  mov   ah,16    ;close
     lea dx,fcbdrv
     int   21h
 
     ret
 @    endp
 
 dospri proc        ;统计硬盘数,查DOS主分区
 dospri0:cmp dl,80h+4
     je dospri7
 
     mov   ax,201h   ;测硬盘
     mov cx,1
     int   13h
     jc dospri7
 
     mov bp,4*16    
 
     xor   si,si    ;分区表,占4*16字节
 dospri1:cmp si,4*16
     je dospri4
 
     mov al,buf[1beh+si+4]    取vol
     mov cx,primksz     是主分区?
     lea di,primk
     repne scasb
     jne dospri3
 
     test byte ptr buf[1beh+si],80h ;取BootON
     jnz dospri2
 
     cmp bp,4*16
     jnz dospri3
     
 dospri2:mov bp,si         ;暂选首现主分区
     jnz dospri5
 
 dospri3:Add si,16
     jmp dospri1
 
 dospri4:cmp bp,4*16
     je dospri6
 
 dospri5:mov si,dx
     sub si,80h
 
   mov ax,bp
   div extblk   
     mov fcbsz[si],al  标占分区表项号
 
     mov al,kbd1
     mov logidrv,al
     inc kbd1
 
   Call Show
 
 dospri6:inc dl        ;读下块硬盘
     jmp dospri0
 
 dospri7:ret
 dospri endp
 
 pri_non proc
     mov logidrv,32
 
     mov cx,primksz
     lea di,primk
     repne scasb
     jne non       ;不赋非DOS分区盘符
 
     mov logidrv,94    ^符
 
     mov al,kbd1
     cmp al,'Z'
     ja non
 
     mov logidrv,al
     inc kbd1
 
 non:  Call Show
     ret
 pri_non endp
 
 dosext proc        查DOS扩展分区
 dosext0:cmp dl,mod_p
     je dosext4
 
     mov ax,201h
     mov cx,1
     int 13h
       
     xor bp,bp
 dosext1:cmp bp,4*16
     je dosext3
 
     mov al,buf[1beh+bp+4]
     mov cx,extmksz       是扩展分区?
     lea di,extmk
     repne scasb
     jne dosext2
 
     push bx
     push dx
     Call h_geo
     pop dx
     pop bx
 
     mov   ax,word ptr buf[1beh+bp+8]  ;Front low
     mov entrydi,ax  基址
     mov lbal,ax
 
     mov   ax,word ptr buf[1beh+bp+10] ;Front high
     mov entryes,ax
     mov lbah,ax
 
     xor bp,bp    ;为show
     Call chain      
     jmp dosext3
 
 dosext2:Add bp,16
     jmp dosext1
 
 dosext3:inc dl
     jmp dosext0
 
 dosext4:ret
 dosext endp
 
 h_geo proc
     mov   ah,41h
     mov   bx,55aah  ;测BIOS支持i13_X
     int   13h
     jc   h_geoo
 
     cmp   bx,0aa55h  再核
     jne   h_geoo
 
     test cx,1       ;支持41~44,47~48第1子集?
     jz h_geoo
 
   mov ah,48h      取尺寸
     lea si,info_sz
     int 13h
 
     mov   al,heads00     ;头数
     or    al,al
     jz    h_geoo  无效info包
 
     mov   media_h,al
     inc drv_p  启扩展
 
     mov   ah,s1track00 ;每道扇数
   mov  s1track,ah
 
     mul ah
     mov s1cyl,ax      每柱面扇数
 
     mov   ax,cylinders0   ;柱面数
     mov   media_c,ax
   ret
 
 h_geoo:  mov ah,8  取尺寸
     int 13h
     jc h_geoq
 
     inc dh
 
     mov al,dh
     mov   media_h,al ;头数
 
     mov s1track,cl
     and s1track,63   每道扇数
 
     mul s1track
     mov   s1cyl,ax  ;每柱面扇数
 
    xchg ch,cl
    rol ch,1
      rol ch,1
    and ch,3
 
     mov ax,cx
     inc ax
     mov   media_c,ax ;柱面数
 
 h_geoq:  ret
 h_geo endp
 
 chain   proc        ;处理链
 chain0: mov ax,201h
     Call rw1by1
 
     mov al,buf[1beh+4]
     call pri_non
 
     test buf[1beh+16+4],255     ;0,5,15之1
     je chain1
 
     mov ax,word ptr buf[1beh+16+8]
     add ax,entrydi         ;加基址entrydi
     mov lbal,ax
 
     mov ax,word ptr buf[1beh+16+10]
     adc ax,entryes         ;加基址entryes
     mov lbah,ax
 
     jmp chain0
 chain1: ret
 chain  endp
 
 nondos  proc        查未占过盘符的DOS主分区及非DOS分区
 nondos0:cmp dl,mod_p
     je nondos4
 
     mov ax,201h
     mov cx,1
     int 13h
 
     mov bp,dx
     sub bp,80h    
   
    mov al,fcbsz[bp]  取已占分区表号
    mul extblk
    mov fcbdat,ax
 
     xor   bp,bp
 nondos1:cmp bp,4*16
     je nondos3
 
    cmp bp,fcbdat
     je nondos2       ;已占
 
     mov al,buf[1beh+bp+4]
 
     test al,255    不理闲置分区
     jz nondos2
 
     mov cx,extmksz     ;略扩展分区
     lea di,extmk
     repne scasb
     jz nondos2
 
     call pri_non
 
 nondos2:Add bp,16
     jmp nondos1
    
 nondos3:inc dl
     jmp nondos0
    
 nondos4:ret
 nondos endp
 
 show  proc  ;分区信息
     push dx
 
     and dl,3      盘号80~83
     add dl,48
     mov from80[1],dl
 
     mov Boot,48      多数为0
     test buf[1beh+bp],80h
     jz show0
     mov Boot,56
 
 show0:  mov al,buf[1beh+bp+4] ;显vol
     lea di,volume
     alasc
 
     mov   ax,word ptr buf[1beh+bp+8]  ;取Front low
     add ax,lbal          ;为chain而加
     pushf
     lea di,Front_l
     axasc
     mov   ax,word ptr buf[1beh+bp+10] ;Front high
     popf
     adc ax,lbah          ;为chain而加
     lea di,Front_h
     axasc
 
     mov   ax,word ptr buf[1beh+bp+12] ;取In low
     lea di,In_l
     axasc
 
     mov    ax,word ptr buf[1beh+bp+14] ;In high
     lea di,In_h
     axasc
 
     mov ah,9
     lea dx,from80
    sub dx,2
     int 21h
 
     pop dx
     ret
 Show endp
 
 rw1by1 proc      读/写1扇
     test drv_p,1  13=传统
     jnz rw1by11
 
    xor   al,al    不校验写
     or   ah,40h
     lea   si,extblk  ;扩展块
     jmp rw1by12
 
 rw1by11:push ax
     push dx
     call lba2chs
     pop dx
     pop ax
 
     call cxdh
 
     mov word ptr viewcx,cx
     mov word ptr viewdx,dx
 
 rw1by12:cmp cmd_p,'v'
     je rw1by13
 
   int  13h
   ret      遗c
 
 rw1by13:Call [entry]
 
     cmp  bp,4096  VxD按(8.3)返bp值
     jae   rw1by14
 
     push bx
 
     add   bx,bp    ;使bx,bx+511在4k内
   mov  buf_off,bx  扩展i13
 
     push cx
   push si
 
     lea   si,buf511  ;原buf尾
 
     mov di,si
     add   di,bp    ;新buf尾
 
     std         ;从后向前移1扇
     mov cx,256
     rep movsw
     cld
 
   pop si
     pop cx
 
     Call [entry]
 
     pop bx
   mov  buf_off,bx  扩展i13
 
   cmp   bp,4096
 rw1by14:je  rw1by15
 
   cmp  bp,1010h
   jne  rw1by16
 
   xor ah,ah
     Call [entry]    释它页
 
 rw1by15:cmp al,al  置zr
 rw1by16:ret
 
 rw1by1 endp
 
 f_geo proc
     lea   bx,buf   ;缓区
     mov   cx,1    ;0:0:1(chs)引导扇
 
 f_geo0:   mov   ax,201h   ;读1扇
     int   13h     ;读11起的bios参数块
     jc    f_geo0   ;换盘
 
   mov   al,[bx+26] ;偏移26:头数
     mov media_h,al
 
     mov   ah,[bx+24] ;偏移24:每道扇数
     mov s1track,ah
 
     mul ah
     mov   s1cyl,ax  ;每柱面扇数
     
     mov   ax,[bx+19] ;偏移19:总扇数
     xor   dx,dx    ;高字
 
     div s1cyl
 
     mov   media_c,ax ;柱面数
   ret
 f_geo endp
 
 rng proc
     mov   ax,cyl   ;当前柱面
     lea di,cyl_p1
     axasc
 
     mov   al,hd    ;当前头
     lea di,hd_p1
     alasc
 
     mov   al,sec   ;当前扇号
     lea di,sec_p1
     alasc
 
     mov   ax,lbah   ;当前lba高字
     lea di,lbah_p1
     axasc
 
     mov   ax,lbal   ;当前lba低字
     lea di,lbal_p1
     axasc
 
     mov ah,9
     lea dx,cyl_p
     int   21h
 
     lea dx,hd_p
     int   21h
 
     lea dx,sec_p
     int   21h
 
     lea dx,lba_p
     int   21h
 
     ret
 rng endp
 
 scr proc
     mov    cx,16  字符数/row
 
     xor   si,si
 
 scr0:  push  bx
     mov    ah,2
     xor    bh,bh  pg
     xor    dx,dx  dh=row
     int    10h
     pop    bx
 
     lea dx,.view
 
     test si,256
     jz scr1
     jmp scr3
 
 scr1:  mov di,dx
     mov  ax,In_h    现扇号
     axasc
 
     test drv_p,1
     jnz scr2
     jmp scr3
 
 scr2:  lea di,viewcx
     mov  ax,word ptr [di]
     axasc
 
     lea di,viewdx
     mov  ax,word ptr [di]
     axasc
 
 scr3:  mov ah,9
     int 21h
 
 scr4:  mov ax,si
     lea di,stk1
     axasc
 
     lea bp,rowasc
 
 scr5:  mov al,[bx+si]
 
     mov di,si
     and di,15
 
     mov FAT[di],46
 
     cmp al,32
     jb scr6    
 
     mov FAT[di],al
 
 scr6:  mov di,bp
     alasc
 
     Add bp,2+2-1
 
     inc si
     test si,15
     jne scr5
 
     mov ah,9  行的hex
     lea dx,stk1
     int 21h
 
     push bx
     mov ah,64  行的asc及汉字
     mov bx,1
     lea dx,FAT
     int 21h
     pop bx
 
     mov ah,9
     lea dx,CR
     int 21h
 
     test si,255
     je scr7
     jmp scr4
 
 scr7:  cmp scr_p,'f'
     je scr8
 
     mov ah,9
     lea dx,scr_p
     int 21h
 
     mov ah,1    ;按1键
     int 21h
 
     cmp al,'f'
     jne scr8
 
     mov scr_p,al
 
 scr8:  test si,511
     je scr9
     jmp scr0
 
 scr9:  ret
 scr   endp
 
 cxdh proc
     mov   dh,hd    ;头号
 
     mov   cx,cyl   ;柱面号
     xchg cl,ch
 
     ror cl,1
     ror cl,1
   and cl,not 63
 
     or   cl,sec   ;低6位扇号
     ret
 cxdh endp
 
 lba2chs proc
     mov ax,lbal
     mov dx,lbah
 
     div   s1cyl    ;柱面号
     mov cyl,ax
 
     mov ax,dx
     div s1track
 
     mov   hd,al    ;头号
     inc ah
     mov   sec,ah   ;扇号
 
     ret
 lba2chs endp
 
 chs2lba proc
     mov   ax,cyl   ;柱面号
     mul s1cyl
 
     mov lbal,ax
     mov lbah,dx
 
     mov   al,s1track ;每道扇数
     mul hd
 
     Add lbal,ax
     adc lbah,0
 
     mov   al,sec   ;此处,低6位扇号
     dec al
    cbw
 
     Add lbal,ax
     adc lbah,0
 
     ret
 chs2lba endp
 
 INnib  proc    ;kbd限长nib入kbd2.转后入stk1,低字还入bx
 INnib0: mov ah,9
     int 21h
 
     push dx
     inc ah   ;回车才收
     lea dx,kbd
     int 21h
     pop dx
 
     mov al,kbd
     dec al
 
     cmp al,kbd1 ;实长
     jnz INnib0
 
     xor bp,bp
     lea si,kbd2
 INnib1:  lodsb
 
     mov cx,16
     lea di,hextbl
     repne scasb
 
     jnz INnib0
     dec kbd1
 
     inc cx     ;转'[0-9a-f]'为0~15
     sub cx,16
     neg cx
 
     rept 4
     shl bx,1    ;bx接收nibble,左入0
     endm
 
     or bl,cl
 
     test kbd1,3   ;已收4个nibble
     jnz INnib1
 
     mov stk1[bp],bx
     add bp,TYPE stk1
 
     test kbd1,NIBSZ*2-1
     jnz INnib1
     ret
 INnib endp
 
 c ends
     end   @

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