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汇编源码系列之clr

 2008-04-29 09:33:53 来源:WEB开发网   
核心提示:这个都是过去DOS时代的汇编源码,虽然已经过去了,汇编源码系列之clr,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

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.......

  PAGE  60,132
; CLR.ASM  05/29/84
; Subroutine called by a basic program to scroll a window.
;
;
DGROUP  GROUP  DATASEG
DATASEG SEGMENT PARA PUBLIC 'DATA'
FUNCT  DW  0    ;function 1=6,0=7
FG_COLR DW  0    ;forground color
BG_COLR DW  0    ;backround color
LINES  DW  0    ;number of lines to scroll or 0 for clear
ULROW  DW  0    ;upper left row
ULCOL  DW  0    ;upper left column
LRROW  DW  0    ;lower right row
LRCOL  DW  0    ;lower left column
ATTRIB  DB  0    ;temp hold for attribute byte
CALNU  DB  0    ;temp hold for call function 6 or 7
DATASEG ENDS
;
CSEG  SEGMENT 'CODE'
  ASSUME  CS:CSEG
  PUBLIC CLR
CLR  PROC  FAR
  PUSH  BP    ;BP unknown (don't care)
  MOV  BP,SP    ;set base for parm list
  PUSH  DS    ;DS -> basic work area
  PUSH  ES    ;ES -> basic work area
  MOV  AX,DATASEG  ;establish data addressability
  MOV  DS,AX    ;now DS -> my data
  ASSUME  DS:DATASEG
;
;
  MOV  SI,SS:[BP+6]  ;get addr of parameter
  MOV  AX,ES:[SI]  ;get value of parm
  MOV  FUNCT,AX
  MOV  SI,SS:[BP+8]  ;get addr of parameter
  MOV  AX,ES:[SI]  ;get value of parm
  MOV  BG_COLR,AX
  MOV  SI,SS:[BP+10]  ;get addr of parameter
  MOV  AX,ES:[SI]  ;get value of parm
  MOV  FG_COLR,AX
  MOV  SI,SS:[BP+12]  ;get addr of parameter
  MOV  AX,ES:[SI]  ;get value of parm
  MOV  LINES,AX
  MOV  SI,SS:[BP+14]  ;get addr of parameter
  MOV  AX,ES:[SI]  ;get value of parm
  MOV  ULROW,AX
  MOV  SI,SS:[BP+16]  ;get addr of parameter
  MOV  AX,ES:[SI]  ;get value of parm
  MOV  ULCOL,AX
  MOV  SI,SS:[BP+18]   ;get addr of parameter
  MOV  AX,ES:[SI]  ;get value of parm
  MOV  LRROW,AX
  MOV  SI,SS:[BP+20]   ;get addr of parameter
  MOV  AX,ES:[SI]  ;get value of parm
  MOV  LRCOL,AX
;
  MOV  AX,1
  SUB  LRROW,AX  ;convert 1-80 cols
  SUB  LRCOL,AX  ; and 1-25 rows into
  SUB  ULROW,AX  ; 0-79 cols and
  SUB  ULCOL,AX  ; 0-24 rows
;
; change forground & backround colors into single attribute byte
;
  MOV  BX,FG_COLR  ;move foreground color to bx
  MOV  AL,BL    ;move lower byte to al
  MOV  BX,BG_COLR  ;move backround color to bx
  MOV  AH,BL    ;move lower byte to ah
  CMP  AL,15    ;check for color > 15 ie blinking
  JG  BLNK    ;if > 15 then set blink bit
  AND  AL,15    ;set normal fg color
  JMP  N_BLNK    ;
BLNK:  OR  AL,128    ;set blink bit 7
  AND  AL,143    ;zero out bit 6,5,4 used for backround
N_BLNK: AND  AH,7    ;zero out bit 7,6,5,4,3 used for forground
  MOV  CL,4    ;4 bit shift count
  SHL  AH,CL    ;shift right 3 bits to pos 6,5,4
  OR  AL,AH    ;combine for & back to form attribute byte
  MOV  ATTRIB,AL  ;move it to STORAGE
;
;  convert 1 and 0 to 6 and 7 for routine call
;
  MOV  BX,FUNCT  ;move function into bx
  CMP  BL,0    ;compare to one
  JG  F6    ;if 1 then function is 6
  MOV  AH,7H    ;set function 7
  JMP  OUT1    ;jump around
F6:  MOV  AH,6H    ;set function 6
OUT1:  MOV  CALNU,AH  ;move it to storage
;
;
; set up for bios rom call 10 function 6 (scroll up )
;
  PUSH  BX
  MOV  BX,LINES  ;set # of lines to scroll or 0 to clear
  MOV  AL,BL    ;put in pass register
  MOV  BX,ULROW  ;set upper left row of block 0-24
  MOV  CH,BL    ;put in pass register
  MOV  BX,ULCOL  ;set upper left column of block 0-79
  MOV  CL,BL    ;put in pass register
  MOV  BX,LRROW  ;set lower right row of block 0-24
  MOV  DH,BL    ;put in pass register
  MOV  BX,LRCOL  ;set lower right column of block 0-79
  MOV  DL,BL    ;put in pass register
  MOV  BL,CALNU  ;set call number 6 to scroll up 7 down
  MOV  AH,BL    ;put in pass register
  MOV  BL,ATTRIB  ;set color attribute byte
  MOV  BH,BL    ;put in pass register
  INT  10H    ; make bios call
  POP  BX
;
FINISH: POP  ES
  POP  DS
  POP  BP
  RET  16    ;return to basic
CLR  ENDP
CSEG  ENDS
  END


Tags:汇编 源码 系列

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