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