Compare commits
2 Commits
| Author | SHA1 | Date |
|---|---|---|
Juhani Krekelä
|
3f4c6c0559 | |
|
Juhani Krekelä
|
7e41612687 |
|
|
@ -1,4 +1,3 @@
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*.bin
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*.img
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*.d
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*.krn
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|
|
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16
Makefile
16
Makefile
|
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@ -1,30 +1,24 @@
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FLOPPY = 360
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FLOPPY = 1440
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.SUFFIXES:
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.SUFFIXES: .bin .asm
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all: nor86.img
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nor86.img: boot.bin nor86.krn CC0 README.md
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nor86.img: bootsect.bin kernel.bin CC0 README.md
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rm -f $@
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mkdosfs -C $@ $(FLOPPY)
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rw -i boot.bin -o $@
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rw -i bootsect.bin -o $@
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mcopy -i $@ CC0 ::
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mcopy -i $@ README.md ::
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mcopy -i $@ *.asm ::
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mcopy -i $@ *.inc ::
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mcopy -i $@ nor86.krn ::
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nor86.krn: kernel.asm
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nasm -fbin -d F$(FLOPPY) -o $@ $<
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nasm -MD $@.d -d F$(FLOPPY) -fbin -o $@ $<
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mcopy -i $@ kernel.bin ::
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.asm.bin:
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nasm -fbin -d F$(FLOPPY) -o $@ $<
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nasm -MD $@.d -d F$(FLOPPY) -fbin -o $@ $<
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clean:
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rm -f *.bin *.img *.bin.d *.krn *.krn.d
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rm -f *.bin *.img *.bin.d
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run: nor86.img
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qemu-system-i386 -fda $<
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|
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@ -8,6 +8,6 @@ Floppy sizes
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------------
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You can build either a 1440K or a 360K floppy image from Nor86 sources, the
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default being 360K. To build a 1440K floppy instead, run:
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default being 1440K. To build a 360K floppy instead, run:
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make FLOPPY=1440
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make FLOPPY=360
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|
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@ -67,6 +67,29 @@ _start:
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; Save bootdrive
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mov [drivenumber], dl
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select_os:
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mov si, prompt
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.print:
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lodsb
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test al, al
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jz .end
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; On the original IBM PC BIOS the int 0x10 will clobber this
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mov ah, 0xe
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int 0x10
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jmp .print
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.end:
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xor ax, ax
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int 0x16
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cmp al, 'e'
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jne calc_constants
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mov si, ettinos_kernel_name
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mov di, kernel_name
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mov cx, 11
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rep movsb
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calc_constants:
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; Disk organization:
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; Reserved sectors (MBR)
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@ -97,15 +120,25 @@ calc_constants:
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fat:
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; FAT1 (the main one) follows right after bootsector(s)
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mov ax, [reservedsectors]
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call chs
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; TODO: handle possible crossing of track boundary
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mov ax, [sectorsperfat]
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mov ah, 2
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mov dl, [drivenumber]
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mov bx, 0x8000
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mov cx, [sectorsperfat]
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call loadsectors
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int 0x13
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root_dir:
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mov ax, [rootdir]
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call chs
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; TODO: handle possible crossing of track boundary
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mov ax, [rootdirsectors]
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mov ah, 2
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mov dl, [drivenumber]
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mov bx, 0x500
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mov cx, [rootdirsectors]
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call loadsectors
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int 0x13
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search_root:
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mov bx, [rootdirentries]
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@ -120,53 +153,26 @@ search_root:
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cmp byte [si], 0
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je .end
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; Deleted file?
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cmp byte [si], 0xe5
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je .skipentry
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test byte [si + 11], 0x08 + 0x10
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jnz .skipentry
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jz .isfile
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; Make sure the file has non-zero size
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; File size must be <32K anyways so don't bother with >64K
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cmp word [si + 28], 0
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jne .isfile
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.skipentry:
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add si, 32
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jmp .entry
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.isfile:
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.nor86:
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cmp word [si + 8], 'KR'
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jne .ettinos
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cmp byte [si + 10], 'N'
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jne .ettinos
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mov cx, 11
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mov bx, kernel_name
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mov ax, [si + 26] ; First cluster
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mov [kernel_cluster], ax
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.compare:
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lodsb
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cmp al, [bx]
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jne .nomatch
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inc bx
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loop .compare
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jmp .skipentry
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jmp found
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.ettinos:
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mov cx, 11
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mov bx, ettinos_kernel_name
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.compare:
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lodsb
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cmp al, [bx]
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jne .nextentry
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inc bx
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loop .compare
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; SI points to 11 bytes after the start of the
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; entry, so adjust offset
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mov ax, [si - 11 + 26] ; First cluster
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mov [ettinos_kernel_cluster], ax
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inc cx ; Offset so that falling through will work
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.nextentry:
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.nomatch:
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; Each entry is 32 bytes long
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; During each iteration of the compare loop, si is
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; incremented and cx is decremented
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@ -180,47 +186,20 @@ search_root:
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.end:
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which_found:
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mov bx, [kernel_cluster]
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mov cx, [ettinos_kernel_cluster]
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test bx, bx
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jz .no_nor86
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test cx, cx
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jz found
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mov si, choose_msg
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.loop:
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lodsb
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test al, al
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jz .end
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mov ah, 0xe
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int 0x10
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jmp .loop
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.end:
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xor ax, ax
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int 0x16
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cmp ah, 0x12 ; E-key
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je found_cx
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jmp found
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.no_nor86:
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test cx, cx
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jnz found_cx
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notfound:
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mov si, notfound_msg
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jmp fatal_error
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; TODO: Better error messages
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mov ax, 0x0e00 + '?'
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int 0x10
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found_cx:
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mov bx, cx
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hang:
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hlt
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jmp hang
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found:
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mov ax, bx
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; SI points to 11 bytes after the start of the entry, so adjust all
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; offsets
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; TODO: Handle zero-length files
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mov ax, [si - 11 + 26] ; First cluster
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push ax
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; Load OS at the start of the memory
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@ -231,8 +210,7 @@ found:
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.tosector:
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; Adjust the cluster number to account for first two
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; "clusters" in the FAT being used for metadata
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dec ax
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dec ax
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sub ax, 2
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; Scale by number of sectors per cluster
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xor bx, bx
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@ -243,12 +221,27 @@ found:
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add ax, [rootdir]
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add ax, [rootdirsectors]
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.load:
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; Load sectors
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pop bx
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xor cx, cx
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mov cl, [sectorspercluster]
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call loadsectors
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; Load sectors
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pop bx
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xor cx, cx
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mov cl, [sectorspercluster]
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mov dl, [drivenumber]
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.loop:
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push ax
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push cx
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call chs
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mov ah, 2
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mov al, 1
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int 0x13
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pop cx
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pop ax
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add bx, 512
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inc ax
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loop .loop
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.next:
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pop ax
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@ -271,7 +264,11 @@ found:
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; ^ where we start reading on odd cluster numbers
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; ^^^^^ loading word: 0xXYZA
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test ax, 1
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jz .even
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jnz .odd
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.even:
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and dx, 0x0fff
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jmp .check_cluster
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.odd:
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shr dx, 1
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@ -279,9 +276,6 @@ found:
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shr dx, 1
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shr dx, 1
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.even:
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and dx, 0x0fff
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.check_cluster:
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mov ax, dx
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@ -297,102 +291,51 @@ execute_kernel:
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mov dl, [drivenumber]
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jmp 0:0x500
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; Note: bx will point to after the read data
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; Note: ax, cx, dx, and di will be clobbered
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loadsectors:
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chs:
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push ax
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push bx
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.loop:
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mov di, 3 + 1 ; Retry thrice, + 1 is since we dec first
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; Save drive number
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mov bl, dl
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.retry:
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xor dx, dx
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; cylinder (track) - head - sector
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; cylinder = LBA / sectorspertrack / heads
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; head = LBA / sectorspertrack % heads
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; sector = LBA % sectorspertrack + 1
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div word [sectorspertrack]
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; ax = LBA / sectorspertrack
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; dx = LBA % sectorspertrack
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push ax
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push cx
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; sector
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mov cl, dl
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inc cl
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.chs:
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xor dx, dx
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; cylinder (track) - head - sector
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; cylinder = LBA / sectorspertrack / heads
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; head = LBA / sectorspertrack % heads
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; sector = LBA % sectorspertrack + 1
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div word [sectorspertrack]
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; ax = LBA / sectorspertrack
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; dx = LBA % sectorspertrack
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xor dx, dx
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div word [heads]
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; ax = LBA / sectorspertrack / heads
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; dx = LBA / sectorspertrack % heads
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|
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; sector
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mov cl, dl
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inc cl
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; head
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mov dh, dl
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|
||||
xor dx, dx
|
||||
div word [heads]
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; ax = LBA / sectorspertrack / heads
|
||||
; dx = LBA / sectorspertrack % heads
|
||||
; cylinder (track)
|
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mov ch, al
|
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;shr ax, 1
|
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;shr ax, 1
|
||||
;and al, 0xC0
|
||||
;or cl, al
|
||||
|
||||
; head
|
||||
mov dh, dl
|
||||
|
||||
; cylinder (track)
|
||||
mov ch, al
|
||||
;shr ax, 1
|
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;shr ax, 1
|
||||
;and al, 0xC0
|
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;or cl, al
|
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|
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mov ax, 0x0201
|
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mov dl, [drivenumber]
|
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int 0x13
|
||||
|
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jc .error
|
||||
|
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mov ax, 0x0e00 + '.'
|
||||
int 0x10
|
||||
|
||||
pop cx
|
||||
pop ax
|
||||
|
||||
inc ax
|
||||
add bx, 512
|
||||
|
||||
loop .loop
|
||||
; Restore drive number
|
||||
mov dl, bl
|
||||
|
||||
pop bx
|
||||
pop ax
|
||||
ret
|
||||
|
||||
.error:
|
||||
; Do we still have retries remaining?
|
||||
mov si, diskerror_msg
|
||||
dec di
|
||||
jz fatal_error ; No, fail
|
||||
|
||||
; Yes, reset disk
|
||||
xor ah, ah
|
||||
int 0x13
|
||||
|
||||
; Execute the loop again
|
||||
pop cx
|
||||
pop ax
|
||||
jmp .retry
|
||||
|
||||
fatal_error:
|
||||
mov cx, 9
|
||||
.loop:
|
||||
lodsb
|
||||
mov ah, 0xe
|
||||
int 0x10
|
||||
loop .loop
|
||||
|
||||
hang:
|
||||
hlt
|
||||
jmp hang
|
||||
|
||||
|
||||
kernel_cluster dw 0
|
||||
ettinos_kernel_cluster dw 0
|
||||
|
||||
ettinos_kernel_name db "SYSTEM BIN"
|
||||
|
||||
notfound_msg db "No kernel"
|
||||
diskerror_msg db "Disk error"
|
||||
choose_msg db 13, 10, "EttinOS/Nor86?", 0
|
||||
prompt: db "Select OS. 'e' for EttinOS, any other key Nor86.", 0
|
||||
kernel_name: db "KERNEL BIN"
|
||||
ettinos_kernel_name: db "SYSTEM BIN"
|
||||
|
||||
times 510-($-$$) db 0
|
||||
db 0x55, 0xaa
|
||||
39
console.inc
39
console.inc
|
|
@ -1,39 +0,0 @@
|
|||
; IN:
|
||||
; ds:si = start of asciz string
|
||||
printz:
|
||||
push ax
|
||||
push si
|
||||
|
||||
.loop:
|
||||
lodsb
|
||||
test al, al
|
||||
jz .end
|
||||
|
||||
call printc
|
||||
|
||||
jmp .loop
|
||||
|
||||
.end:
|
||||
|
||||
pop si
|
||||
pop ax
|
||||
ret
|
||||
|
||||
; IN:
|
||||
; al = cp437 character
|
||||
printc:
|
||||
push ax
|
||||
|
||||
cmp al, 10
|
||||
jne .output
|
||||
|
||||
mov ax, 0x0e0d
|
||||
int 0x10
|
||||
mov al, 10
|
||||
|
||||
.output:
|
||||
mov ah, 0xe
|
||||
int 0x10
|
||||
|
||||
pop ax
|
||||
ret
|
||||
|
|
@ -0,0 +1,32 @@
|
|||
hexprint16:
|
||||
xchg ah, al
|
||||
call hexprint8
|
||||
xchg ah, al
|
||||
|
||||
hexprint8:
|
||||
push ax
|
||||
push bx
|
||||
push cx
|
||||
mov cl, al
|
||||
xor bx, bx
|
||||
|
||||
mov ah, 0xe
|
||||
shr al, 1
|
||||
shr al, 1
|
||||
shr al, 1
|
||||
shr al, 1
|
||||
mov bl, al
|
||||
mov al, [.digits + bx]
|
||||
int 0x10
|
||||
|
||||
mov bl, 0xf
|
||||
and bl, cl
|
||||
mov al, [.digits + bx]
|
||||
int 0x10
|
||||
|
||||
pop cx
|
||||
pop bx
|
||||
pop ax
|
||||
ret
|
||||
|
||||
.digits: db '0123456789abcdef'
|
||||
46
kernel.asm
46
kernel.asm
|
|
@ -1,50 +1,8 @@
|
|||
cpu 8086
|
||||
org 0x500
|
||||
|
||||
greet:
|
||||
mov si, kernel_greeting
|
||||
call printz
|
||||
|
||||
mov al, dl
|
||||
add al, '0'
|
||||
call printc
|
||||
mov al, 10
|
||||
call printc
|
||||
|
||||
memsize:
|
||||
; Get and display memory size
|
||||
int 0x12
|
||||
mov bx, buffer
|
||||
call itoa
|
||||
|
||||
mov si, bx
|
||||
call printz
|
||||
mov si, memsize_trailer
|
||||
call printz
|
||||
|
||||
floppies:
|
||||
; Get and display number of floppy disks
|
||||
int 0x11
|
||||
times 6 shr ax, 1
|
||||
and ax, 3
|
||||
inc ax
|
||||
|
||||
add al, '0'
|
||||
call printc
|
||||
|
||||
mov si, floppies_trailer
|
||||
call printz
|
||||
mov ax, 0x0e40
|
||||
int 0x10
|
||||
|
||||
hang:
|
||||
hlt
|
||||
jmp hang
|
||||
|
||||
%include "console.inc"
|
||||
%include "printhex.inc"
|
||||
%include "strint.inc"
|
||||
|
||||
kernel_greeting db 10, "Nor86 kernel succesfully loaded", 10, "Loaded from disk ", 0
|
||||
memsize_trailer db "k RAM", 10, 0
|
||||
floppies_trailer db " floppy drive(s)", 10, 0
|
||||
|
||||
buffer times 256 db 0
|
||||
|
|
|
|||
36
printhex.inc
36
printhex.inc
|
|
@ -1,36 +0,0 @@
|
|||
; IN:
|
||||
; ax = hex value
|
||||
printh16:
|
||||
xchg ah, al
|
||||
call printh8
|
||||
xchg ah, al
|
||||
|
||||
; IN:
|
||||
; al = hex value
|
||||
printh8:
|
||||
push ax
|
||||
mov ah, al
|
||||
|
||||
shr al, 1
|
||||
shr al, 1
|
||||
shr al, 1
|
||||
shr al, 1
|
||||
call .printh4
|
||||
|
||||
mov al, 0xf
|
||||
and al, ah
|
||||
call .printh4
|
||||
|
||||
pop ax
|
||||
ret
|
||||
|
||||
.printh4:
|
||||
cmp al, 10
|
||||
jb .numeric
|
||||
|
||||
add al, 'a' - 10
|
||||
jmp printc
|
||||
|
||||
.numeric:
|
||||
add al, '0'
|
||||
jmp printc
|
||||
33
strint.inc
33
strint.inc
|
|
@ -1,33 +0,0 @@
|
|||
; IN:
|
||||
; ax = number to convert
|
||||
; ds:bx = storage buffer
|
||||
; OUT:
|
||||
; ds:bx = start of converted number
|
||||
itoa:
|
||||
push ax
|
||||
push cx
|
||||
push dx
|
||||
|
||||
mov cx, 10
|
||||
|
||||
add bx, 5
|
||||
mov byte [bx], 0
|
||||
|
||||
.convert_loop:
|
||||
test ax, ax
|
||||
jz .end
|
||||
|
||||
xor dx, dx
|
||||
div cx
|
||||
|
||||
add dl, '0'
|
||||
dec bx
|
||||
mov byte [bx], dl
|
||||
|
||||
jmp .convert_loop
|
||||
|
||||
.end:
|
||||
pop dx
|
||||
pop cx
|
||||
pop ax
|
||||
ret
|
||||
Loading…
Reference in New Issue