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171 líneas
4.9 KiB
171 líneas
4.9 KiB
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; This is the "program" to execute a program
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xex:
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pusha ; save state before program
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sub sp, 512
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mov [.program_executable_buffer], sp
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;mov [.program_executable_buffer], sp
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call os_clear_screen
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call lsfs_list_files_command
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; move cursor to the bootom
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xor ax, ax
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xor bx, bx
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mov ah, 0x02
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mov bh, 0x00 ; page number 0
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mov dh, 0x17 ; row zero
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mov dl, 0x00 ; coloumn zero
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int 0x10
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mov si, .welcome_xex_enter_fileindex
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call print
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; Ask the user for the filename
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xor bx, bx
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xor cx, cx ; are going to be the counter
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xor dx, dx
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.enter_fileindex_loop:
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push cx
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.loop_no_push:
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mov ax, 0x10 ; BIOS call to wait for key
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int 0x16
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cmp ax, 0x1c0d ; enter key
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je .fileindex_done
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cmp ax, 0x0e08 ; backspace
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jne .no_enter_fileindex
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cmp cx, 0
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je .loop_no_push
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pop cx
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sub cx, 1
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mov bx, [.program_executable_buffer]
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add bx, cx
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mov BYTE [bx], 0
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; Go back one space
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mov ax, 0x0e08 ; ah=0x0e means teletype output. al=0x08 means backspace character.
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int 0x10
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; Place a NULL
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mov al, 0x0 ; NULL
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int 0x10
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; Go back one space again as the above print of NULL pushes the cursor forward again.
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mov ax, 0x0e08
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int 0x10
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jmp .enter_fileindex_loop
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.no_enter_fileindex:
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mov bh, 0x00
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mov bl, 0x02
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mov ah, 0x0E
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int 0x10 ; print char
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pop cx
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mov bx, [.program_executable_buffer]
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add bx, cx
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mov [bx], al
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add cx, 1
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; fileindex must only be 120 chars
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cmp cx, 120
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jae .fileindex_done
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jmp .enter_fileindex_loop
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.fileindex_done:
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pop cx ; Cleanup, and now contain filename size
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mov ax, cx
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add ax, [.program_executable_buffer]
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mov bx, ax
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mov BYTE [bx], 0
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mov si, [.program_executable_buffer]
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call zstring_to_integer ; ax now contain the interger index for the file
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mov [.fileindex_for_open_file], ax ; save the file index
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mov ax, [.fileindex_for_open_file]
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mov bx, [.program_executable_buffer]
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.xex_lsfs_read_file:
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; INPUT ax = file index
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; INPUT bx = filebuffer
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pusha ; save all register state
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; We need to find the data pointers for the file.
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push bx
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mov dx, 24 ; LSFS_magic_start_sector
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add ax, dx ; senctor number, into the master Table.
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mov WORD [XEXPACK.db_addr_offset], xex_lsfs_loading_buffer
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mov WORD [XEXPACK.lba_addr_dw_low], ax
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mov WORD [XEXPACK.blkcnt], 0x1 ; Read to sectors, that is what the space is for the buffer in svim
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mov WORD [XEXPACK.db_addr_segment], 0x50
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mov si, XEXPACK ; address of "disk address packet"
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mov ah, 0x42 ; READ
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mov dl, [global_disk_identifier]
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int 0x13
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pop bx
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; Save the buffer addr
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mov bx, [xex_lsfs_loading_buffer + 288] ; this is the first data pointer
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mov ax, bx
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mov WORD [XEXPACK.lba_addr_dw_low], bx
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mov WORD [XEXPACK.blkcnt], 0x4 ; Read to sectors, that is what the space is for the buffer in svim
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mov WORD [XEXPACK.db_addr_segment], 0x2000
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mov WORD [XEXPACK.db_addr_offset], 0x0
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mov si, XEXPACK ; address of "disk address packet"
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mov ah, 0x42 ; READ
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mov dl, [global_disk_identifier]
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int 0x13
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popa
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mov ax, [xex_lsfs_loading_buffer + 264]
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; I guess we should have something like
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push cs ; this gives us the correct code segment for the kernel
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push .this_place ; this gives the correct adress to come back from the program.
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push 0x2000
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push 0x0
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;push 0x0050
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;push 0x0512
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mov ax, 0x2000
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mov ds, ax ; move data segment to the program start
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retf
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.this_place:
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push ax
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mov ax, 0x50
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mov ds, ax ; Back to the kernel space
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call printCRLF
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mov si, .program_output_text
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call print
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pop ax
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call dumpax
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;mov bx, ss
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;call bx:ax ; here. We want to execute the file that we just have benn loaded in memory
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; The executable should make use of the global systemcall table.
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; That is what we are trying to get to work here.
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add sp, 512
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popa ; retore
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ret
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.welcome_xex_enter_fileindex db 'Enter program index to execute: ', 0
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.program_output_text db 'Program has terminated with return value: ', 0
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.fileindex_for_open_file dw 0
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.program_executable_buffer dw 0
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align 2
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xex_lsfs_loading_buffer times 512 db 0
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XEXPACK:
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.dap_Size: db 0x10 ; This is always 16 bytes (0x10)
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.rev_byte: db 0x0 ; reserved byte, should always be zero
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.blkcnt: dw 0x0 ; int 13 resets this to # of blocks actually read/written
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.db_addr_offset: dw 0x0 ; memory buffer destination address (0:7c00)
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.db_addr_segment: dw 0x0 ; in memory page zero
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.lba_addr_dw_low: dd 0x0 ; put the lba to read in this spot
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.lba_addr_dw_high: dd 0x0 ; more storage bytes only for big lba's ( > 4 bytes )
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