am trying to port a tasm program to nasm but I am getting following syntax errors:
D:\NASMPR~1>nasm -f bin -o boot.bin bootsec.asm
bootsec.asm:96: error: comma or end of line expected
bootsec.asm:103: error: parser: instruction expected
bootsec.asm:110: error: comma or end of line expected
bootsec.asm:145: error: symbol `PrintMessage' redefined
bootsec.asm:145: error: parser: instruction expected
bootsec.asm:149: error: parser: instruction expected
bootsec.asm:155: error: symbol `GetKey' redefined
bootsec.asm:155: error: parser: instruction expected
bootsec.asm:159: error: parser: instruction expected
bootsec.asm:178: error: symbol `GiveControlToOS' redefined
bootsec.asm:178: error: parser: instruction expected
bootsec.asm:182: error: parser: instruction expected
bootsec.asm:191: error: label or instruction expected at start of line
bootsec.asm:192: error: label or instruction expected at start of line
bootsec.asm:197: error: symbol `ClearScreen' redefined
bootsec.asm:197: error: parser: instruction expected
bootsec.asm:201: error: parser: instruction expected
bootsec.asm:209: error: symbol `PrintPlaceMarker' redefined
bootsec.asm:209: error: parser: instruction expected
bootsec.asm:213: error: parser: instruction expected
bootsec.asm:223: error: comma or end of line expected
bootsec.asm:224: error: comma or end of line expected
bootsec.asm:232: error: symbol `SetNewDisketteParameterTable' redefined
bootsec.asm:232: error: parser: instruction expected
bootsec.asm:236: error: parser: instruction expected
bootsec.asm:269: error: symbol `DownloadOS' redefined
bootsec.asm:269: error: parser: instruction expected
bootsec.asm:273: error: parser: instruction expected
bootsec.asm:320: error: symbol `ReadSector' redefined
bootsec.asm:320: error: parser: instruction expected
D:\NASMPR~1>
My program is given below and I am working on windows XP:
;nasm -f bin -o boot.bin boot07.asm
;nasm -f bin -o writeit.com writeit.asm
ORG 7c00h ;Because BIOS loades the OS at
; address 0:7C00h so ORG 7C00h
; makes that the refrence to date
; are with the right offset (7c00h).
; CS = 0 / IP = 7C00h // SS = ? / SP = ?
; You are now at address 7c00.
jmp start ;Here we start the, BIOS gave us now the control.
;///////////////////////////////////////////
;//Here goes all the data of the program.
;///////////////////////////////////////////
xCursor db 0
yCursor db 0
nSector db 0
nTrack db 0
nSide db 0
nDrive db 0
nTrays db 0
;
szReady db 'Are You Ready to start Loading the OS...',0
szErrorReadingDrive db 'Error Reading Drive, Press any Key to reboot...',0
;//Done Reading a track.
szPlaceMarker db '~~~~',0
szDone db 'Done',0
pOS dw 7E00h
;//Points to were to download the Operating System.
;//Disk Paremeter Table.
StepRateAndHeadUnloadTime db 0DFh
HeadLoadTimeAndDMAModeFlag db 2h
DelayForMotorTurnOff db 25h
;// (1 = 256) //(2 = 512 bytes)
BytesPerSector db 2h
;// 18 sectors in a track.
SectorsPerTrack db 18
IntersectorGapLength db 1Bh
DataLength db 0FFh
IntersectorGapLengthDuringFormat db 54h
FormatByteValue db 0F6h
HeadSettlingTime db 0Fh
DelayUntilMotorAtNormalSpeed db 8h
DisketteSectorAddress_as_LBA_OfTheDataArea db 0
CylinderNumberToReadFrom db 0
SectorNumberToReadFrom db 0
DisketteSectorAddress_as_LBA_OfTheRootDirectory db 0
;/////////////////////////////////
;//Here the program starts.
;/////////////////////////////////
start:
CLI ;Clear Interupt Flag so while setting
;up the stack any intrupt would not be fired.
mov AX,7B0h ;lets have the stack start at 7c00h-256 = 7B00h
mov SS,ax ;SS:SP = 7B0h:256 = 7B00h:256
mov SP,256 ;Lets make the stack 256 bytes.
Mov ax,CS ;Set the data segment = CS = 0
mov DS,ax
XOR AX,AX ;Makes AX=0.
MOV ES,AX ;Make ES=0
STI ;Set Back the Interupt Flag after
;we finished setting a stack fram.
Call ClearScreen ;ClearScreen()
LEA AX,szReady ;Get Address of szReady.
CALL PrintMessage ;Call PrintfMessage()
CALL GetKey ;Call GetKey()
CALL SetNewDisketteParameterTable
;SetNewDisketteParameterTable()
CALL DownloadOS
CALL GetKey ;Call GetKey()
CALL FAR PTR GiveControlToOS ;Give Control To OS.
ret
;/////////////////////////////////////
;//Prints a message to the screen.
;/////////////////////////////////////
PrintMessage PROC
mov DI,AX ;AX holds the address of the string to Display.
Mov xCursor,1 ;Column.
ContinuPrinting:
cmp byte ptr [DI],0 ;Did we get to the End of String.
JE EndPrintingMessage ;if you gat to the end of the string return.
mov AH,2 ;Move Cursor
mov DH,yCursor ;row.
mov DL,xCursor ;column.
mov BH,0 ;page number.
INT 10h
INC xCursor
mov AH,0Ah ;Display Character Function.
mov AL,[DI] ;character to display.
mov BH,0 ;page number.
mov CX,1 ;number of times to write character
INT 10h
INC DI ;Go to next character.
JMP ContinuPrinting ;go to Print Next Character.
EndPrintingMessage:
Inc yCursor ;So Next time the message would
;be printed in the second line.
cmp yCursor,25
JNE dontMoveCorsurToBegin
Mov yCursor,0
dontMoveCorsurToBegin:
ret
PrintMessage EndP
;//////////////////////////////////////
;//Watis for the user to press a key.
;//////////////////////////////////////
GetKey PROC
mov ah,0
int 16h ;Wait for a key press.
Ret
GetKey EndP
;///////////////////////////////////////////
;//Gives Control To Second Part Loader.
;///////////////////////////////////////////
GiveControlToOS PROC
LEA AX,szDone
Call PrintMessage
CALL GetKey
db 0e9h ;Far JMP op code.
dw 512 ;JMP 512 bytes ahead.
; POP AX ;//Another why to make
;the CPU jump to a new place.
; POP AX
; Push 7E0h ;Push New CS address.
; Push 0 ;Push New IP address.
;The address that comes out is 7E00:0000.
;(512 bytes Higher from were BIOS Put us.)
; ret
GiveControlToOS EndP
;///////////////////////////////////
;//Clear Screen.
;///////////////////////////////////
ClearScreen PROC
mov ax,0600h ;//Scroll All Screen UP to Clear Screen.
mov bh,07
mov cx,0
mov dx,184fh
int 10h
Mov xCursor,0 ;//Set Corsur Position So next
//write would start in
//the beginning of screen.
Mov yCursor,0
Ret
ClearScreen EndP
;/////////////////////////////////
;//PrintPlaceMarker.
;/////////////////////////////////
PrintPlaceMarker PROC
LEA AX,szPlaceMarker
CALL PrintMessage ;Call PrintfMessage()
CALL GetKey ;Call GetKey()
ret
PrintPlaceMarker EndP
;/////////////////////////////////////////
;//Set New Disk Parameter Table
;/////////////////////////////////////////
SetNewDisketteParameterTable PROC
LEA DX,StepRateAndHeadUnloadTime
;//Get the address of the Disk Parameters Block.
;//Int 1E (that is in address 0:78h)
;//holds the address of the disk parametrs
;//block, so now change it to
;//our parametr black.
;//DX holds the address of our Parameters block.
MOV WORD PTR CS:[0078h],DX
MOV WORD PTR CS:[007Ah],0000
;Reset Drive To Update the DisketteParameterTable.
MOV AH,0
INT 13H
ret
SetNewDisketteParameterTable EndP
;///////////////////////////////////
;//DownloadOS
;///////////////////////////////////
DownloadOS PROC
mov nDrive,0
mov nSide,0
mov nTrack,0
mov nSector,1
ContinueDownload:
INC nSector ;Read Next Sector.
cmp nSector,19 ;Did we get to end of track.
JNE StayInTrack
CALL PrintPlaceMarker ;Print now '~~~~' so the user would
;now that we finished reding a track
INC nTrack ;If we gat to end of track Move to next track.
mov nSector,1 ;And Read Next Sector.
CMP nTrack,5 ;Read 5 Tracks (Modify this value
;to how much Tracks you want to read).
JE EndDownloadingOS
StayInTrack:
;ReadSector();
Call ReadSector
JMP ContinueDownload
;If diden't yet finish Loading OS.
EndDownloadingOS:
ret
DownloadOS EndP
;////////////////////////////////////////
;//Read Sector.
;////////////////////////////////////////
ReadSector PROC
mov nTrays,0
TryAgain:
mov AH,2 ;//Read Function.
mov AL,1 ;//1 Sector.
mov CH,nTrack
mov CL,nSector ;//Remember: Sectors start with 1, not 0.
mov DH,nSide
mov DL,nDrive
Mov BX,pOS ;//ES:BX points to the address
;to were to store the sector.
INT 13h
CMP AH,0 ;Int 13 return Code is in AH.
JE EndReadSector ;if 'Sucsess' (AH = 0) End function.
mov AH,0 ;Else Reset Drive . And Try Again...
INT 13h
cmp nTrays,3 ;Chack if you tryed reading
;more then 3 times.
JE DisplayError ; if tryed 3 Times Display Error.
INC nTrays
jmp TryAgain ;Try Reading again.
DisplayError:
LEA AX,szErrorReadingDrive
Call PrintMessage
Call GetKey
mov AH,0 ;Reboot Computer.
INT 19h
EndReadSector:
;ADD WORD PTR pOS,512 ;//Move the pointer
;(ES:BX = ES:pOS = 0:pOS) 512 bytes.
;//Here you set the varible
;pOS (pOS points to were BIOS
;//Would load the Next Sector).
Ret
ReadSector EndP
;////////////////////////////////////
;//
;////////////////////////////////////
Can somebody plz help me with this? I would really appreciate it.
Zulfi.
