汇编源码系列之burnout

汇编源码系列之burnout2008-04-30这个都是过去DOS时代的汇编源码，虽然已经过去了，但是对于学习汇编还是有帮助的，汇编语言只是程序员一门基础语言，大多人掌握即可，不一定要深入研究.......
COMMENT *
 Demo （and semi-useful） program to read/set burnout device parameters.
 Usage: burnout [ticks] [C+-] [V+-] [H+-]
 Parameters can be separated by almost anything.
 With no parameters, program simply returns current status.
 Examples:
  burnout 5000        （sets time to 5000 ticks）
  burnout 5000H+       （time=5000, use hardware blanking）
  burnout 5000,h+       （ditto, separators don"t matter）
  burnout c+h-v+       （continuous clear, software, monitor video）
  burnout /C+ /H- /V+     （ditto）
  burnout           （return status only）
 Assembly/link:
  masm burnout;
  link burnout; （ignore NO STACK warning message）
  exe2bin burnout burnout.com
 By CJDunford 20-Mar-1985
   Compuserve 76703,2002
======================================================================
*
stdout equ 1              ; DOS output files
stderr equ 2
; ----- General equates
DOS     equ 21H           ; DOS interrupt
TERMINATE  equ 20H           ; Exit to DOS
PRINT    equ 09H           ; DOS "print" string to stdout
FOPEN    equ 3D02H          ; DOS file open, read/write
FREAD    equ 3FH           ; DOS file read
FWRITE   equ 40H           ; DOS file write
CR     equ 13           ; ASCII carriage return
LF     equ 10           ; ASCII line fine
code segment
assume cs:code,ds:code
org 80H                 ; Parm storage area in PSP
ParmLength label byte          ; Length of parms
org 81H
Parameters label byte          ; Start of parms
org 100H                ; Org for .COM
main proc far
    jmp start            ; Hate to execute data
DevName     db "BRNDEV",0      ; Burnout device name
handle     dw ？          ; Storage for handle
Flush      db "@"         ; Char to flush device I/O
Execute     db "#"         ; Char to execute device commands
NotInstalled  db "Burnout device is not installed",13,10
NotInstalledL  equ $ - NotInstalled
Status     db "Current status: "  ; Status message
StatInsert   db 40 dup （？）      ; brndev will store status here
; ----- Open the device
start:
    mov dx,offset DevName      ; DS:DX => device name
    mov ax,FOPEN
    int DOS
    jnc A1             ; Continue if no error
    mov bx,stderr          ; Message to stderr
    mov cx,NotInstalledL
    mov dx,offset NotInstalled
    mov ah,FWRITE
    int DOS
    jmp exit
; ----- Flush any pending I/O to/from the device
A1:
    mov handle,ax          ; Save device handle
    mov dx,offset Flush       ; Point to the "@"
    mov cx,1            ; Writing one byte
    mov bx,handle          ; Device handle
    mov ah,FWRITE          ; Write "@" to device
    int DOS
; ----- Send and execute parameters if present
    mov cl,ParmLength        ; Parm length to CL
    or cl,cl            ; Any parms present？
    jz A2              ; Skip if not
    xor ch,ch            ; CX = parm length
    mov dx,offset Parameters    ; DS:DX => parms
    mov bx,handle          ; BX = device handle
    mov ah,FWRITE          ; Write parms to device
    int DOS
    mov dx,offset Execute      ; Execute the parms
    mov cx,1            ; Writing one byte
    mov bx,handle          ; Device handle
    mov ah,FWRITE          ; Write "#" to device
    int DOS
; ----- Get and display device status
A2:
    mov dx,offset StatInsert    ; DS:DX => where to put status
    mov cx,0FFH           ; Ask for lots of data; DOS will ...
                    ; ... fetch only until CR found.
    mov bx,handle          ; Device handle
    mov ah,FREAD          ; Read device info
    int DOS
    mov cx,ax            ; CX = actual # bytes read
    mov di,offset StatInsert    ; Where the stat data is stored
    add di,cx            ; Add length of input read
    mov al,CR            ; Store a CR/LF/"$" at end
    cld
    stosb
    mov al,LF
    stosb
    mov al,"$"
    stosb
    mov dx,offset Status      ; Write status to stdout
    mov ah,PRINT
    int DOS
exit:
    int TERMINATE          ; Exit to DOS
main endp
code ends
end main