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bd_callbacks:

        dd      bd_callbacks.end - bd_callbacks         ; strucsize

        dd      0       ; no close function

        dd      0       ; no closemedia function

        dd      bd_querymedia

        dd      bd_read_interface

        dd      bd_write_interface

        dd      0       ; no flush function

        dd      0       ; use default cache size

.end:

proc bd_read_interface stdcall uses edi, \

        userdata, buffer, startsector:qword, numsectors

        ; userdata = old [hdpos] = 80h + index in NumBiosDisks

        ; buffer = pointer to buffer for data

        ; startsector = 64-bit start sector

        ; numsectors = pointer to number of sectors on input,

        ;  must be filled with number of sectors really read

locals

sectors_todo    dd      ?

endl

; 1. Initialize number of sectors: get number of requested sectors

; and say that no sectors were read yet.

        mov     ecx, [numsectors]

        mov     eax, [ecx]

        mov     dword [ecx], 0

        mov     [sectors_todo], eax

; 2. Acquire the global lock.

        mov     ecx, ide_mutex

        call    mutex_lock

; 3. Convert parameters to the form suitable for worker procedures.

; Underlying procedures do not know about 64-bit sectors.

; Worker procedures use global variables and edi for [buffer].

        cmp     dword [startsector+4], 0

        jnz     .fail

        and     [hd_error], 0

        mov     eax, [userdata]

        mov     [hdpos], eax

        mov     eax, dword [startsector]

        mov     edi, [buffer]

; 4. Worker procedures take one sectors per time, so loop over all sectors to read.

.sectors_loop:

        call    bd_read

        cmp     [hd_error], 0

        jnz     .fail

        mov     ecx, [numsectors]

        inc     dword [ecx]     ; one more sector is read

        dec     [sectors_todo]

        jz      .done

        inc     eax

        jnz     .sectors_loop

; 5. Loop is done, either due to error or because everything is done.

; Release the global lock and return the corresponding status.

.fail:

        mov     ecx, ide_mutex

        call    mutex_unlock

        or      eax, -1

        ret

.done:

        mov     ecx, ide_mutex

        call    mutex_unlock

        xor     eax, eax

        ret

endp

proc bd_write_interface stdcall uses esi edi, \

        userdata, buffer, startsector:qword, numsectors

        ; userdata = old [hdpos] = 80h + index in NumBiosDisks

        ; buffer = pointer to buffer with data

        ; startsector = 64-bit start sector

        ; numsectors = pointer to number of sectors on input,

        ;  must be filled with number of sectors really written

locals

sectors_todo    dd      ?

endl

; 1. Initialize number of sectors: get number of requested sectors

; and say that no sectors were read yet.      

        mov     ecx, [numsectors]

        mov     eax, [ecx]

        mov     dword [ecx], 0

        mov     [sectors_todo], eax

; 2. Acquire the global lock.

        mov     ecx, ide_mutex

        call    mutex_lock

; 3. Convert parameters to the form suitable for worker procedures.

; Underlying procedures do not know about 64-bit sectors.

; Worker procedures use global variables and esi for [buffer].

        cmp     dword [startsector+4], 0

        jnz     .fail

        and     [hd_error], 0

        mov     eax, [userdata]

        mov     [hdpos], eax

        mov     esi, [buffer]

        lea     edi, [startsector]

        mov     [cache_chain_ptr], edi

; 4. Worker procedures take max 16 sectors per time,

; loop until all sectors will be processed.

.sectors_loop:

        mov     ecx, 16

        cmp     ecx, [sectors_todo]

        jbe     @f

        mov     ecx, [sectors_todo]

@@:

        mov     [cache_chain_size], cl

        call    bd_write_cache_chain

        cmp     [hd_error], 0

        jnz     .fail

        movzx   ecx, [cache_chain_size]

        mov     eax, [numsectors]

        add     [eax], ecx

        sub     [sectors_todo], ecx

        jz      .done

        add     [edi], ecx

        jc      .fail

        shl     ecx, 9

        add     esi, ecx

        jmp     .sectors_loop

; 5. Loop is done, either due to error or because everything is done.

; Release the global lock and return the corresponding status.

.fail:

        mov     ecx, ide_mutex

        call    mutex_unlock

        or      eax, -1

        ret

.done:

        mov     ecx, ide_mutex

        call    mutex_unlock

        xor     eax, eax

        ret

endp

; This is a stub.

proc bd_querymedia stdcall, hd_data, mediainfo

        mov     eax, [mediainfo]

        mov     [eax+DISKMEDIAINFO.Flags], 0

        mov     [eax+DISKMEDIAINFO.SectorSize], 512

        or      dword [eax+DISKMEDIAINFO.Capacity], 0xFFFFFFFF

        or      dword [eax+DISKMEDIAINFO.Capacity+4], 0xFFFFFFFF

        xor     eax, eax

        ret

endp

; \begin{diamond}

uglobal

bios_hdpos      dd 0       ; 0 is invalid value for [hdpos]

bios_cur_sector dd ?

bios_read_len   dd ?

endg

;-----------------------------------------------------------------------------

align 4

bd_read:

        push    eax

        push    edx

        mov     edx, [bios_hdpos]

        cmp     edx, [hdpos]

        jne     .notread

        mov     edx, [bios_cur_sector]

        cmp     eax, edx

        jb      .notread

        add     edx, [bios_read_len]

        dec     edx

        cmp     eax, edx

        ja      .notread

        sub     eax, [bios_cur_sector]

        shl     eax, 9

        add     eax, (OS_BASE+0x9A000)

        push    ecx esi

        mov     esi, eax

        mov     ecx, 512/4

        cld

        rep movsd

        pop     esi ecx

        pop     edx

        pop     eax

        ret

.notread:

        push    ecx

        mov     dl, 42h

        mov     ecx, 16

        call    int13_call

        pop     ecx

        test    eax, eax

        jnz     .v86err

        test    edx, edx

        jz      .readerr

        mov     [bios_read_len], edx

        mov     edx, [hdpos]

        mov     [bios_hdpos], edx

        pop     edx

        pop     eax

        mov     [bios_cur_sector], eax

        jmp     bd_read

.readerr:

.v86err:

        mov     [hd_error], 1

        jmp     hd_read_error

;-----------------------------------------------------------------------------

align 4

bd_write_cache_chain:

        pusha

        mov     edi, OS_BASE + 0x9A000

        movzx   ecx, [cache_chain_size]

        push    ecx

        shl     ecx, 9-2

        rep movsd

        pop     ecx

        mov     dl, 43h

        mov     eax, [cache_chain_ptr]

        mov     eax, [eax]

        call    int13_call

        test    eax, eax

        jnz     .v86err

        cmp     edx, ecx

        jnz     .writeerr

        popa

        ret

.v86err:

.writeerr:

        popa

        mov     [hd_error], 1

        jmp     hd_write_error

;-----------------------------------------------------------------------------

uglobal

int13_regs_in   rb sizeof.v86_regs

int13_regs_out  rb sizeof.v86_regs

endg

;-----------------------------------------------------------------------------

align 4

int13_call:

; Because this code uses fixed addresses,

; it can not be run simultaniously by many threads.

; In current implementation it is protected by common mutex 'ide_status'

        mov     word [OS_BASE + 510h], 10h             ; packet length

        mov     word [OS_BASE + 512h], cx              ; number of sectors

        mov     dword [OS_BASE + 514h], 9A000000h      ; buffer 9A00:0000

        mov     dword [OS_BASE + 518h], eax

        and     dword [OS_BASE + 51Ch], 0

        push    ebx ecx esi edi

        mov     ebx, int13_regs_in

        mov     edi, ebx

        mov     ecx, sizeof.v86_regs/4

        xor     eax, eax

        rep stosd

        mov     byte [ebx+v86_regs.eax+1], dl

        mov     eax, [hdpos]

        lea     eax, [BiosDisksData+(eax-80h)*4]

        mov     dl, [eax]

        mov     byte [ebx+v86_regs.edx], dl

        movzx   edx, byte [eax+1]

;        mov     dl, 5

        test    edx, edx

        jnz     .hasirq

        dec     edx

        jmp     @f

.hasirq:

        pushad

        stdcall enable_irq, edx

        popad

@@:

        mov     word [ebx+v86_regs.esi], 510h

        mov     word [ebx+v86_regs.ss], 9000h

        mov     word [ebx+v86_regs.esp], 0A000h

        mov     word [ebx+v86_regs.eip], 500h

        mov     [ebx+v86_regs.eflags], 20200h

        mov     esi, [sys_v86_machine]

        mov     ecx, 0x502

        push    fs

        call    v86_start

        pop     fs

        and     [bios_hdpos], 0

        pop     edi esi ecx ebx

        movzx   edx, byte [OS_BASE + 512h]

        test    byte [int13_regs_out+v86_regs.eflags], 1

        jnz     @f

        mov     edx, ecx

@@:

        ret

; \end{diamond}