home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Cream of the Crop 1
/
Cream of the Crop 1.iso
/
UTILITY
/
TSRSRC34.ARJ
/
RAMFREE.ASM
< prev
next >
Wrap
Assembly Source File
|
1991-11-22
|
3KB
|
86 lines
;RAMFREE
;determine amount of available RAM without using CHKDSK
;Kim Kokkonen, TurboPower Software, 6/85
;written for MASM or TASM
;Updated 10/20/91
; work for free memory greater than 640K
; add size of environment block
;
Cseg segment public para
assume cs:Cseg, ds:Cseg, es:Cseg
org 100H
ramfree proc near
;shrink memory available to this program
coment: mov bx,offset theend
add bx,15
mov cl,4
shr bx,cl ;convert bytes to paragraphs
mov ah,4AH
int 21H ;DOS SETBLOCK function
;try to allocate the maximum memory
mov ah,4AH
mov bx,0FFFFH
int 21H ;use SETBLOCK again
;BX contains paragraphs available
;add size of environment
mov ax,ds:[002CH]
dec ax
mov es,ax
add bx,es:[0003H]
;convert paragraphs to a doubleword number of bytes in dx:ax
mov ax,bx
xor dx,dx
mov dl,ah ;dl will contain top four bytes of ah
mov cl,4
shr dx,cl
shl ax,cl
;convert doubleword dx:ax to an ASCII string
mov di,offset outp$ ;di indexes next output position
mov si,offset digits ;si indexes digit table
nextd: mov cx,[si] ;low word of digit
add si,2
mov bx,[si] ;high word of digit
add si,2
xor bp,bp ;counter for this digit
nextc: sub ax,cx
sbb dx,bx
jc ddone ;jump if carry
inc bp ;else increment counter
jmp nextc
ddone: add ax,cx ;undo last subtraction
adc dx,bx
mov cx,bp ;counter into cx
cmp di,offset outp$ ;first output character?
jne store ;output zeros if not leading
jcxz chknc ;no output for leading zeros
store: or cl,30H ;convert count to digit
mov [di],cl ;store output
inc di ;next output position
chknc: cmp si,offset theend ;all of table?
jb nextd ;loop if not
;now output the string and halt
mov dx,offset bmess$
mov ah,09H
int 21H ;print string
mov ax,4C00H
int 21H
ramfree endp
;data area
bmess$ db 'RAM bytes available: '
outp$ db 32,32,32,32,32,32,32,13,10,36 ;ASCII output string
digits dd 1000000,100000,10000,1000,100,10,1 ;conversion table
theend label byte
Cseg ends
end ComEnt