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;### fdc.inc ###  Menuetos floppy stuff.

;Version 0.2: Write individual tracks. / Sync ramdisk <-> floppy

;Version 0.1: Write full ramdisk to floppy.

;£loppyright Tolle.

;depends on:

;restorefatchain

;memmove

;Int 6 (sys32.inc) should call fdc_irq func.

;The ramdisk should be at 0x100000

;Keeping track of the tracks.

iglobal

  cylinder        db 0

  sector          db 1

  head            db 0

  ;Memory and dma variables.

  fdcmem          dd 0x100000

  cpymem          dd 0x100000

  dmamem          dd 0x100000

endg

uglobal

  dmasize         db 0x0

  dmamode         db 0x0

endg

iglobal

  ;function pointers.

  fdc_irq_func    dd fdc_null

  fdc_pump_func   dd fdc_null

endg

uglobal

  ;General stuff

  fdc_st0         db 0            ;status register 0 of last resultphase.

  fdc_mutex       db 0            ;wait in line. (Block calling app)

  fdc_callspending        db 0            ;mystery sauce

  fdc_settings    dd 0            ;bitfield.

endg

                                ;Bit 0  enable direct file write [yes/no]

fdc_set:                                ;ebx: fdc_settings bitfield.

mov [fdc_settings],ebx

ret

fdc_get:                                ;returns fdc_settings in ecx

mov ecx, [fdc_settings]

ret

fdc_init:                               ;start with clean tracks.

        mov edi,0xD201

        mov al,0

        mov ecx,160

        rep stosb

ret

fdc_filesave:                   ;ebx: cluster to be saved.

        pusha                   ;returns immediately. does not trigger a write.

        mov eax,ebx

        add eax,31

        mov bl,18

        div bl

        mov ah,0

        add eax,0xD201

        mov [eax],byte 1                ;This track is now dirty.

        popa

ret

fdc_writeramdisk:                       ;mark all tracks as dirty.

        mov edi,0xD201

        mov al,1

        mov ecx,160

        rep stosb

        jmp fdc_commitflush

fdc_commitfile:                 ;flush dirty tracks to floppy

        test [fdc_settings],1   ;...but only if this is really wanted by the user.

        je fdc_commitend

fdc_commitflush:

        cmp [fdc_callspending],5

        je fdc_commitend

        inc [fdc_callspending]

        cmp [fdc_callspending],1

        je fdc_commitonce

        fdc_commitend:

ret

fdc_commitonce:                 ;One at a time.

        .stall:

cli

        cmp [fdc_mutex],0

        jne .stallret

        mov [fdc_mutex],1

        jmp .goahead

        .stallret:

sti

        jmp .stall

        .goahead:

sti

fdc_commitramdisk:

        call restorefatchain

                                ;Move the bootsector to a safe place.

        mov eax,0x100000

        mov ebx,0xD000

        mov ecx,512

        call memmove

                                ;Always write the FAT table

        mov eax,0xD201

        mov [eax],byte 1

        inc eax

        mov [eax],byte 1

        mov [dmamode],0x4A      ;read from memory to floppy.

        mov [dmasize],0x1               ;read 512 bytes sectors.

        mov [fdc_irq_func],fdc_commitramdisk1

        call fdc_floppy_on              ;start floppy A: moter starts interruptflow.

        ret

fdc_commitramdisk1:

        mov [fdc_irq_func],fdc_recalibrate_result

        mov [fdc_pump_func],fdc_commitramdisk2

        call fdc_recalibrate            ;retract the head to cylinder 0, sector 1

        ret

fdc_commitramdisk2:

        mov[head],0             ;set variables.

        mov[cylinder],0

        mov [sector],1

        mov[cpymem],0x102400

        mov [fdc_pump_func],fdc_fullpump

        call fdc_write          ;fdc_write will continue interruptflow

ret

fdc_fullpump:

        add [dmamem],512

        add [sector],1

        cmp [sector],19

        jne .clusterwrite

        sub [dmamem],9216

        mov eax,[cpymem]

        mov ebx,[fdcmem]

        mov ecx,9216

        call memmove

        add [cpymem],9216

        cmp [head],0

        je .nocylinderchange

        add [cylinder],1

        .nocylinderchange:

        xor [head],1

        cmp [cylinder],80

        jne .noendofwrite

        mov[fdc_irq_func],fdc_complete

        call fdc_floppy_off

        call fdc_init

        jmp .end

        .noendofwrite:

        mov [sector],1

        .clusterwrite:

        xor eax,eax

        mov al,[cylinder]

        shl eax,1

        add al,[head]

        add eax,0xD201

        mov bl,[eax]

        cmp bl,1

        jne fdc_fullpump

        call fdc_write

        .end:

ret

fdc_write:

        call fdc_program_dma

        call fdc_seek

ret

fdc_seek:

        mov al, 0x0f

        call fdc_write_reg

        mov al,[head]

        shl al,2

        call fdc_write_reg

        mov al,[cylinder]

        call fdc_write_reg

        mov [fdc_irq_func],fdc_seek_result

ret

fdc_seek_result:

        call fdc_sensei

        cmp al,[cylinder]

        je .succes

        call fdc_seek

        jmp .end

        .succes:

        call fdc_write_sector

        .end:

ret

fdc_write_sector:

        mov al,0x45             ;write sector command

fdc_commandphase:

        call fdc_write_reg

        mov al,[head]

        shl al,2

        call fdc_write_reg

        mov al,[cylinder]

        call fdc_write_reg

        mov al,[head]

        call fdc_write_reg

        mov al,[sector]

        call fdc_write_reg

        mov al,2                        ;Sector size (2 ~> 512 bytes)

        call fdc_write_reg

        mov al,18                       ;last sector on track.

        call fdc_write_reg

        mov al,27                       ;length of GAP3

        call fdc_write_reg

        mov al,0xFF             ;data length, ignored.

        call fdc_write_reg

        mov [fdc_irq_func],fdc_resultphase

ret

fdc_resultphase:

        call fdc_read_reg

        mov [fdc_st0],al

        mov cx,6

        .readresult:

        call fdc_read_reg

        loop .readresult

        and [fdc_st0],11000000b

        cmp [fdc_st0],byte 0

        jz .succes

        call fdc_seek

        jmp .end

        .succes:

        call [fdc_pump_func]

        .end:

ret

fdc_sensei:

        mov al,0x08             ;get interrupt status command

        call fdc_write_reg

        call fdc_read_reg               ;get result in al;

        and al,0x80

        cmp al,0x80

        je fdc_sensei           ;retry

        call fdc_read_reg

ret

fdc_program_dma:

        mov al,0

        out 0x0c,al     ; reset the flip-flop to a known state.

        mov al,6                ; mask channel 2 so we can reprogram it.

        out 0x0a,al

        mov al,[dmamode]        ; 0x46 -> Read from floppy - 0x4A Write to floppy

        out 0x0b,al

        mov al,0

        out 0x0c,al     ; reset the flip-flop to a known state.

        mov eax,[dmamem]

        out 0x04,al     ; set the channel 2 starting address to 0

        shr eax,8

        out 0x04,al

        shr eax,8

        out 0x81,al

        mov al,0

        out 0x0c, al    ; reset flip-flop

        mov al, 0xff    ;set count (actual size -1)

        out 0x5, al

        mov al, [dmasize]       ;(0x1ff = 511 / 0x23ff =9215)

        out 0x5,al

        mov al,2

        out 0xa,al

ret

fdc_recalibrate:

        mov al,0x07             ;calibrate command

        call fdc_write_reg

        mov al,0                        ;select drive 0

        call fdc_write_reg

ret

fdc_recalibrate_result:

        mov al,0x08             ;get interrupt status command

        call fdc_write_reg              ;send it

        call fdc_read_reg               ;get command in al;

        cmp al,0x80

        je fdc_recalibrate_result

        mov ah,al

        call fdc_read_reg

        cmp ah,0x70

        jne .end

        call fdc_recalibrate

        jmp .reallyend

        .end:

        call [fdc_pump_func]

        .reallyend:

ret

fdc_busy:

        .command_check:

        mov dx,0x3F4

        in al,dx

        and al,0x10

        cmp al,0x10

        je .command_check

ret

fdc_read_reg:

        status_check:

        mov dx,0x3F4

        in al,dx

        and al,0xc0

        cmp al,0xc0

        jne status_check

        mov dx, 0x3F5

        in al, dx

ret

fdc_write_reg:

        mov bl,al

        .command_check:

        mov dx,0x3F4

        in al,dx

        and al,0x80

        cmp al,0x80

        jne .command_check

        mov al,bl

        mov dx,0x3F5

        out dx,al

ret

fdc_floppy_off:

        mov al,0xC

        mov dx,0x3f2

        out dx,al

ret

fdc_floppy_on:

        mov  dx,0x3f2

        mov  al,0x0

        out  dx,al

        mov  al,0x1C

        out  dx,al

        mov  eax,50

        call delay_hs

ret

fdc_complete:

        mov eax,0xD000

        mov ebx,0x100000

        mov ecx,512

        call memmove

        mov [fdc_irq_func],fdc_null

        mov [fdc_mutex],0

        dec [fdc_callspending]

        cmp [fdc_callspending],0

        je  .realyend

        mov [fdc_mutex],1

        call fdc_commitramdisk

        .realyend:

ret

fdc_irq:

        call [fdc_irq_func]

fdc_null:

ret