這個都是過去DOS時代的匯編源碼，雖然已經過去了，但是對於學習匯編還是有幫助的，匯編語言只是程序員一門基礎語言，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
