mirror of
https://github.com/vxunderground/MalwareSourceCode
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112 lines
3.9 KiB
NASM
112 lines
3.9 KiB
NASM
title FREE.ASM
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page,132
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cseg segment para 'code'
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assume cs:cseg
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main proc far
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org 100h
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start:
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jmp begin
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banner db 0ah,'FREE Vers 1.0 - Sept. 1985 - by Art Merrill',0dh,0ah,'$'
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db 'Copyright (C) 1985',0dh,0ah,'$'
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db 'Ziff-Davis Publishing Company',0dh,0ah,'$'
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total: db 0ah,8 dup(0),' bytes total disk space',0dh,0ah
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diff: db 8 dup(0),' bytes allocated',0dh,0ah
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bytes: db 8 dup(0),' bytes available on disk',0dh,0ah,0ah,'$'
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hltotal: dw 0,0
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hlbytes: dw 0,0
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begin:
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mov dx,offset banner
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mov ah,9
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int 21h
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mov si,5ch ;address of selected drive
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mov dl,[si]
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mov ah,36h ;get disk free space
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int 21h
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push ax ;save for total bytes
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push cx ;save for total bytes
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push dx ;save for total bytes
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mul bx ;get total clusters
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mul cx ;get total bytes
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std
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mov di,offset hlbytes+2
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xchg ax,dx
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stosw
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xchg ax,dx
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stosw
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mov di,offset bytes+7 ;storage for ascii printout
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call ascii
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pop dx ;get back total clusters
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pop cx ;get back bytes per sector
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pop ax ;get back sectors per cluster
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mul dx ;total clusters
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mul cx ;bytes per sector
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mov di,offset hltotal+2 ;same routine as above to get
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xchg ax,dx ; total bytes
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stosw
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xchg ax,dx
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stosw
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mov di,offset total+8 ;storage for ascii printout
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call ascii
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mov ax,word ptr hltotal+2 ;calculate difference between
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sub ax,word ptr hlbytes+2 ; total bytes and bytes allocated
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xchg ax,dx ; to get total bytes remaining
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mov ax,word ptr hltotal
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sub ax,word ptr hlbytes
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jnc skip
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dec dx ;adjust total for carry
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skip:
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mov di,offset diff+7 ;storage for ascii printout
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call ascii
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mov dx,offset total ;print results
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mov ah,9
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int 21h
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int 20h ;exit
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main endp
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ascii proc near
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xchg bp,dx ;save high word
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mov bx,0ah ;divisor
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mov cl,30h ;conversion for ascii
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rpt1:
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cmp bp,0 ;are we done with high words
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jz rpt2 ;yes
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xchg ax,bp ;no-get high word
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xor dx,dx ;clear dx
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div bx
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xchg bp,ax ;this will be the new high word
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div bx ;divide low word + remainder
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or dl,cl ;convert hex value to ascii
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mov [di],dl ;quotient into storage
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dec di ;step back one byte
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jmp rpt1 ;go again
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rpt2:
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xor dx,dx ;clear dx
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div bx
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or dl,cl ;convert hex value to ascii
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mov [di],dl ;quotient into storage
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dec di ;step back one byte
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cmp ax,0 ;are we done?
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jnz rpt2 ;no
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ret ;yes
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ascii endp
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cseg ends
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end start
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