162 lines
2.3 KiB
PHP
162 lines
2.3 KiB
PHP
;; File: floppy.inc
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;;
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;; Usefull links:
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;; - <https://wiki.osdev.org/Floppy_Disk_Controller>
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;; - <datasheet at http://www.osdever.net/documents/82077AA_FloppyControllerDatasheet.pdf>
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FLOPPY_BDEV_MAJOR = 0
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FLOPPY_CDEV_MAJOR = 9
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FLOPPY_NONE = 0x0
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FLOPPY_360KB = 0x1
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FLOPPY_1_2MB = 0x2
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FLOPPY_720KB = 0x3
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FLOPPY_1_44MB = 0x4
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FLOPPY_2_88MB = 0x5
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;; TODO: disk geometry for each floppy type
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HEADS_PER_CYLINDER = 2
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SECTORS_PER_CLUSTER = 1
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BYTES_PER_SECTOR = 512
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SECTORS_PER_TRACK = 18
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TOTAL_SECTORS = 2880
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FLOPPY_MAX = 2
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;; Struct: Floppy
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;;
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;; .active - XXX
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;; .motor - XXX
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struc Floppy {
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.active db ?
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.motor db ?
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}
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DEFN Floppy
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floppy_probe:
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mov al, CMOS_FLOPPY_TYPE
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out CMOS_COMMAND, al
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in al, CMOS_DATA
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mov ah, al
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and al, 0x0F
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and ah, 0xF0
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or al, al
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jz @f
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push ax
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mov esi, szMsgFloppy1Found
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call klog
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pop ax
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@@:
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or ah, ah
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jz @f
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mov esi, szMsgFloppy0Found
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call klog
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@@:
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ret
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floppy_init:
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call floppy_probe
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ret
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;; Function: floppy_lba_to_chs
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;; Convert LBA to CHS
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;;
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;; In:
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;; EAX - LBA
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;;
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;; Out:
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;; AL - Cylinder
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;; AH - Head
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;; CL - Sector
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floppy_lba_to_chs:
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push ebp
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mov ebp, esp
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sub esp, 1
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; CYL = LBA / (HPC * SPT)
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; HEAD = (LBA % (HPC * SPT)) / SPT
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; SECT = (LBA % (HPC * SPT)) % SPT + 1
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mov edx, eax
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shr edx, 16
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mov cx, (HEADS_PER_CYLINDER * SECTORS_PER_TRACK)
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div cx
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mov [ebp-1], al ; cyl
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mov ax, dx
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mov cl, SECTORS_PER_TRACK
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div cl
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mov cl, ah
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inc cl
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xchg al, ah
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mov al, [ebp-1]
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leave
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ret
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;; Function: floppy_strategy
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;; Do a read or write operation
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;;
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;; In:
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;; EAX - Address of <Buffer>
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floppy_strategy:
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ret
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;; Function: floppy_open
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;; Open the device for I/O operations
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floppy_open:
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push ebp
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mov ebp, esp
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mov eax, [ebp+4]
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cmp al, FLOPPY_MAX
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jb @f
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mov eax, ENXIO
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jmp .end
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@@:
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xor eax, eax
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.end:
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pop ebp
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ret
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;; Function: floppy_close
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;; Close a device.
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floppy_close:
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xor eax, eax
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ret
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floppy_ioctl:
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mov eax, ENODEV
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ret
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floppy_dump:
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ret
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floppy_psize:
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xor eax, eax
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ret
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floppy_irq:
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pusha
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mov esi, szMsgFloppyIRQ
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popa
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iret
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szMsgFloppyIRQ db 'Floppy: IRQ', 0
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floppy_device:
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db 'floppy', 0, 0
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dd floppy_init
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db FLOPPY_BDEV_MAJOR
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db FLOPPY_CDEV_MAJOR
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floppy_bdevsw:
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dd floppy_open
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dd floppy_strategy
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dd floppy_ioctl
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dd floppy_close
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dd floppy_dump
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dd floppy_psize
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szMsgFloppy0Found db "floppy: fd0 found", 0
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szMsgFloppy1Found db "floppy: fd1 found", 0
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