Compare commits
1 Commits
| Author | SHA1 | Date |
|---|---|---|
Jonas 'Sortie' Termansen
|
dcd9d60271 |
84
EttinOS.svg
84
EttinOS.svg
|
|
@ -1,84 +0,0 @@
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Before Width: | Height: | Size: 6.3 KiB |
|
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@ -1,7 +1,7 @@
|
|||
MIT License
|
||||
===========
|
||||
|
||||
Copyright (c) 2021 CrazyEttin and contributors
|
||||
Copyright (c) 2021 CrazyEttin
|
||||
|
||||
Permission is hereby granted, free of charge, to any person obtaining a
|
||||
copy of this software and associated documentation files (the
|
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|
|
|
|||
97
README.MD
97
README.MD
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@ -1,11 +1,9 @@
|
|||
EttinOS
|
||||
=======
|
||||
|
||||
EttinOS is a minimalist 16-bit hobbyist disk operating system for the
|
||||
IBM Personal Computer and compatible machines. Its git repository can be
|
||||
found at https://ahti.space/git/crazyettin/EttinOS and that of
|
||||
EttinOS-extra, a collection of programs for the system, at
|
||||
https://ahti.space/git/crazyettin/EttinOS-extra.
|
||||
EttinOS is a minimalist 16-bit DOS-like hobbyist operating system for
|
||||
the IBM PC and compatible computers. Its git repository can be found at
|
||||
https://ahti.space/git/crazyettin/EttinOS.
|
||||
|
||||
System requirements
|
||||
-------------------
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||||
|
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@ -13,72 +11,44 @@ System requirements
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|||
* An Intel 8086 or compatible CPU
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* BIOS, or UEFI in legacy mode
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||||
* 64 KiB of RAM
|
||||
* 1-4 floppy disk drives (hard disk drives are not supported)
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||||
* A floppy disk drive
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||||
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||||
Building
|
||||
--------
|
||||
|
||||
Build dependencies:
|
||||
* A Unix-like operating system
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||||
* bash
|
||||
* coreutils
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||||
* dosfstools
|
||||
* mtools
|
||||
* nasm
|
||||
* rw (optional)
|
||||
|
||||
Running make.sh will build EttinOS and create a bootable 360 KiB 5.25"
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||||
floppy disk image named EttinOS.img and a source image of the same
|
||||
format named EttinOS-src.img. To get 1440 KiB 3.5" images instead use
|
||||
the argument -1440. If you want to use another format you will have to
|
||||
build the system manually.
|
||||
floppy disk image named EttinOS.img. To get a 1.44 MB 3.5" one instead
|
||||
use the argument -1440. If you want to use another floppy disk format
|
||||
you will have to adjust the bootloader disk description tables and
|
||||
install the system manually. Hard disk drives are not supported.
|
||||
|
||||
Usage
|
||||
Input
|
||||
-----
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||||
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||||
The input system is inspired by typewriters. Typing a character
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||||
The EttinOS input system is inspired by typewriters. Typing a character
|
||||
overwrites the cursor location and the erase (=tab) key erases it. The
|
||||
space and backspace keys move the cursor.
|
||||
|
||||
EttinOS assigns the drives letters from A to D and uses a version of the
|
||||
MS-DOS 3.0 FAT12 file system (in actual use since 2.1) without support
|
||||
for file attributes and thus disk labels and subdirectories. Drive
|
||||
letters and file names are case-insensitive and the latter follow the
|
||||
8.3 format. Text files use CRLF line endings.
|
||||
|
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Drives and files are specified as ([A-D]:) and ([A-D]:)FILENAME.EXT
|
||||
respectively. Specifying the current drive, indicated in the prompt, is
|
||||
optional.
|
||||
|
||||
A command can be followed by arguments separated from eachother and the
|
||||
command with spaces. Extra spaces are ignored. Commands other than
|
||||
changing the current drive are stored as external programs: the command
|
||||
for a program is its file specification without the extension.
|
||||
|
||||
Commands included in EttinOS:
|
||||
* [A-D]:: Change the current drive.
|
||||
* ECHO: Print a message. Syntax: ECHO Message to be printed
|
||||
* HELLO: Print "Hello world!".
|
||||
* LIST: Print a list of the files on a drive. Syntax: LIST DRIVE
|
||||
* PRINT: Print a text file. Syntax: PRINT FILE
|
||||
|
||||
Both LIST and PRINT page their output if all of it does not fit on the
|
||||
screen at the same time. Press any key other than escape to continue
|
||||
printing after each screen or escape to quit the program.
|
||||
|
||||
Programming
|
||||
-----------
|
||||
|
||||
EttinOS has a flat address space of 64 KiB. The data, stack, and extra
|
||||
segments are set at the beginning of the RAM and the system stack at the
|
||||
end of the address space. Programs are loaded at address 0x3000, the
|
||||
number of the current drive is loaded in DL, and SI is pointed at the
|
||||
command tail (a string ending in a null) when the program is executed.
|
||||
EttinOS has a flat address space of 64 KiB. The data, stack, and
|
||||
extra segments are set at the beginning of the RAM and the system stack
|
||||
at the end of the address space. Programs are loaded at address 0x2000.
|
||||
The stack is reset back to the end of the address space after a program
|
||||
has finished running.
|
||||
|
||||
System calls:
|
||||
* Interrupt 0x20: Return to the shell.
|
||||
* Interrupt 0x21: String operations:
|
||||
* Interrupt 0x21: Input and output:
|
||||
* AH = 0x0: Print a string ending in a null from SI.
|
||||
* AH = 0x1: Read a string ending in a null of at most AL
|
||||
characters to DI until a return.
|
||||
|
|
@ -86,37 +56,8 @@ System calls:
|
|||
CRLF.
|
||||
* AH = 0x3: Read a string ending in a null of at most AL
|
||||
characters to DI until a return and print a CRLF.
|
||||
* AH = 0x4: (Under construction) Convert a decimal string ending
|
||||
in a null at SI to a value in AL.
|
||||
* AH = 0x5: (Under construction) Convert a value in AL to a
|
||||
decimal string ending in a null at DI.
|
||||
* AH = 0x6: (Under construction) Convert a hexadecimal string
|
||||
ending in a null at SI to a value in AL.
|
||||
* AH = 0x7: (Under construction) Convert a value in AL to a
|
||||
hexadecimal string ending in a null at DI.
|
||||
* Interrupt 0x22: Disk operations:
|
||||
* AH = 0x0: (Under construction) Load the directory of a drive
|
||||
named at SI as a string ending in a null to the offset
|
||||
BX and store the error codes in AL:
|
||||
* AL = 0x0: Succesful load
|
||||
* AL = 0x1: Drive not found
|
||||
* AL = 0x2: Unable to read disk
|
||||
* AH = 0x1: (Under construction) Store a directory at the offset
|
||||
BX to a drive named at SI as a string ending in a
|
||||
null.
|
||||
* AH = 0x2: Load a file named at SI as a string ending in a null
|
||||
to the offset BX and store the file size in CX and the
|
||||
error codes in AL:
|
||||
* AL = 0x0: Succesful load
|
||||
* AL = 0x1: Drive not found
|
||||
* AL = 0x2: Unable to read disk
|
||||
* AL = 0x4: File or command not found
|
||||
* AL = 0x8: Not enough memory
|
||||
* AH = 0x3: (Under construction) Save a file.
|
||||
|
||||
Known bugs
|
||||
----------
|
||||
|
||||
* Trying to access a disk of different format than the current one can
|
||||
crash the system.
|
||||
* Files beyond the ~40th one on the disk might not load properly.
|
||||
* AH = 0x0: Load a file named in SI as a string ending in a null
|
||||
to the offset BX and set AL to 0x0 if the load was
|
||||
succesfull and 0x1 if there was an error.
|
||||
* AH = 0x1: Save a file (under construction).
|
||||
|
|
|
|||
41
make.sh
41
make.sh
|
|
@ -1,8 +1,10 @@
|
|||
#!/bin/sh
|
||||
|
||||
rm -f EttinOS.img
|
||||
rm -f EttinOS-src.img
|
||||
mkdir -p bin
|
||||
if [ ! -d "bin" ]
|
||||
then
|
||||
mkdir bin
|
||||
fi
|
||||
|
||||
cd src/
|
||||
if [ "$1" = "-1440" ]
|
||||
|
|
@ -10,42 +12,15 @@ if [ "$1" = "-1440" ]
|
|||
else nasm BOOT.ASM -f bin -o ../bin/BOOT.BIN
|
||||
fi
|
||||
nasm SYSTEM.ASM -f bin -o ../bin/SYSTEM.BIN
|
||||
nasm ECHO.ASM -f bin -o ../bin/ECHO.BIN
|
||||
nasm HELLO.ASM -f bin -o ../bin/HELLO.BIN
|
||||
nasm LIST.ASM -f bin -o ../bin/LIST.BIN
|
||||
nasm PRINT.ASM -f bin -o ../bin/PRINT.BIN
|
||||
|
||||
cd ..
|
||||
if [ "$1" = "-1440" ]
|
||||
then
|
||||
mkfs.fat -C EttinOS.img 1440 1>/dev/null
|
||||
mkfs.fat -C EttinOS-src.img 1440 1>/dev/null
|
||||
else
|
||||
mkfs.fat -C EttinOS.img 360 1>/dev/null
|
||||
mkfs.fat -C EttinOS-src.img 360 1>/dev/null
|
||||
fi
|
||||
|
||||
if which rw > /dev/null 2>&1
|
||||
then rw -i bin/BOOT.BIN -o EttinOS.img -b 512 -c 1x
|
||||
else dd if=bin/BOOT.BIN of=EttinOS.img conv=notrunc bs=512 count=1 1>/dev/null
|
||||
then mkfs.fat -C EttinOS.img 1440
|
||||
else mkfs.fat -C EttinOS.img 360
|
||||
fi
|
||||
rw -i bin/BOOT.BIN -o EttinOS.img -b 512 -c 1x
|
||||
mcopy -i EttinOS.img bin/SYSTEM.BIN ::
|
||||
mcopy -i EttinOS.img bin/HELLO.BIN ::
|
||||
mcopy -i EttinOS.img README.MD ::
|
||||
mcopy -i EttinOS.img LICENSE.MD ::
|
||||
mcopy -i EttinOS.img bin/ECHO.BIN ::
|
||||
mcopy -i EttinOS.img bin/HELLO.BIN ::
|
||||
mcopy -i EttinOS.img bin/LIST.BIN ::
|
||||
mcopy -i EttinOS.img bin/PRINT.BIN ::
|
||||
|
||||
mcopy -i EttinOS-src.img src/BOOT.ASM ::
|
||||
mcopy -i EttinOS-src.img src/SYSTEM.ASM ::
|
||||
mcopy -i EttinOS-src.img src/PRINTSTR.INC ::
|
||||
mcopy -i EttinOS-src.img src/READSTR.INC ::
|
||||
mcopy -i EttinOS-src.img src/PRINTLN.INC ::
|
||||
mcopy -i EttinOS-src.img src/READLN.INC ::
|
||||
mcopy -i EttinOS-src.img README.MD ::
|
||||
mcopy -i EttinOS-src.img LICENSE.MD ::
|
||||
mcopy -i EttinOS-src.img src/ECHO.ASM ::
|
||||
mcopy -i EttinOS-src.img src/HELLO.ASM ::
|
||||
mcopy -i EttinOS-src.img src/LIST.ASM ::
|
||||
mcopy -i EttinOS-src.img src/PRINT.ASM ::
|
||||
|
|
|
|||
238
src/BOOT.ASM
238
src/BOOT.ASM
|
|
@ -1,136 +1,120 @@
|
|||
cpu 8086
|
||||
org 0x7c00
|
||||
CPU 8086
|
||||
ORG 0x7c00
|
||||
|
||||
;Jump to the code
|
||||
jmp start
|
||||
|
||||
;Padding
|
||||
nop
|
||||
|
||||
;OEM label
|
||||
db "ETTINOS "
|
||||
;Disk description tables
|
||||
|
||||
%ifdef F1440
|
||||
|
||||
;1.44 MB 3.5" floppy disk BPB (enable with the argument -d F1440)
|
||||
;1.44 MB 3.5" floppy disk (enable with the argument -d F1440 when building)
|
||||
oemlabel db "ETTINOS "
|
||||
sectorsize dw 0x200 ;bytes
|
||||
clustersize db 0x1 ;sectors
|
||||
reservedsectors dw 0x1
|
||||
bootsectors dw 0x1
|
||||
fats db 0x2
|
||||
rootentries dw 0xe0
|
||||
logicalsectors dw 0xb40
|
||||
mediadescriptor db 0xf0
|
||||
sectorsperfat dw 0x9
|
||||
sectorspertrack dw 0x12
|
||||
heads dw 0x2
|
||||
hiddensectors dw 0x0
|
||||
sides dw 0x2
|
||||
hiddensectors dd 0x0
|
||||
largesectors dd 0x0
|
||||
driveid dw 0x0
|
||||
drivesignature db 0x29
|
||||
volumeid dd 0x0
|
||||
volumelabel db "ETTINOS "
|
||||
filesystem db "FAT12 "
|
||||
|
||||
%else
|
||||
|
||||
;360 KiB 5.25" floppy disk BPB (default)
|
||||
;360 KiB 5.25" floppy disk (default)
|
||||
oemlabel db "ETTINOS "
|
||||
sectorsize dw 0x200 ;bytes
|
||||
clustersize db 0x2 ;sectors
|
||||
reservedsectors dw 0x1
|
||||
bootsectors dw 0x1
|
||||
fats db 0x2
|
||||
rootentries dw 0x70
|
||||
logicalsectors dw 0x2d0
|
||||
mediadescriptor db 0xfd
|
||||
sectorsperfat dw 0x2
|
||||
sectorspertrack dw 0x9
|
||||
heads dw 0x2
|
||||
hiddensectors dw 0x0
|
||||
sides dw 0x2
|
||||
hiddensectors dd 0x0
|
||||
largesectors dd 0x0
|
||||
driveid dw 0x0
|
||||
drivesignature db 0x29
|
||||
volumeid dd 0x0
|
||||
volumelabel db "ETTINOS "
|
||||
filesystem db "FAT12 "
|
||||
|
||||
%endif
|
||||
|
||||
;Setup
|
||||
;Set the segments
|
||||
start:
|
||||
|
||||
;Setup
|
||||
;Set up the data, stack, and extra segments
|
||||
mov ax, 0x0
|
||||
mov ds, ax
|
||||
mov ss, ax
|
||||
mov es, ax
|
||||
;Set the stack
|
||||
;Set up the stack
|
||||
cli
|
||||
mov sp, 0x0
|
||||
sti
|
||||
;Store the boot drive number
|
||||
mov [drive], dl
|
||||
mov [bootdrive], dl
|
||||
|
||||
;Calculate and store variables not found in the BPB
|
||||
;Start of the root
|
||||
;Load the root
|
||||
;Set the source
|
||||
mov ah, 0x0
|
||||
mov al, [fats]
|
||||
mul word [sectorsperfat]
|
||||
add ax, [reservedsectors]
|
||||
mov [rootstart], ax
|
||||
;Size of the root in sectors
|
||||
add ax, [bootsectors]
|
||||
push ax
|
||||
call calcsource
|
||||
;Set the destination
|
||||
mov si, buffer
|
||||
mov bx, si
|
||||
;Set the size
|
||||
push dx
|
||||
mov ax, [rootentries]
|
||||
mov dx, 0x20
|
||||
mul dx
|
||||
mov dx, 0x0
|
||||
div word [sectorsize]
|
||||
mov [rootsectors], ax
|
||||
;Start of data
|
||||
add ax, [rootstart]
|
||||
mov [datastart], ax
|
||||
|
||||
;Load the root
|
||||
;Set the source
|
||||
mov ax, [rootstart]
|
||||
;Set the destination
|
||||
mov si, buffer
|
||||
mov bx, si
|
||||
;Set the size
|
||||
mov cx, [rootsectors]
|
||||
;Store the source and the loop counter in the stack
|
||||
loadrootsector:
|
||||
pop dx
|
||||
push ax
|
||||
push cx
|
||||
;Set the source
|
||||
call calcsource
|
||||
;Set the size
|
||||
mov al, 0x1
|
||||
;Load a sector
|
||||
;Load
|
||||
mov ah, 0x2
|
||||
int 0x13
|
||||
;Load the loop counter and the source from the stack
|
||||
pop cx
|
||||
pop ax
|
||||
;Set the next sector
|
||||
add ax, 0x1
|
||||
add bx, word [sectorsize]
|
||||
;Load the next sector
|
||||
loop loadrootsector
|
||||
|
||||
;Search the root for the system entry
|
||||
;Set DI to the root
|
||||
mov di, buffer
|
||||
;Set the number of root entries
|
||||
;Initialise the search loop
|
||||
mov cx, word [rootentries]
|
||||
;Set the entry pointer
|
||||
mov ax, 0x0
|
||||
;Store the loop counter in the stack
|
||||
search:
|
||||
;Store CX in the stack
|
||||
push cx
|
||||
;Check for the system entry
|
||||
mov si, file
|
||||
mov si, sysfile
|
||||
mov cx, 0xb
|
||||
rep cmpsb
|
||||
je loadfat
|
||||
;Set DI at the next entry
|
||||
je loadentry
|
||||
;Set DI to the next entry
|
||||
add ax, 0x20
|
||||
mov di, buffer
|
||||
add di, ax
|
||||
;Load the loop counter from the stack
|
||||
;Load CX from the stack
|
||||
pop cx
|
||||
;Search the next entry
|
||||
loop search
|
||||
|
||||
;Print an error message and hang if the system is not found
|
||||
;Set SI at the file error message
|
||||
mov si, filerrormsg
|
||||
;Print an error message if the system is not found
|
||||
mov si, errormsg
|
||||
printerror:
|
||||
;Load a character
|
||||
printstr:
|
||||
lodsb
|
||||
;Check for the string end
|
||||
cmp al, 0x0
|
||||
|
|
@ -138,61 +122,53 @@ je $
|
|||
;Print the character
|
||||
mov ah, 0xe
|
||||
int 0x10
|
||||
;Print the next character
|
||||
jmp printstr
|
||||
;Repeat
|
||||
jmp printerror
|
||||
|
||||
;Load the FAT
|
||||
;Load the system entry
|
||||
loadentry:
|
||||
;Load CX from the stack
|
||||
loadfat:
|
||||
pop cx
|
||||
;Store the address of the first cluster
|
||||
mov ax, [di + 0xf]
|
||||
mov [cluster], ax
|
||||
;Store the first cluster
|
||||
mov ax, word [es:di+0xf]
|
||||
mov word [cluster], ax
|
||||
;Set the source
|
||||
mov ax, [reservedsectors]
|
||||
mov ax, 0x1
|
||||
call calcsource
|
||||
;Set the destination
|
||||
mov bx, buffer
|
||||
mov di, buffer
|
||||
mov bx, di
|
||||
;Set the size
|
||||
mov ax, [sectorsperfat]
|
||||
;Load the FAT
|
||||
;Load
|
||||
mov ah, 0x2
|
||||
int 0x13
|
||||
|
||||
;Load the system file
|
||||
|
||||
;Load a cluster
|
||||
loadcluster:
|
||||
;Set the source
|
||||
pop cx
|
||||
pop bx
|
||||
mov ax, word [cluster]
|
||||
sub ax, 0x2
|
||||
mul byte [clustersize]
|
||||
add ax, [datastart]
|
||||
add ax, bx
|
||||
add ax, cx
|
||||
push bx
|
||||
push cx
|
||||
call calcsource
|
||||
;Set the destination
|
||||
mov bx, word [pointer]
|
||||
;Set the size
|
||||
mov ch, 0x0
|
||||
mov cl, byte [clustersize]
|
||||
;Store the loop counter in the stack
|
||||
loadclustersector:
|
||||
push cx
|
||||
;Set the source
|
||||
call calcsource
|
||||
;Set the size
|
||||
push ax
|
||||
mov al, 0x1
|
||||
;Load a sector
|
||||
;mov al, 0x1
|
||||
mov al, [clustersize]
|
||||
;Load
|
||||
mov ah, 0x2
|
||||
int 0x13
|
||||
pop ax
|
||||
;Set the next sector
|
||||
add ax, 0x1
|
||||
add bx, [sectorsize]
|
||||
;Load the loop counter from the stack
|
||||
pop cx
|
||||
;Load the next sector
|
||||
loop loadclustersector
|
||||
|
||||
;Calculate the next cluster
|
||||
;Check if the cluster is even or odd
|
||||
mov ax, [cluster]
|
||||
mov dx, 0x0
|
||||
mov bx, 0x3
|
||||
|
|
@ -201,87 +177,65 @@ mov bx, 0x2
|
|||
div bx
|
||||
mov si, buffer
|
||||
add si, ax
|
||||
mov ax, word [si]
|
||||
mov ax, word [ds:si]
|
||||
or dx, dx
|
||||
jz even
|
||||
;If the cluster is odd shift out the first four bits
|
||||
times 0x4 shr ax, 0x1
|
||||
odd:
|
||||
shr ax, 1
|
||||
shr ax, 1
|
||||
shr ax, 1
|
||||
shr ax, 1
|
||||
jmp contcalc
|
||||
;If the cluster is even mask out the final four bits
|
||||
even:
|
||||
and ax, 0xfff
|
||||
contcalc:
|
||||
;Check for the file end
|
||||
mov word [cluster], ax
|
||||
cmp ax, 0xff8
|
||||
jge boot
|
||||
;Store the address of the next cluster
|
||||
mov word [cluster], ax
|
||||
;Set the destination of the next cluster
|
||||
mov ax, [sectorsize]
|
||||
mul word [clustersize]
|
||||
add word [pointer], ax
|
||||
;Load the next cluster
|
||||
jmp loadcluster
|
||||
|
||||
;Boot the system
|
||||
;Pass the boot drive number to the system
|
||||
;Clear the stack and boot the system
|
||||
boot:
|
||||
mov dl, byte [drive]
|
||||
;Boot the system
|
||||
;Clear
|
||||
pop cx
|
||||
pop bx
|
||||
;Boot
|
||||
jmp 0x0:0x500
|
||||
|
||||
;Data
|
||||
drive db 0x0
|
||||
rootstart dw 0x0
|
||||
rootsectors dw 0x0
|
||||
datastart dw 0x0
|
||||
file db "SYSTEM BIN"
|
||||
filerrormsg db "System not found", 0xd, 0xa, 0x0
|
||||
cluster dw 0x0
|
||||
pointer dw 0x500
|
||||
|
||||
;***
|
||||
bootdrive db 0x0
|
||||
sysfile db "SYSTEM BIN"
|
||||
errormsg db "System not found", 0xd, 0xa, 0x0
|
||||
cluster dw 0x0
|
||||
pointer dw 0x500
|
||||
|
||||
;Calculate the source arguments for loading data from the disk
|
||||
calcsource:
|
||||
|
||||
;Store AX and BX in the stack
|
||||
push ax
|
||||
push bx
|
||||
|
||||
;Calculate the cylinder, head, and sector
|
||||
;Store the logical sector in BX
|
||||
mov bx, ax
|
||||
;Calculate the sector
|
||||
mov dx, 0x0
|
||||
div word [sectorspertrack]
|
||||
add dl, 0x1
|
||||
mov cl, dl
|
||||
;Load the logical sector from BX
|
||||
mov ax, bx
|
||||
;Calculate the head and cylinder
|
||||
mov dx, 0x0
|
||||
div word [sectorspertrack]
|
||||
mov dx, 0x0
|
||||
div word [heads]
|
||||
mov dh, dl ;Head
|
||||
mov ch, al ;Cylinder
|
||||
|
||||
;Load the boot drive number
|
||||
mov dl, byte [drive]
|
||||
|
||||
;Load BX and AX from the stack
|
||||
div word [sides]
|
||||
mov dh, dl
|
||||
mov ch, al
|
||||
pop bx
|
||||
pop ax
|
||||
|
||||
;Return
|
||||
mov dl, byte [bootdrive]
|
||||
ret
|
||||
|
||||
;***
|
||||
|
||||
;Pad the binary to a full sector and make the disk bootable
|
||||
;Padding
|
||||
times 0x1fe-($-$$) db 0x0
|
||||
|
||||
;Boot signature
|
||||
dw 0xaa55
|
||||
|
||||
|
|
|
|||
14
src/ECHO.ASM
14
src/ECHO.ASM
|
|
@ -1,14 +0,0 @@
|
|||
cpu 8086
|
||||
org 0x3000
|
||||
|
||||
;Check for an empty tail
|
||||
cmp byte [si], 0x0
|
||||
je done
|
||||
|
||||
;Print the message
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
|
||||
;Return to the system
|
||||
done:
|
||||
int 0x20
|
||||
|
|
@ -1,13 +1,11 @@
|
|||
cpu 8086
|
||||
org 0x3000
|
||||
CPU 8086
|
||||
ORG 0x2000
|
||||
|
||||
;Print a hello world.
|
||||
mov si, hello
|
||||
;Prints a hello world.
|
||||
mov si, .hello
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
|
||||
;Return to the system
|
||||
int 0x20
|
||||
|
||||
;Data
|
||||
hello db "Hello world!", 0x0
|
||||
.hello db "Hello world!", 0x0
|
||||
|
|
|
|||
264
src/LIST.ASM
264
src/LIST.ASM
|
|
@ -1,264 +0,0 @@
|
|||
cpu 8086
|
||||
org 0x3000
|
||||
|
||||
;Store the drive number
|
||||
mov [drive], dl
|
||||
|
||||
;Check for an empty tail
|
||||
cmp byte [si], 0x0
|
||||
je loadvalues
|
||||
|
||||
;Change the drive if needed
|
||||
;Check for a drive specification
|
||||
cmp byte [si + 0x1], ":"
|
||||
jne driverror
|
||||
cmp byte [si + 0x2], 0x0
|
||||
je changedrive
|
||||
cmp byte [si + 0x2], 0x20
|
||||
je changedrive
|
||||
;Print an error message
|
||||
jmp driverror
|
||||
changedrive:
|
||||
;Get the BIOS equipment list
|
||||
int 0x11
|
||||
;Get the number of floppy drives
|
||||
times 0x6 shr ax, 0x1
|
||||
and ax, 0x3
|
||||
inc ax
|
||||
;Set the loop and drive letter counters and the drive letter and number
|
||||
mov cx, ax
|
||||
mov di, driveletters
|
||||
mov al, [si]
|
||||
mov dl, 0x0
|
||||
;Check which drive to change to
|
||||
checkdrive:
|
||||
cmp al, [di]
|
||||
je contchdrive
|
||||
inc di
|
||||
cmp al, [di]
|
||||
je contchdrive
|
||||
inc di
|
||||
inc dl
|
||||
loop checkdrive
|
||||
;Print an error message
|
||||
jmp driverror
|
||||
;Change the drive
|
||||
contchdrive:
|
||||
mov [drive], dl
|
||||
|
||||
;Load the disk description table
|
||||
;Set the source
|
||||
loadvalues:
|
||||
mov dl, [drive]
|
||||
mov ch, 0x0
|
||||
mov dh, 0x0
|
||||
mov cl, 0x1
|
||||
;Set the destination
|
||||
mov si, buffer
|
||||
mov bx, si
|
||||
;Set the size
|
||||
mov al, 0x1
|
||||
;Load the disk description table
|
||||
mov ah, 0x2
|
||||
int 0x13
|
||||
jc diskerror
|
||||
|
||||
;Store the disk values used for the rest of the call
|
||||
mov ax, [buffer + 0xb]
|
||||
mov [sectorsize], ax
|
||||
mov ax, [buffer + 0xe]
|
||||
mov [reservedsectors], ax
|
||||
mov al, [buffer + 0x10]
|
||||
mov [fats], al
|
||||
mov ax, [buffer + 0x11]
|
||||
mov [rootentries], ax
|
||||
mov ax, [buffer + 0x16]
|
||||
mov [sectorsperfat], ax
|
||||
mov ax, [buffer + 0x18]
|
||||
mov [sectorspertrack], ax
|
||||
mov ax, [buffer + 0x1a]
|
||||
mov [heads], ax
|
||||
|
||||
;Calculate and store variables not found in the BPB
|
||||
;Start of the root
|
||||
mov ah, 0x0
|
||||
mov al, [fats]
|
||||
mul word [sectorsperfat]
|
||||
add ax, [reservedsectors]
|
||||
mov [rootstart], ax
|
||||
;Size of the root in sectors
|
||||
mov ax, [rootentries]
|
||||
mov dx, 0x20
|
||||
mul dx
|
||||
mov dx, 0x0
|
||||
div word [sectorsize]
|
||||
mov [rootsectors], ax
|
||||
|
||||
;Load the root
|
||||
;Set the source
|
||||
mov ax, [rootstart]
|
||||
;Set the destination
|
||||
mov si, buffer
|
||||
mov bx, si
|
||||
;Set the size
|
||||
mov cx, [rootsectors]
|
||||
;Store the source and the loop counter in the stack
|
||||
loadrootsector:
|
||||
push ax
|
||||
push cx
|
||||
;Set the source
|
||||
call calcsource
|
||||
;Set the size
|
||||
mov al, 0x1
|
||||
;Load a sector
|
||||
mov ah, 0x2
|
||||
int 0x13
|
||||
;Load the loop counter and the source from the stack
|
||||
pop cx
|
||||
pop ax
|
||||
;Set the next sector
|
||||
add ax, 0x1
|
||||
add bx, word [sectorsize]
|
||||
loop loadrootsector
|
||||
|
||||
;List
|
||||
;Set SI to the root
|
||||
mov si, buffer
|
||||
;Initialise the loop
|
||||
mov cx, word [rootentries]
|
||||
mov ax, 0x0
|
||||
mov bl, 0x17
|
||||
;Store CX in the stack
|
||||
loop:
|
||||
push cx
|
||||
;Check for an empty entry
|
||||
cmp byte [si], 0xe5
|
||||
je skip
|
||||
;Check for the end of entries
|
||||
cmp byte [si], 0x0
|
||||
je done
|
||||
;store AX in the stack
|
||||
push ax
|
||||
;Print the main part of the name
|
||||
mov cx, 0x8
|
||||
push ax
|
||||
printname:
|
||||
mov al, [si]
|
||||
mov ah, 0xe
|
||||
int 0x10
|
||||
inc si
|
||||
loop printname
|
||||
;Print a space
|
||||
mov al, 0x20
|
||||
mov ah, 0xe
|
||||
int 0x10
|
||||
;Print the extension
|
||||
mov cx, 0x3
|
||||
printext:
|
||||
mov al, [si]
|
||||
mov ah, 0xe
|
||||
int 0x10
|
||||
inc si
|
||||
loop printext
|
||||
;Print a newline
|
||||
mov al, 0xd
|
||||
mov ah, 0xe
|
||||
int 0x10
|
||||
mov al, 0xa
|
||||
mov ah, 0xe
|
||||
int 0x10
|
||||
;Load AX from the stack
|
||||
pop ax
|
||||
;Check paging
|
||||
cmp bl, 0x0
|
||||
jz page
|
||||
dec bl
|
||||
;Set SI to the next entry
|
||||
skip:
|
||||
add ax, 0x20
|
||||
mov si, buffer
|
||||
add si, ax
|
||||
;Load CX from the stack
|
||||
pop cx
|
||||
loop loop
|
||||
page:
|
||||
push ax
|
||||
mov ah, 0x0
|
||||
int 0x16
|
||||
cmp al, 0x1b
|
||||
je done
|
||||
pop ax
|
||||
mov bl, 0x17
|
||||
jmp skip
|
||||
|
||||
done:
|
||||
int 0x20
|
||||
|
||||
driverror:
|
||||
mov si, driverrormsg
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
jmp done
|
||||
|
||||
diskerror:
|
||||
mov si, diskerrormsg
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
jmp done
|
||||
|
||||
;Data
|
||||
drive db 0x0
|
||||
sectorsize dw 0x0 ;bytes
|
||||
reservedsectors dw 0x0
|
||||
fats db 0x0
|
||||
rootentries dw 0x0
|
||||
sectorsperfat dw 0x0
|
||||
sectorspertrack dw 0x0
|
||||
heads dw 0x0
|
||||
rootstart dw 0x0
|
||||
rootsectors dw 0x0
|
||||
driveletters db "AaBbCcDd"
|
||||
driverrormsg db "Drive not found", 0x0
|
||||
diskerrormsg db "Unable to read disk", 0x0
|
||||
|
||||
;***
|
||||
|
||||
;Calculate the source arguments for loading data from the disk
|
||||
calcsource:
|
||||
|
||||
;Store AX and BX in the stack
|
||||
push ax
|
||||
push bx
|
||||
|
||||
;Calculate the cylinder, head, and sector
|
||||
;Store the logical sector in BX
|
||||
mov bx, ax
|
||||
;Calculate the sector
|
||||
mov dx, 0x0
|
||||
div word [sectorspertrack]
|
||||
add dl, 0x1
|
||||
mov cl, dl
|
||||
;Load the logical sector from BX
|
||||
mov ax, bx
|
||||
;Calculate the head and cylinder
|
||||
mov dx, 0x0
|
||||
div word [sectorspertrack]
|
||||
mov dx, 0x0
|
||||
div word [heads]
|
||||
mov dh, dl ;Head
|
||||
mov ch, al ;Cylinder
|
||||
|
||||
;Load the drive number
|
||||
mov dl, byte [drive]
|
||||
|
||||
;Load BX and AX from the stack
|
||||
pop bx
|
||||
pop ax
|
||||
|
||||
;Return
|
||||
ret
|
||||
|
||||
;***
|
||||
|
||||
;Buffer
|
||||
buffer:
|
||||
390
src/LOADF.INC
390
src/LOADF.INC
|
|
@ -1,91 +1,48 @@
|
|||
;Load a file named at SI as a string ending in a null to the offset BX
|
||||
;and store the file size in CX and the error codes in AL:
|
||||
; * AL = 0x0: Succesful load
|
||||
; * AL = 0x1: Drive not found
|
||||
; * AL = 0x2: Unable to read disk
|
||||
; * AL = 0x4: File or command not found
|
||||
; * AL = 0x8: Not enough memory
|
||||
;Load a file named in SI as a string ending in a null to the offset BX and set AL to 0x0 if the load was succesful and 0x1 if there was an error.
|
||||
|
||||
loadf:
|
||||
|
||||
;Store BX, DX, SI, and DI in the stack
|
||||
;Store the initial registers in the stack
|
||||
push ax
|
||||
push bx
|
||||
push cx
|
||||
push dx
|
||||
push si
|
||||
push di
|
||||
|
||||
;Store the current drive and offset
|
||||
;Store the offset
|
||||
mov word [.pointer], bx
|
||||
mov dl, byte [curdrive]
|
||||
mov byte [drive], dl
|
||||
|
||||
;Change the drive if needed
|
||||
;Check for a drive specification
|
||||
cmp byte [si + 0x1], ":"
|
||||
jne .convert
|
||||
;Get the BIOS equipment list
|
||||
int 0x11
|
||||
;Get the number of floppy drives
|
||||
times 0x6 shr ax, 0x1
|
||||
and ax, 0x3
|
||||
inc ax
|
||||
;Set the loop and drive letter counters and the drive letter and number
|
||||
mov cx, ax
|
||||
mov di, driveletters
|
||||
mov al, [si]
|
||||
mov dl, 0x0
|
||||
;Check which drive to change to
|
||||
.checkdrive:
|
||||
cmp al, [di]
|
||||
je .contchdrive
|
||||
inc di
|
||||
cmp al, [di]
|
||||
je .contchdrive
|
||||
inc di
|
||||
inc dl
|
||||
loop .checkdrive
|
||||
;Set AL to 0x1, CX to 0x0, and print an error message
|
||||
mov si, .driverrormsg
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
mov al, 0x1
|
||||
mov cx, 0x0
|
||||
jmp .done
|
||||
;Change the drive
|
||||
.contchdrive:
|
||||
mov [drive], dl
|
||||
;Move to the file name
|
||||
add si, 0x2
|
||||
|
||||
;Set DI at .file and initialise it with spaces
|
||||
.convert:
|
||||
mov di, .file
|
||||
mov cx, 0xb
|
||||
mov al, 0x20
|
||||
rep stosb
|
||||
sub di, 0xb
|
||||
|
||||
;Convert the main part of the file name into FAT format
|
||||
;Set the length counter
|
||||
;Convert .file into FAT formatting
|
||||
|
||||
;Initialise the length counter for the main part of the name
|
||||
mov bl, 0x8
|
||||
;Load a character
|
||||
|
||||
;Convert the main part of the file name
|
||||
.nameloop:
|
||||
;Load a character
|
||||
lodsb
|
||||
;Check for a period
|
||||
cmp al, 0x2e
|
||||
je .initext
|
||||
;Check for everything else and convert to upper case
|
||||
call .checkconv
|
||||
;Load the next character
|
||||
jmp .nameloop
|
||||
|
||||
;Convert the extension into FAT format
|
||||
;Set DI and the length counter for the extension
|
||||
;Convert the extension
|
||||
.initext:
|
||||
;Set DI and initialise the length counter for the extension
|
||||
mov bl, 0x3
|
||||
mov di, .file+0x8
|
||||
;Load a character
|
||||
.extloop:
|
||||
;Load a character
|
||||
lodsb
|
||||
;Check for a period
|
||||
push ax
|
||||
|
|
@ -94,223 +51,119 @@ je .error
|
|||
pop ax
|
||||
;Check for everything else and convert to upper case
|
||||
call .checkconv
|
||||
;Load the next character
|
||||
jmp .extloop
|
||||
;Set AL to 0x4, CX to 0x0, and print an error message
|
||||
|
||||
;Set the carry flag and print an error message if the file name is invalid
|
||||
.error:
|
||||
pop ax
|
||||
mov si, .filerrormsg
|
||||
stc
|
||||
mov si, .errormsg
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
mov al, 0x4
|
||||
mov cx, 0x0
|
||||
jmp .done
|
||||
|
||||
;Find and load the file
|
||||
|
||||
.load:
|
||||
pop ax
|
||||
|
||||
;Load the disk description table
|
||||
;Load the root
|
||||
;Set the source
|
||||
mov dl, [drive]
|
||||
mov ch, 0x0
|
||||
mov dh, 0x0
|
||||
mov cl, 0x1
|
||||
mov ah, 0x0
|
||||
mov al, [.fats]
|
||||
mul word [.sectorsperfat]
|
||||
add ax, [.bootsectors]
|
||||
push ax
|
||||
call .calcsource
|
||||
;Set the destination
|
||||
mov si, buffer
|
||||
mov bx, si
|
||||
;Set the size
|
||||
mov al, 0x1
|
||||
;Load the disk description table
|
||||
mov ah, 0x2
|
||||
int 0x13
|
||||
jnc .storevalues
|
||||
;Set AL to 0x2, CX to 0x0, and print an error message
|
||||
mov si, .diskerrormsg
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
mov al, 0x2
|
||||
mov cx, 0x0
|
||||
jmp .done
|
||||
|
||||
;Store the disk values used for the rest of the call
|
||||
.storevalues:
|
||||
mov ax, [buffer + 0xb]
|
||||
mov [sectorsize], ax
|
||||
mov al, [buffer + 0xd]
|
||||
mov [clustersize], al
|
||||
mov ax, [buffer + 0xe]
|
||||
mov [reservedsectors], ax
|
||||
mov al, [buffer + 0x10]
|
||||
mov [fats], al
|
||||
mov ax, [buffer + 0x11]
|
||||
mov [rootentries], ax
|
||||
mov ax, [buffer + 0x16]
|
||||
mov [sectorsperfat], ax
|
||||
mov ax, [buffer + 0x18]
|
||||
mov [sectorspertrack], ax
|
||||
mov ax, [buffer + 0x1a]
|
||||
mov [heads], ax
|
||||
|
||||
;Calculate and store variables not found in the BPB
|
||||
;Start of the root
|
||||
mov ah, 0x0
|
||||
mov al, [fats]
|
||||
mul word [sectorsperfat]
|
||||
add ax, [reservedsectors]
|
||||
mov [rootstart], ax
|
||||
;Size of the root in sectors
|
||||
mov ax, [rootentries]
|
||||
push dx
|
||||
mov ax, [.rootentries]
|
||||
mov dx, 0x20
|
||||
mul dx
|
||||
mov dx, 0x0
|
||||
div word [sectorsize]
|
||||
mov [rootsectors], ax
|
||||
;Start of data
|
||||
add ax, [rootstart]
|
||||
mov [datastart], ax
|
||||
|
||||
;Load the root
|
||||
;Set the source
|
||||
mov ax, [rootstart]
|
||||
;Set the destination
|
||||
mov si, buffer
|
||||
mov bx, si
|
||||
;Set the size
|
||||
mov cx, [rootsectors]
|
||||
;Store the source and the loop counter in the stack
|
||||
.loadrootsector:
|
||||
div word [.sectorsize]
|
||||
pop dx
|
||||
push ax
|
||||
push cx
|
||||
;Set the source
|
||||
call .calcsource
|
||||
;Set the size
|
||||
mov al, 0x1
|
||||
;Load a sector
|
||||
;Load
|
||||
mov ah, 0x2
|
||||
int 0x13
|
||||
;Load the loop counter and the source from the stack
|
||||
pop cx
|
||||
pop ax
|
||||
;Set the next sector
|
||||
add ax, 0x1
|
||||
add bx, word [sectorsize]
|
||||
;Load the next sector
|
||||
loop .loadrootsector
|
||||
|
||||
;Search the root for the file entry
|
||||
;Set DI to the root
|
||||
mov di, buffer
|
||||
;Set the number of root entries
|
||||
mov cx, word [rootentries]
|
||||
;Set the entry pointer
|
||||
;Initialise the search loop
|
||||
mov cx, word [.rootentries]
|
||||
mov ax, 0x0
|
||||
;Store the loop counter in the stack
|
||||
.search:
|
||||
;Store CX in the stack
|
||||
push cx
|
||||
;Check for the file entry
|
||||
mov si, .file
|
||||
mov cx, 0xb
|
||||
rep cmpsb
|
||||
je .checksize
|
||||
;Set DI at the next entry
|
||||
je .loadentry
|
||||
;Set DI to the next entry
|
||||
add ax, 0x20
|
||||
mov di, buffer
|
||||
add di, ax
|
||||
;Load the loop counter from the stack
|
||||
pop cx
|
||||
;Search the next entry
|
||||
loop .search
|
||||
;Set AL to 0x4, CX to 0x0, and print an error message
|
||||
mov si, .filerrormsg
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
mov al, 0x4
|
||||
mov cx, 0x0
|
||||
jmp .done
|
||||
|
||||
;Check and store the file size
|
||||
;Load CX from the stack
|
||||
.checksize:
|
||||
pop cx
|
||||
;Check for files larger than 64 KiB
|
||||
cmp word [di + 0x13], 0x0
|
||||
jne .sizerror
|
||||
;Get the cluster size in bytes
|
||||
mov ah, 0x0
|
||||
mov al, [clustersize]
|
||||
mul word [sectorsize]
|
||||
mov bx, ax
|
||||
;Store the file size
|
||||
mov ax, [di + 0x11]
|
||||
mov word [.size], ax
|
||||
;Check for files smaller than 64 KiB but too large to fit into memory
|
||||
jc .sizerror
|
||||
dec ax
|
||||
mov dx, 0x0
|
||||
div bx
|
||||
mul bx
|
||||
add ax, [.pointer]
|
||||
jnc .loadfat
|
||||
;Set AL to 0x8, CX to 0x0, and print an error message
|
||||
.sizerror:
|
||||
mov si, .sizerrormsg
|
||||
loop .search
|
||||
|
||||
;Set the carry flag and print an error message if the file is not found
|
||||
stc
|
||||
mov si, .errormsg
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
mov al, 0x8
|
||||
mov cx, 0x0
|
||||
jmp .done
|
||||
jmp .clearstack
|
||||
|
||||
;Load the FAT
|
||||
.loadfat:
|
||||
;Store the address of the first cluster
|
||||
mov ax, [di + 0xf]
|
||||
mov [.cluster], ax
|
||||
;Load the file entry
|
||||
.loadentry:
|
||||
;Load CX from the stack
|
||||
pop cx
|
||||
;Store the first cluster
|
||||
mov ax, word [es:di+0xf]
|
||||
mov word [.cluster], ax
|
||||
;Set the source
|
||||
mov ax, [reservedsectors]
|
||||
mov ax, 0x1
|
||||
call .calcsource
|
||||
;Set the destination
|
||||
mov bx, buffer
|
||||
mov di, buffer
|
||||
mov bx, di
|
||||
;Set the size
|
||||
mov ax, [sectorsperfat]
|
||||
;Load the FAT
|
||||
mov ax, [.sectorsperfat]
|
||||
;Load
|
||||
mov ah, 0x2
|
||||
int 0x13
|
||||
|
||||
;Load the file
|
||||
|
||||
;Load a cluster
|
||||
.loadcluster:
|
||||
;Set the source
|
||||
pop cx
|
||||
pop bx
|
||||
mov ax, word [.cluster]
|
||||
sub ax, 0x2
|
||||
mul byte [clustersize]
|
||||
add ax, [datastart]
|
||||
mul byte [.clustersize]
|
||||
add ax, bx
|
||||
add ax, cx
|
||||
push bx
|
||||
push cx
|
||||
call .calcsource
|
||||
;Set the destination
|
||||
mov bx, word [.pointer]
|
||||
;Set the size
|
||||
mov ch, 0x0
|
||||
mov cl, byte [clustersize]
|
||||
;Store the loop counter in the stack
|
||||
.loadsector:
|
||||
push cx
|
||||
;Set the source
|
||||
call .calcsource
|
||||
;Set the size
|
||||
push ax
|
||||
mov al, 0x1
|
||||
;Load a sector
|
||||
;mov al, 0x1
|
||||
mov al, [.clustersize]
|
||||
;Load
|
||||
mov ah, 0x2
|
||||
int 0x13
|
||||
pop ax
|
||||
;Set the next sector
|
||||
add ax, 0x1
|
||||
add bx, word [sectorsize]
|
||||
;Load the loop counter from the stack
|
||||
pop cx
|
||||
;Load the next sector
|
||||
loop .loadsector
|
||||
|
||||
;Calculate the next cluster
|
||||
;Check if the cluster is even or odd
|
||||
mov ax, [.cluster]
|
||||
mov dx, 0x0
|
||||
mov bx, 0x3
|
||||
|
|
@ -319,64 +172,71 @@ mov bx, 0x2
|
|||
div bx
|
||||
mov si, buffer
|
||||
add si, ax
|
||||
mov ax, word [si]
|
||||
mov ax, word [ds:si]
|
||||
or dx, dx
|
||||
jz .even
|
||||
;If the cluster is odd shift out the first four bits
|
||||
times 0x4 shr ax, 0x1
|
||||
shr ax, 1
|
||||
shr ax, 1
|
||||
shr ax, 1
|
||||
shr ax, 1
|
||||
jmp .contcalc
|
||||
;If the cluster is even mask out the final four bits
|
||||
.even:
|
||||
and ax, 0xfff
|
||||
.contcalc:
|
||||
;Check for the file end
|
||||
cmp ax, 0xff8
|
||||
jge .success
|
||||
;Store the address of the next cluster
|
||||
mov word [.cluster], ax
|
||||
;Set the destination of the next cluster
|
||||
mov ax, [sectorsize]
|
||||
mul word [clustersize]
|
||||
cmp ax, 0xff8
|
||||
jge .clearcarry
|
||||
mov ax, [.sectorsize]
|
||||
mul word [.clustersize]
|
||||
add word [.pointer], ax
|
||||
;Load the next cluster
|
||||
jmp .loadcluster
|
||||
|
||||
;Set AL to 0x0 and load the file size to CX if the load was succesful
|
||||
.success:
|
||||
mov al, 0x0
|
||||
mov cx, [.size]
|
||||
;Clear the carry flag if the load was succesful
|
||||
.clearcarry:
|
||||
clc
|
||||
|
||||
;Clear the stack
|
||||
.clearstack:
|
||||
pop cx
|
||||
pop bx
|
||||
|
||||
.done:
|
||||
|
||||
;Load DI, SI, DX, and BX from the stack
|
||||
;Load the initial registers from the stack
|
||||
pop di
|
||||
pop si
|
||||
pop dx
|
||||
pop cx
|
||||
pop bx
|
||||
pop ax
|
||||
|
||||
;Set AH to its initial value
|
||||
mov ah, 0x0
|
||||
|
||||
;Return
|
||||
;Set AL to 0x1 if there was an error and to 0x0 otherwise and return
|
||||
jc .setal
|
||||
mov al, 0x0
|
||||
iret
|
||||
.setal:
|
||||
mov al, 0x1
|
||||
iret
|
||||
|
||||
;Data
|
||||
.file times 0xb db 0x20
|
||||
.size dw 0x0
|
||||
.cluster dw 0x0
|
||||
.pointer dw 0x0
|
||||
.driverrormsg db "Drive not found", 0x0
|
||||
.diskerrormsg db "Unable to read disk", 0x0
|
||||
.filerrormsg db "File or command not found", 0x0
|
||||
.sizerrormsg db "Not enough memory", 0x0
|
||||
.file times 0xb db 0x20
|
||||
.errormsg db "File not found", 0x0
|
||||
.cluster dw 0x0
|
||||
.pointer dw 0x0
|
||||
|
||||
;***
|
||||
;These are temporary until i write something to load them from the disk itself
|
||||
.bootdrive db 0x0
|
||||
.sectorsize dw 0x200 ;bytes
|
||||
.clustersize db 0x2 ;sectors
|
||||
.bootsectors dw 0x1
|
||||
.fats db 0x2
|
||||
.rootentries dw 0x70
|
||||
.sectorsperfat dw 0x2
|
||||
.sectorspertrack dw 0x9
|
||||
.sides dw 0x2
|
||||
|
||||
;Check the file name and convert to upper case
|
||||
.checkconv:
|
||||
|
||||
;Check for the string end, length limit, and invalid characters
|
||||
;Check for the string end
|
||||
cmp al, 0x0
|
||||
je .load
|
||||
|
|
@ -408,8 +268,6 @@ jmp .error
|
|||
.contcheck3:
|
||||
cmp al, 0x7c
|
||||
je .error
|
||||
|
||||
;Check for lower case and convert it to upper case
|
||||
;Check for lower case
|
||||
cmp al, 0x61
|
||||
jl .storech
|
||||
|
|
@ -417,50 +275,30 @@ cmp al, 0x7a
|
|||
jg .storech
|
||||
;Convert lower to upper case
|
||||
sub al, 0x20
|
||||
|
||||
;Store the character
|
||||
.storech:
|
||||
;Store the character
|
||||
stosb
|
||||
|
||||
;Decrease the counter
|
||||
;Increase the counter
|
||||
dec bl
|
||||
|
||||
;Return
|
||||
ret
|
||||
|
||||
;***
|
||||
|
||||
;Calculate the source arguments for loading data from the disk
|
||||
.calcsource:
|
||||
|
||||
;Store AX and BX in the stack
|
||||
push ax
|
||||
push bx
|
||||
|
||||
;Calculate the cylinder, head, and sector
|
||||
;Store the logical sector in BX
|
||||
mov bx, ax
|
||||
;Calculate the sector
|
||||
mov dx, 0x0
|
||||
div word [sectorspertrack]
|
||||
div word [.sectorspertrack]
|
||||
add dl, 0x1
|
||||
mov cl, dl
|
||||
;Load the logical sector from BX
|
||||
mov ax, bx
|
||||
;Calculate the head and cylinder
|
||||
mov dx, 0x0
|
||||
div word [sectorspertrack]
|
||||
div word [.sectorspertrack]
|
||||
mov dx, 0x0
|
||||
div word [heads]
|
||||
mov dh, dl ;Head
|
||||
mov ch, al ;Cylinder
|
||||
|
||||
;Load the drive number
|
||||
mov dl, byte [drive]
|
||||
|
||||
;Load BX and AX from the stack
|
||||
div word [.sides]
|
||||
mov dh, dl
|
||||
mov ch, al
|
||||
pop bx
|
||||
pop ax
|
||||
|
||||
;Return
|
||||
mov dl, byte [.bootdrive]
|
||||
ret
|
||||
|
|
|
|||
101
src/PRINT.ASM
101
src/PRINT.ASM
|
|
@ -1,101 +0,0 @@
|
|||
cpu 8086
|
||||
org 0x3000
|
||||
|
||||
;Load a file and print it
|
||||
|
||||
;Set the stack
|
||||
cli
|
||||
mov sp, stack + 0x100
|
||||
sti
|
||||
|
||||
;Check for an empty tail
|
||||
;Check
|
||||
cmp byte [si], 0x0
|
||||
jne extract
|
||||
;Print an error message and abort if the tail is empty
|
||||
mov si, errormsg
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
je done
|
||||
|
||||
;Find the end of the filename and add a null if needed
|
||||
;Set DI at the tail
|
||||
extract:
|
||||
mov di, si
|
||||
findend:
|
||||
;Check for the string end
|
||||
cmp byte [di], 0x0
|
||||
je load
|
||||
;Check for a space
|
||||
cmp byte [di], 0x20
|
||||
je addnull
|
||||
inc di
|
||||
jmp findend
|
||||
;Add a null
|
||||
addnull:
|
||||
mov al, 0x0
|
||||
stosb
|
||||
|
||||
;Load the file
|
||||
;Load
|
||||
load:
|
||||
mov bx, stack + 0x100
|
||||
mov ah, 0x2
|
||||
int 0x22
|
||||
;Check for errors
|
||||
cmp al, 0x0
|
||||
jne done
|
||||
|
||||
;Print the file
|
||||
;Setup
|
||||
mov bh, 0x0
|
||||
mov bl, 0x18
|
||||
mov dl, 0x50
|
||||
mov si, stack + 0x100
|
||||
;Decrease the character counter
|
||||
print:
|
||||
dec dl
|
||||
;Load the current character
|
||||
lodsb
|
||||
;Print the character
|
||||
mov ah, 0xe
|
||||
int 0x10
|
||||
;Check for a hard line end
|
||||
cmp al, 0xa
|
||||
je linecount
|
||||
;Check for a soft line end
|
||||
cmp dl, 0x0
|
||||
je linecount
|
||||
;Check paging
|
||||
contprint:
|
||||
cmp bl, 0x0
|
||||
jz page
|
||||
;Repeat for the next character
|
||||
loop print
|
||||
jmp done
|
||||
;Decrease the line counter and reset the character one
|
||||
linecount:
|
||||
dec bl
|
||||
mov dl, 0x50
|
||||
jmp contprint
|
||||
;Page
|
||||
page:
|
||||
push ax
|
||||
mov ah, 0x0
|
||||
int 0x16
|
||||
cmp al, 0x1b
|
||||
je done
|
||||
pop ax
|
||||
mov bl, 0x18
|
||||
mov dl, 0x50
|
||||
loop print
|
||||
|
||||
;Return to the system
|
||||
done:
|
||||
int 0x20
|
||||
|
||||
;Data
|
||||
errormsg db "File not found", 0x0
|
||||
|
||||
;Stack
|
||||
stack:
|
||||
|
|
@ -1,4 +1,5 @@
|
|||
;Print a string ending in a null from SI followed by a CRLF.
|
||||
|
||||
println:
|
||||
|
||||
;Print the string
|
||||
|
|
@ -8,5 +9,4 @@ int 0x21
|
|||
;Print a CRLF
|
||||
call printcrlf
|
||||
|
||||
;Return
|
||||
iret
|
||||
|
|
|
|||
|
|
@ -1,13 +1,14 @@
|
|||
;Print a string ending in a null from SI.
|
||||
|
||||
printstr:
|
||||
|
||||
;Store AX and SI in the stack
|
||||
;Store the initial registers in the stack
|
||||
push ax
|
||||
push si
|
||||
|
||||
;Print the string
|
||||
;Load the current character
|
||||
.loop:
|
||||
;Load the current character
|
||||
lodsb
|
||||
;Check for the string end
|
||||
cmp al, 0x0
|
||||
|
|
@ -15,13 +16,13 @@ je .done
|
|||
;Print the character
|
||||
mov ah, 0xe
|
||||
int 0x10
|
||||
;Print the next character
|
||||
;Repeat for the next character
|
||||
jmp .loop
|
||||
|
||||
;Load the initial registers from the stack
|
||||
.done:
|
||||
|
||||
;Load the initial registers from the stack
|
||||
pop si
|
||||
pop ax
|
||||
|
||||
;Return
|
||||
iret
|
||||
|
|
|
|||
|
|
@ -1,5 +1,5 @@
|
|||
;Read a string ending in a null of at most AL characters to DI until a
|
||||
;return and print a CRLF.
|
||||
;Read a string ending in null of at most AL characters to DI until a return and print a CRLF.
|
||||
|
||||
readln:
|
||||
|
||||
;Read the string
|
||||
|
|
@ -9,5 +9,4 @@ int 0x21
|
|||
;Print a CRLF
|
||||
call printcrlf
|
||||
|
||||
;Return
|
||||
iret
|
||||
|
|
|
|||
|
|
@ -1,8 +1,8 @@
|
|||
;Read a string ending in a null of at most AL characters to DI until a
|
||||
;return.
|
||||
;Read a string ending in a null of at most AL characters to DI until a return.
|
||||
|
||||
readstr:
|
||||
|
||||
;Store AX, BX, CX, DX, and DI in the stack
|
||||
;Store the initial registers in the stack
|
||||
push ax
|
||||
push bx
|
||||
push cx
|
||||
|
|
@ -20,16 +20,12 @@ rep stosb
|
|||
pop ax
|
||||
push ax
|
||||
sub di, ax
|
||||
;Store the last column number
|
||||
mov ah, 0xf
|
||||
int 0x10
|
||||
dec ah
|
||||
mov [.lastcolumn], ah
|
||||
;Set the cursor pointer in BL and clear BH
|
||||
;Initialise the cursor pointer in BL and clear BH
|
||||
mov bx, 0x1
|
||||
|
||||
;Read a keypress
|
||||
.loop:
|
||||
|
||||
;Read a keypress
|
||||
mov ah, 0x0
|
||||
int 0x16
|
||||
|
||||
|
|
@ -59,9 +55,9 @@ je .loop
|
|||
|
||||
;Store and print a character
|
||||
.character:
|
||||
;Store
|
||||
;Store the character
|
||||
stosb
|
||||
;Print
|
||||
;Print the character
|
||||
mov ah, 0xe
|
||||
int 0x10
|
||||
;Move the cursor pointer
|
||||
|
|
@ -91,21 +87,23 @@ dec di
|
|||
dec bl
|
||||
jmp .loop
|
||||
|
||||
;Check for and remove trailing spaces
|
||||
;Go to the end of the input
|
||||
;Finish reading the string
|
||||
.return:
|
||||
|
||||
;Find and remove trailing spaces
|
||||
;Go to the end of the input
|
||||
pop ax
|
||||
mov bh, 0x0
|
||||
sub ax, bx
|
||||
push di
|
||||
add di, ax
|
||||
;Check for trailing spaces
|
||||
.findtrailing:
|
||||
;Check for a trailing space
|
||||
cmp byte [di], 0x20
|
||||
je .deltrailing
|
||||
jmp .end
|
||||
;Remove trailing spaces
|
||||
.deltrailing:
|
||||
;Delete a trailing space
|
||||
mov al, 0x0
|
||||
stosb
|
||||
sub di, 0x2
|
||||
|
|
@ -124,102 +122,83 @@ inc di
|
|||
inc bl
|
||||
jmp .findend
|
||||
|
||||
;Load DI, DX, CX, BX, and AX from the stack
|
||||
.done:
|
||||
|
||||
;Load the initial registers from the stack
|
||||
pop di
|
||||
pop dx
|
||||
pop cx
|
||||
pop bx
|
||||
pop ax
|
||||
|
||||
;Return
|
||||
iret
|
||||
|
||||
;Data
|
||||
.lastcolumn db 0x0
|
||||
|
||||
;***
|
||||
|
||||
;Move the cursor forward
|
||||
.nextchar:
|
||||
|
||||
;Move forward within a line
|
||||
.nextchar:
|
||||
;Get the cursor position
|
||||
mov ah, 0x3
|
||||
int 0x10
|
||||
|
||||
;Check for the end of the line
|
||||
cmp dl, [.lastcolumn]
|
||||
cmp dl, 0x4f
|
||||
je .nextln
|
||||
|
||||
;Move the cursor forward within a line
|
||||
;Move
|
||||
inc dl
|
||||
mov ah, 0x2
|
||||
int 0x10
|
||||
|
||||
;Return
|
||||
ret
|
||||
|
||||
;Move the cursor to the beginning of the next line
|
||||
;Check if the current line is the last on screen
|
||||
;Move to the beginning of the next line
|
||||
.nextln:
|
||||
;Check if the current line is the last on screen
|
||||
cmp dh, 0x18
|
||||
je .scroll
|
||||
;Move the cursor
|
||||
;Move
|
||||
mov ah, 0x2
|
||||
inc dh
|
||||
mov dl, 0x0
|
||||
int 0x10
|
||||
|
||||
;Return
|
||||
ret
|
||||
|
||||
;Scroll the screen up by one line
|
||||
.scroll:
|
||||
;Scroll
|
||||
mov ah, 0x6
|
||||
mov al, 0x1
|
||||
mov bh, 0x7
|
||||
mov ch, 0x0
|
||||
mov cl, 0x0
|
||||
mov dh, 0x18
|
||||
mov dl, [.lastcolumn]
|
||||
mov dl, 0x4f
|
||||
int 0x10
|
||||
|
||||
;Move to the beginning of the new line
|
||||
mov ah, 0x2
|
||||
mov bh, 0x0
|
||||
mov dl, 0x0
|
||||
int 0x10
|
||||
|
||||
;Return
|
||||
ret
|
||||
|
||||
;***
|
||||
|
||||
;Move the cursor backward
|
||||
.prevchar:
|
||||
|
||||
;Move backward within a line
|
||||
.prevchar:
|
||||
;Get the cursor position
|
||||
mov ah, 0x3
|
||||
int 0x10
|
||||
|
||||
;Check for the beginning of the line
|
||||
cmp dl, 0x0
|
||||
je .prevln
|
||||
|
||||
;Move the cursor backward within a line
|
||||
;Move
|
||||
dec dl
|
||||
mov ah, 0x2
|
||||
int 0x10
|
||||
|
||||
;Return
|
||||
ret
|
||||
|
||||
;Move the cursor to the end of the previous line
|
||||
;Move to the end of the previous line
|
||||
.prevln:
|
||||
mov ah, 0x2
|
||||
dec dh
|
||||
mov dl, [.lastcolumn]
|
||||
mov dl, 0x4f
|
||||
int 0x10
|
||||
|
||||
;Return
|
||||
ret
|
||||
|
|
|
|||
233
src/SYSTEM.ASM
233
src/SYSTEM.ASM
|
|
@ -1,7 +1,6 @@
|
|||
cpu 8086
|
||||
org 0x500
|
||||
CPU 8086
|
||||
ORG 0x500
|
||||
|
||||
;Jump to the code
|
||||
jmp start
|
||||
|
||||
;Interrupt handler
|
||||
|
|
@ -21,21 +20,22 @@ je readln
|
|||
iret
|
||||
;Disk operations
|
||||
int0x22:
|
||||
cmp ah, 0x2
|
||||
cmp ah, 0x0
|
||||
je loadf
|
||||
;To do: savef
|
||||
iret
|
||||
|
||||
;System call includes
|
||||
;System calls
|
||||
%include "PRINTSTR.INC"
|
||||
%include "READSTR.INC"
|
||||
%include "PRINTLN.INC"
|
||||
%include "READLN.INC"
|
||||
%include "LOADF.INC"
|
||||
|
||||
start:
|
||||
|
||||
;Set up the interrupt vectors
|
||||
;Interrupt 0x20 offset
|
||||
start:
|
||||
mov ax, int0x20
|
||||
mov [0x80], ax
|
||||
;Interrupt 0x21 offset
|
||||
|
|
@ -50,11 +50,6 @@ mov [0x82], ax
|
|||
mov [0x86], ax
|
||||
mov [0x8a], ax
|
||||
|
||||
;Store the boot drive number as the current drive and set the current
|
||||
;drive letter
|
||||
mov [curdrive], dl
|
||||
call setcurdriveletter
|
||||
|
||||
;Print a welcome message
|
||||
mov si, welcomemsg
|
||||
mov ah, 0x2
|
||||
|
|
@ -68,226 +63,62 @@ mov sp, 0x0
|
|||
sti
|
||||
|
||||
;Prompt for and read a command
|
||||
;Print the current drive letter
|
||||
mov si, curdriveletter
|
||||
mov ah, 0x0
|
||||
int 0x21
|
||||
;Print a prompt
|
||||
mov si, prompt
|
||||
mov ah, 0x0
|
||||
int 0x21
|
||||
;Read
|
||||
mov di, input
|
||||
mov al, 0x4c
|
||||
mov al, 0x4e
|
||||
mov ah, 0x3
|
||||
int 0x21
|
||||
|
||||
;Load an execute the program
|
||||
;Check for an empty command
|
||||
cmp byte [input], 0x0
|
||||
jz shell
|
||||
|
||||
;Set SI at the command
|
||||
;Set SI at input
|
||||
;Load
|
||||
mov bx, 0x2000
|
||||
mov si, input
|
||||
;Ignore leading spaces
|
||||
call ignoreleading
|
||||
|
||||
;Check for a current drive change command
|
||||
cmp byte [si + 0x1], ":"
|
||||
jne extract
|
||||
cmp byte [si + 0x2], 0x0
|
||||
je changecurdrive
|
||||
cmp byte [si + 0x2], 0x20
|
||||
je changecurdrive
|
||||
|
||||
;Extract the specification of the program file
|
||||
extract:
|
||||
;Set DI at program
|
||||
mov di, program
|
||||
;Initialise program with spaces
|
||||
mov cx, 0xe
|
||||
mov al, 0x20
|
||||
rep stosb
|
||||
sub di, 0xe
|
||||
;Set the length counter
|
||||
mov bl, 0xa
|
||||
;Load a character
|
||||
specloop:
|
||||
lodsb
|
||||
;Check for the string end
|
||||
cmp al, 0x0
|
||||
je addext
|
||||
;Check for a space
|
||||
cmp al, 0x20
|
||||
je addext
|
||||
;Check for the length limit
|
||||
cmp bl, 0x0
|
||||
je cmderror
|
||||
;Store the character
|
||||
stosb
|
||||
;Decrease the counter
|
||||
dec bl
|
||||
;Extract the next character
|
||||
jmp specloop
|
||||
;Store the start of the command tail in the stack
|
||||
addext:
|
||||
push si
|
||||
;Add extension to the specification
|
||||
mov si, extension
|
||||
mov cx, 0x5
|
||||
rep movsb
|
||||
|
||||
;Load and execute the program
|
||||
;Load the program
|
||||
mov bx, 0x3000
|
||||
mov si, program
|
||||
mov ah, 0x2
|
||||
mov ah, 0x0
|
||||
int 0x22
|
||||
;Check for errors
|
||||
cmp al, 0x0
|
||||
jne shell
|
||||
;Pass the current drive and command tail to the program
|
||||
mov dl, [curdrive]
|
||||
pop si
|
||||
call ignoreleading
|
||||
;Execute the program
|
||||
jmp 0x3000
|
||||
cmp al, 0x1
|
||||
je error
|
||||
;Execute
|
||||
jmp 0x2000
|
||||
|
||||
;Print a command error message and return to the shell
|
||||
cmderror:
|
||||
mov si, cmderrormsg
|
||||
;Print an error message and return to the shell
|
||||
error:
|
||||
mov bh, 0x0
|
||||
mov ah, 0x3
|
||||
int 0x10
|
||||
dec dh
|
||||
mov ah, 0x2
|
||||
int 0x10
|
||||
mov si, errormsg
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
jmp shell
|
||||
|
||||
;Change the current drive
|
||||
;Get the BIOS equipment list
|
||||
changecurdrive:
|
||||
int 0x11
|
||||
;Get the number of floppy drives
|
||||
times 0x6 shr ax, 0x1
|
||||
and ax, 0x3
|
||||
inc ax
|
||||
;Set the loop and drive letter counters and the drive letter and number
|
||||
mov cx, ax
|
||||
mov di, driveletters
|
||||
mov al, [si]
|
||||
mov dl, 0x0
|
||||
;Check which drive to change to
|
||||
checkdrive:
|
||||
cmp al, [di]
|
||||
je contchdrive
|
||||
inc di
|
||||
cmp al, [di]
|
||||
je contchdrive
|
||||
inc di
|
||||
inc dl
|
||||
loop checkdrive
|
||||
;Print a drive error message and return to the shell
|
||||
mov si, driverrormsg
|
||||
mov ah, 0x2
|
||||
int 0x21
|
||||
jmp shell
|
||||
;Change the drive
|
||||
contchdrive:
|
||||
mov [curdrive], dl
|
||||
call setcurdriveletter
|
||||
jmp shell
|
||||
|
||||
;Welcome message
|
||||
;Data
|
||||
welcomemsg db 0xd, 0xa, "Welcome to EttinOS!", 0xd, 0xa, 0x0
|
||||
|
||||
;Drive stuff
|
||||
curdrive db 0x0
|
||||
driveletters db "AaBbCcDd"
|
||||
|
||||
;Shell
|
||||
curdriveletter db "?:", 0x0
|
||||
prompt db "> ", 0x0
|
||||
input times 0x4c db 0x0
|
||||
program times 0xf db 0x0
|
||||
extension db ".BIN", 0x0
|
||||
cmderrormsg db "File or command not found", 0x0
|
||||
driverrormsg db "Drive not found", 0x0
|
||||
|
||||
;Disk parameters
|
||||
drive db 0x0
|
||||
sectorsize dw 0x0 ;bytes
|
||||
clustersize db 0x0 ;sectors
|
||||
reservedsectors dw 0x0
|
||||
fats db 0x0
|
||||
rootentries dw 0x0
|
||||
sectorsperfat dw 0x0
|
||||
sectorspertrack dw 0x0
|
||||
heads dw 0x0
|
||||
rootstart dw 0x0
|
||||
rootsectors dw 0x0
|
||||
datastart dw 0x0
|
||||
|
||||
;***
|
||||
|
||||
;Set the drive letter
|
||||
setcurdriveletter:
|
||||
|
||||
;Set the drive number and letter counters
|
||||
mov dh, 0x0
|
||||
mov si, driveletters
|
||||
|
||||
;Check the drive number
|
||||
.checkdrive:
|
||||
cmp dl, dh
|
||||
je .set
|
||||
add si, 0x2
|
||||
inc dh
|
||||
jmp .checkdrive
|
||||
|
||||
;Set the drive letter
|
||||
.set:
|
||||
mov al, [si]
|
||||
mov byte [curdriveletter], al
|
||||
|
||||
;Return
|
||||
ret
|
||||
|
||||
;***
|
||||
|
||||
;Ignore leading spaces in the command and its tail
|
||||
ignoreleading:
|
||||
|
||||
;Check for a space
|
||||
lodsb
|
||||
cmp al, 0x20
|
||||
je ignoreleading
|
||||
|
||||
;Set SI to the first non-space character
|
||||
dec si
|
||||
|
||||
;Return
|
||||
ret
|
||||
|
||||
;***
|
||||
prompt db "> ", 0x0
|
||||
errormsg db "Unknown command", 0x0
|
||||
input times 0x4e db 0x0
|
||||
crlf db 0xd, 0xa, 0x0
|
||||
|
||||
;Print a CRLF
|
||||
printcrlf:
|
||||
|
||||
;Store SI in the stack
|
||||
;Store the initial registers in the stack
|
||||
push si
|
||||
|
||||
;Print the CRLF
|
||||
mov si, .crlf
|
||||
mov si, crlf
|
||||
mov ah, 0x0
|
||||
int 0x21
|
||||
|
||||
;Load SI from the stack
|
||||
;Load the initial registers from the stack
|
||||
pop si
|
||||
|
||||
;Return
|
||||
ret
|
||||
|
||||
;Data
|
||||
.crlf db 0xd, 0xa, 0x0
|
||||
|
||||
;***
|
||||
|
||||
;File system buffer
|
||||
buffer:
|
||||
|
|
|
|||
Loading…
Reference in New Issue