AM79C90 Advanced Micro Devices, AM79C90 Datasheet - Page 48

• Manufacturer Part Number: AM79C90
• Description: CMOS Local Area Network Controller for Ethernet (C-LANCE)
• Manufacturer: Advanced Micro Devices

Hash Filter Generation Programs for
Logical Addressing
80x86 computer program example to generate the hash filter, for multicast addressing in the C-LANCE.
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= 1DB6
= 04C1
0000
0000
0000 50
0001 53
0002 51
0003 52
0004 55
0005 B8 FFFF
0008 BA FFFF
000B B5 03
000D 8B 2C
000F 83 C6 02
0012 B1 10
0014 8B DA
0016 D1 C3
0018 33 DD
001A D1 E0
001C D1 D2
001E 81 E3 0001
0022 74 07
APPENDIX A
;
;
;
;
;
;
;
;
POLYL
POLYH
;
CSE61
;
SETHASH PROC
;
;
SETH10:
;
SETH20:
;
;
SUBROUTINE TO SET A BIT IN THE HASH FILTER FROM A
GIVEN ETHERNET LOGICAL ADDRESS
ON ENTRY Sl POINTS TO THE LOGICAL ADDRESS WITH LSB FIRST
ON RETURN Sl POINTS TO THE BYTE AFTER THE LOGICAL ADDRESS
PUBLIC SETHASH
ASSUME CS:CSE61
EOU
EQU
SEGMENT PUBLIC ‘CODE’
PUSH
PUSH
PUSH
PUSH
PUSH
MOV
MOV
MOV
MOV
ADD
MOV
MOV
ROL
XOR
SAL
RCL
AND
JZ
PERFORM XOR OPERATION WHEN CONTROL BIT= 1
ALL OTHER REGISTERS ARE UNMODIFIED
1DB6H
04C1H
NEAR
AX
BX
CX
DX
BP
AX,0FFFFH
DX,0FFFFH
CH,3
BP,[S1]
S1,2
CL,16
BX,DX
BX,1
BX,BP
AX,1
DX,1
BX,0001H
SETH30
Dl POINTS TO THE HASH FILTER WITH LSB FIRST
Am79C90
;CRC POLYNOMINAL TERMS
;SAVE ALL REGISTERS
;AX,DX =CRC ACCUMULATOR
;PRESET CRC ACCUMULATOR TO ALL 1’S
;CH =WORD COUNTER
;GET A WORD OF ADDRESS
;POINT TO NEXT ADDRESS
;CL=BIT COUNTER
;GET HIGH WORD OF CRC
;PUT CRC31 TO LSB
;COMBINE CRC31 WITH INCOMING BIT
;LEFT SHIFT CRC ACCUMULATOR
;BX=CONTROL BIT
;DO NOT XOR IF CONTROL BIT = 0