Nineth Day, continue to read and write floppy disk

Today, the code is written to read and write floppy disk, the goal is to cross-track read and write operations into a number of single-track read and write operations. The idea is this: the first sector is located in the track of the sector read and write, and then modify the output parameters--Remove the part that has been read and write, recalculate the starting logical sector area code, the number of sectors to read and write, the memory buffer address, so that you can read and write as a new task. In order to facilitate the test, put yesterday's code together with the output text part to paste up:

;  readwritefloppylogicalsectors.nas; =============================================================== =========================[section .data]    icylinder dd 0     ihead     dd 0    isector   dd  0    nSectorsOfThisTrack dd  0   ;  Number of sectors to read and write in the track where the starting sector is located     nSectorsOfOpetate   dd  0   ;   Number of sectors actually successfully read and written     strFormat db  '  ibeginlogicalsector = %04d,  nsectors = %02d, memory address = %04d ,clylinder = %02d,  head = %02d, sector = %02d ',  0xa, 0; *************************** ;  =========================================== =============================================[section .text]extern _printfglobal _readwritefloppylogicalsectors; -------------- --------------------------------------------------------------------------;  function Format: int operateonetrack (int ifunctionnumber,;                        int iBeginLogicalSector, int  Nsectors, unsigned char *puchbuffer);;   function: Read/write floppy logical Sector;  entry parameter:ifunctionnumber =   function number:02h  read, 03h  write;            iBeginLogicalSecot =  Start logical sector area code;            nSectors =  number of sectors to read (all sectors that need to read and write must be within the same track);            puchBuffer =  memory buffer address for storing data;  return value: 0  =  success, other values  =  error status code _OPERATEONETRACK:&NBSP;&NBSP;&NBSP;&NBSP;PUSH&NBSP;EBP    mov ebp, esp    sub esp, 7 * 4     ;  Calculate cylinder number:=  logical sector area code  div  (number of heads  *  number of sectors per track)      xor edx, edx    mov eax, [ebp + 3 * 4]     mov ebx, 36    div ebx    mov [ icylinder], eax    ;  Calculate Magnetic number:=  (logical sector area code  div  number of sectors per track)  mod  head count     xor edx, edx    mov eax, [ebp + 3  * 4]    mov ebx, 18    div ebx     xor edx, edx                     ;  only a reserved quotient, discard the remainder     mov ebx, 2     div ebx    mov [ihead], edx    ;  Calculate sector Area code:=  (logical Sector Code  mod  number of sectors per track)  + 1    xor edx, edx    mov  eax, [ebp + 3 * 4]    mov ebx, 18     div ebx    inc edx    mov [iSector],  edx    ;  output calculation Results--The actual application must be swapped with the call  int 0x13  code     mov  eax, [isector]    push eax    mov eax, [ ihead]    push eax    mov eax, [icylinder]     push eax    mov eax, [ebp + 5 * 4]  &NBSP;&NBSP;&NBSP;PUSH&NBSP;EAX&NBSP;&NBSP;&NBSP;&NBSP;MOV&NBSP;EAX,&NBSP;[EBP&NBSP;+&NBSP;4&NBSP;*&NBSP;4]     push  Eax    mov eax, [ebp + 3 * 4]    push  eax    mov eax, strFormat    push eax     call _printf    add esp, 7 * 4     ;  return value     mov bl, ah    xor eax, eax     mov al, bl    leave    ret; --- -------------------------------------------------------------------------------------;  function Format:int  Operatefloppylogicalsectors (int ifunctionnumber,;                        int  Ibeginlogicalsector, int nsectors, unsigned char *puchbuffer);;   function: Read/write floppy logical Sector;  entry parameter:ifunctionnumber =  function number:02h  read, 03h  write;            ibeginlogicalsecot  =  Start logical sector area code;           nsectors =  Number of sectors to read and write;           puchbuffer =  the memory buffer address where the data is stored ;  return value:eax =  The number of sectors that were actually successfully read and written _READWRITEFLOPPYLOGICALSECTORS:&NBSP;&NBSP;&NBSP;&NBSP;PUSH&NBSP;EBP     mov ebp, esp    sub esp, 4 * 4     ;  Check the validity of the parameters label_checkparameter:    mov eax, [ebp +  2 * 4]          ; 2 =<  function No.  =< 3    cmp eax, 2    jl label_return     cmp eax, 3    jg Label_Return     mov eax, [ebp + 3 * 4]          ; 0 =<   Starting logical Sector code  =< 2879    cmp eax, 0    jl  label_return    cmp eax, 2879    jg label_return     mov ebx, [ebp + 4 * 4]           ; 1 =<  number of sectors to read and write  =< 2880    cmp  ebx, 1    jl label_return    cmp ebx, 2880     jg Label_Return    add ebx, eax                     ;  Starting logical sector area code  +  number of sectors to read and write  =< 2880    cmp ebx, 2880     jg label_return    mov ebx, [ebp + 5 * 4]           ;  Memory buffer Address &NBSP;!=&NBSP;NULL&NBSP;&NBSP;&NBSP;&NBSP;CMP&NBSP;EBX,  0    je Label_Return    ;  calculates the number of read/write sectors in the track where the starting sector is located      xor edx, edx    mov ebx, 18                      ; s  =  ( LBA mod NS )  + 1    div ebx                           ;  starting logical Sector area code  /  number of sectors per track                                       ;    remainder  =  starting logical sector in the sector area where the track is located  - 1     sub ebx, edx                     ;  number of sectors per track  -(sector area code  - 1) =                                      ;    The number of sectors (including that sector) in the track in which the starting logical sector is located, followed by that sector                                       ;    the number of read/write sectors in the track where the starting sector is located     ;  The number of remaining read-write sectors compared to the number of sectors to be read     mov ecx, [ebp + 4 * 4]     cmp ebx, ecx    jl label_less_1    mov [nsectorsofthistrack], ecx   ;    is greater than the number of sectors to read only read and write     jmp label_call_operateonetracklabel_less_1:     mov [nSectorsOfThisTrack], ebx  ;    less than read and write all the remainder of the track     ;  Read and write the sectors on which the starting sector is located to read and write label_call_operateonetrack:    mov  Eax, [ebp + 5 * 4]    push eax    mov  eax, [nsectorsofthistrack]    push eax    mov eax , [ebp + 3 * 4]    push eax    mov  Eax, [ebp + 2 * 4]    push eax    call  _OPerateOneTrack    add esp, 4 * 4    ;  operateonetrack  The return value is non- 0, indicating a read-write error     cmp eax, 0    jne label_return     ;  cumulative number of sectors successfully read/write     mov eax, [nsectorsofthistrack]     add [nSectorsOfOpetate], eax    ;  adjust each parameter value      add [ebp + 3 * 4], eax           ;  adjust the starting logical sector area code &NBSP;&NBSP;&NBSP;&NBSP;SUB&NBSP;[EBP&NBSP;+&NBSP;4&NBSP;*&NBSP;4],  eax          ;  adjust the number of sectors to read and write      Mov ebx, 512    mul ebx    add [ebp + 5  * 4], eax          ;  Adjust memory buffer address      ;  Loop Continue reading     jmp Label_CheckParameterLabel_Return:     mov eax, [nsectorsofopetate]    leave    ret; ***************************** ***********************************************************

    Make a test with the C language call:

/* test.c */#include  <stdio.h> #include  <stdlib.h>extern int  Readwritefloppylogicalsectors (int ifunctionnumber,                        int  Ibeginlogicalsector, int nsectors, unsigned char *puchbuffer); Int main (int  Argc, int argv[]) {    int ifunctionnumber = 2,  ibeginlogicalsector = 3,  nsectors = 35, nret = 0;     unsigned char *puchBuffer;    puchBuffer =  (unsigned  char *) malloc (512 * nsectors);     if (puchbuffer == null)      {        puts ("  request memory failure \ n");         return -1;    }    printf ("  data from the logical sector  %04d %s %04d  sector of a floppy disk to memory  % d  Place \         ibeginlogicalsector, ifunctionnumber ==  2 ?  "read"  :  "write",  nsectors, puchbuffer);     nret =  readwritefloppylogicalsectors (Ifunctionnumber, ibeginlogicalsector, nsectors, puchbuffer) ;     free (Puchbuffer);     printf ("  actual number of Read sectors:  %d\n",  nRet );     return nret == 0 ? -1 : 0;}

#MAkeFileALL: nasm-felf readwritefloppylogicalsectors.nasgcc-o Test test.c ReadWriteFloppyLogicalSectors.oCLS:del *. o *.exe

The output seems to be right:

Data from the logical sector of the floppy disk 3 read 35 sectors stored to memory 4007112

Ibeginlogicalsector = 0003, nsectors =, Memory Address = 4007112, Clylinder = xx, Head = xx, Sector = 04

Ibeginlogicalsector = 0018, nsectors =, Memory Address = 4014792, Clylinder = xx, Head =, Sector = 01

Ibeginlogicalsector = 0036, nsectors = Clylinder, Memory Address = 4024008, Sector =----

Number of actual read sectors: 35

Nineth Day, continue to read and write floppy disk