Point Programming 1

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Assembly Source File | 1992-06-23 | 6.3 KB | 275 lines

;$Author: DCODY $ ;$Date: 23 Jun 1992 16:32:18 $ ;$Header: W:/sccs/misc/histo.asv 1.1 23 Jun 1992 16:32:18 DCODY $ ;$Log: W:/sccs/misc/histo.asv $ ; ; Rev 1.1 23 Jun 1992 16:32:18 DCODY ; PAS2 update ; ; Rev 1.0 15 Jun 1992 09:39:52 BCRANE ; Initial revision. ;$Logfile: W:/sccs/misc/histo.asv $ ;$Modtimes$ ;$Revision: 1.1 $ Title Media Vision Histogram routines page 64,131 ; /*\ ;---|*|----====< HISTO.ASM >====---- ;---|*| ;---|*| These routines create a histogram from the block of PCM samples ;---|*| ;---|*| MakeHistoGram (char far *, int-1, int-2) ;---|*| MakeHalfHistoGram (char far *, int-1, int-2) ;---|*| ;---|*| char far * (wParm1) is the buffer pointer ;---|*| int-1 (wParm2) is the buffer length in bytes ;---|*| int-2 (wParm3) is the offset from the center line to accumulate ;---|*| ;---|*| The Return value is the count of samples over the offset ;---|*| ; \*/ .xlist include model.inc include masm.inc ;;;;;;;;include target.inc .list .data public HistoGram256 HistoGram256 dw 256 dup(0) ; 256 word table for histogram accum extrn __pcmdatasize:byte ; data size - 8 or 16 bit PCM .code ; /*\ ;---|*|------------------=============================------------------ ;---|*|------------------====< MakeHalfHistoGram >====------------------ ;---|*|------------------=============================------------------ ; \*/ ; ; This routine folds the high order samples into the low order, via ; ones compliment. Since it uses ones compliment, the folded values ; will shift down one value (an effective increase in aplituded by ; a factor of 1/256). The benefit is a faster accumulation. This ; routine is used to find how many samples pass the threshold of noise. ; This "noise" is wParm3, the offset from the center line. ; public MakeHalfHistoGram MakeHalfHistoGram proc push bp mov bp,sp ; ; save the critcals ; push es push di push si ; ; flush the table ; push ds ; clear the block pop es lea di,HistoGram256 sub ax,ax mov cx,100h cld rep stosw lea di,HistoGram256 ; es:di point to the table ; ; get the two parameters ; if @datasize les si,wParm1 ; get the target buffer pointer mov cx,wParm3 ; get the buffer length else mov si,wParm1 ; get the target buffer pointer mov cx,wParm2 ; get the buffer length endif ; ; handle the 16 bit data as 8 bit ; sub dx,dx ; dx has an XOR mask to convert 16 to 8 cmp __pcmdatasize,8 ; 8 bit data? jz @F ; yes, continue on... mov dx,0180h ; to flip the data byte to 8 bits shr cx,1 ; cut the buffer in half inc si ; point to the most significant byte ; @@: ; ; make the histogram ; mhhg05: if @datasize lods byte ptr es:[si] ; get the next byte of data else lodsb endif neg dh ; set the carry if 16 bit data adc si,0 ; adjust si to the next high byte xor al,dl ; if 16 bit data, convert to 8 bit cbw ; if al > 7f, do a 1s compliment xor al,ah cbw ; clear ah mov bx,ax add bx,ax inc wptr [di+bx] ; increment the word loop mhhg05 mov bx,cx ; clear bx ; ; count all the entries starting at the offset ; mov cl,80h if @datasize sub cl,bptr wParm4 ; cx holds the count else sub cl,bptr wParm3 ; cx holds the count endif lea si,HistoGram256 ; si points to the start of the table ; mhhg20: lodsw add bx,ax loop mhhg20 mov ax,bx ; return the count ; ; all done, exit home... ; pop si pop di pop es pop bp ret MakeHalfHistoGram endp ; /*\ ;---|*|---------------------=========================--------------------- ;---|*|---------------------====< MakeHistoGram >====--------------------- ;---|*|---------------------=========================--------------------- ; \*/ ; ; This routine builds a full histogram of the caller's buffer. ; public MakeHistoGram MakeHistoGram proc push bp mov bp,sp ; ; save the critcals ; push es push di push si ; ; flush the table ; push ds ; clear the block pop es lea di,HistoGram256 sub ax,ax mov cx,100h cld rep stosw lea di,HistoGram256 ; es:di point to the table ; ; get the two parameters ; if @datasize les si,wParm1 ; get the target buffer pointer mov cx,wParm3 ; get the buffer length else mov si,wParm1 ; get the target buffer pointer mov cx,wParm2 ; get the buffer length endif ; ; handle the 16 bit data as 8 bit ; sub dx,dx ; dx has an XOR mask to convert 16 to 8 cmp __pcmdatasize,8 ; 8 bit data? jz @F ; yes, continue on... mov dx,0180h ; to flip the data byte to 8 bits shr cx,1 ; cut the buffer in half inc si ; point to the most significant byte ; @@: ; ; make the histogram ; mhg05: if @datasize lods byte ptr es:[si] else lodsb endif neg dh ; set the carry if 16 bit data adc si,0 ; adjust si to the next high byte xor al,dl ; if 16 bit data, convert to 8 bit mov bx,ax shl bx,1 inc wptr [di+bx] loop mhg05 ; ; count all high entries based upon the offset ; if @datasize sub cl,bptr wParm4 ; cx holds the count else sub cl,bptr wParm3 ; cx holds the count endif lea si,HistoGram256 ; si points to the start of the table add si,100h ; move to the centerline add si,cx ; adjust to the starting index add si,cx sub cx,80h ; cx will hold an index from 80h to ffh neg cx and cx,07fh ; make sure its valid sub bx,bx ; bx holds the accumulated value ; mhg10: lodsw add bx,ax loop mhg10 ; ; count all the low entries based upon the offset ; mov cl,80h if @datasize sub cl,bptr wParm4 ; cx holds the count else sub cl,bptr wParm3 ; cx holds the count endif lea si,HistoGram256 ; si points to the start of the table ; mhg20: lodsw add bx,ax loop mhg20 mov ax,bx ; return the count ; ; all done, exit home... ; pop si pop di pop es pop bp ret MakeHistoGram endp ; end ;