;*************************** AMUS Program Label ******************************
; Filename: HASH.SBR Date: 06/12/89
; Category: DISK Hash Code: 644-125-730-247 Version: 1.0(102)
; Initials: AMI Name: AMI BAR-YADIN
; Company: UNITED FASHIONS OF TEXAS Telephone #: 5126312277
; Related Files:
; Min. Op. Sys.: NA Expertise Level: BEG
; Special:
; Description: Compute hash code of data in any size/type variable with
; control over the number of bytes to be used and the number of
; passes. (Did you know DIR/H reads each file twice?)
;*****************************************************************************
;* Updated on 12-Jun-89 at 9:01 PM by ; edit time: 1:13:22 *;
; HASH.SBR
;
; syntax:
; xcall hash,XVAR,RESULT {,SIZE {,FLAG }}
; where:
; XVAR,X input data to compute a hash total of.
; Must be even number of bytes or the LAST byte is not used
; RESULT,S or hash total is returned in ASCII (octal) aaa-bbb-ccc-ddd
; RESULT,B,4 or hash total is returned as a longword
; RESULT,X,4 hash total is returned as 4 bytes
; SIZE,F optional, number of bytes in XVAR to use
; must be even or will be rounded UP (1 byte added if odd)
; if zero, or not given, all of XVAR is used
; FLAG,F optional, number of passes for hash algorithm.
; if zero, or not given, two passes are done.
; The standard (DIR/H) uses two passes.
;
;
; portions (c) by Alphamicro systems. (the actual hash algorithm)
; (c) 1989 by Ami Bar-Yadin
;
;-All commercial rights reserved, etc.
;-No warranties and/or guarranties of any kind, etc.
;-Not responsible for damages resulting from the use of this program, etc.
;-My employer (United Fashions) has nothing to do with this program and
; should not be blamed for it.
;
; I can be reached at:
; United Fashions of Texas, Inc.
; 200 Ash Ave.
; McAllen, TX 78501
; (512) 631-2277
; 8am-6pm
;
HASH:
CMPW @A3,#2
JLO ERR1
MOV #2,D2 ; default two passes
BADRS 1,A2 ; index source data
MOV A2,D6 ; trap odd address
BTST #0,D6
JNE ERR2
BSIZE 1,D0 ; get input data size in bytes
CMPW @A3,#3 ; is SIZE present?
BLO 20$ ; no
BADRS 3,A0 ; index 3rd arguent: SIZE
FFTOL @A0,D7 ; get SIZE
TST D7 ; is it zero?
BEQ 20$ ; yes. use data size.
BTST #0,D7 ; is it even?
BEQ 10$ ; yes.
INC D7 ; no, round it UP.
10$: CMP D7,D0 ; is it larger then data size?
BHIS 20$ ; yes. use data size
MOV D7,D0 ; no. use SIZE bytes
20$: CMPW @A3,#4 ; FLAGS present?
BLO 30$ ; no.
BADRS 4,A6 ; index 4th argument: FLAGS
FFTOL @A6,D7 ; get FLAGS
TST D7 ; is it zero?
BEQ 30$ ; yes. use default
AND #0F,D7 ; par is down to 15
MOV D7,D2 ; use FLAGS passes.
30$: CLR D3 ; clear hash code totals
CLR D4
LSR D0,#1 ; compute number of words in data
BEQ 50$ ; if zero, EXIT
DEC D2 ; pre-dec for DBx
40$: CALL CLCHSH ; one hash code pass
DBF D2,40$ ; loop for all passes
50$: CMPW @A3,#3 ; is SIZE present?
BLO 60$ ; no
FLTOF D0,@A0 ; yes, return number of words.
60$: BADRS 2,A2 ; index 2nd argument: RESULT
BSIZE 2,D2 ; get size of RESULT
BTYPE 2,D1 ; get type of RESULT
AND #0F,D1
BEQ 80$ ; unformatted(X): 4 bytes
CMPB D1,#4 ; float(F): 32-bit signed
BEQ 90$
CMPB D1,#6 ; binary(B): 4 bytes
BEQ 80$
CMP D2,#16. ; string(S): 15-chars plus null
JLO ERR3
CALL PRTHSH ; output hash in std ascii format
70$: RTN
; output hash in lsb..msb order (basic B,4)
80$: CMP D2,#4 ; make sure we have 4 bytes
JLO ERR3
MOVW D3,D7 ; d3-lo word
MOVB D7,(A2)+ ; d3-lo
RORW D7,#8.
MOVB D7,(A2)+ ; d4-hi
MOVW D4,D7 ; d4-hi word
MOVB D4,(A2)+ ; d4-lo
RORW D7,#8.
MOVB D7,(A2)+ ; d4-hi
JMP 70$
; output byte a basic float
90$: MOVW D4,D7 ; get HI word
SWAP D7 ; swap words
MOVW D3,D7 ; get LO word
FLTOF D7,@A2 ; output to float
JMP 70$
;---
; compute hash code of data @A2, D0 words long
; D3,D4-in/out hash code totals
;
CLCHSH: SAVE D0,D2,A2
CLR D7
10$: MOVW (A2)+,D2
ADDW D2,D3
ADDXW D7,D4
SUBW D0,D4
ADDXW D7,D3
ADDW D3,D4
ADDXW D7,D3
LSLW D3,#1
ROXLW D4,#1
ADDXW D7,D3
DEC D0
BNE 10$
REST A2,D2,D0
RTN
