PAGE 56,132
;
.386
;
; SEGMENT definitions and order
;
; July 2008
; Add basic IP decoding
; Feb 2012
; Created from MONDECODE to provide a transparent decode for MIC-E frames
;* 32 Bit code
_TEXT SEGMENT DWORD USE32 PUBLIC 'CODE'
_TEXT ENDS
;* Contains 32 Bit data
_BPQDATA SEGMENT DWORD PUBLIC 'DATA'
_BPQDATA ENDS
ASSUME CS:FLAT, DS:FLAT, ES:FLAT, SS:FLAT
_BPQDATA SEGMENT
CR EQU 0DH
LF EQU 0AH
D10 DW 10
D60 DD 60
D3600 DD 3600
D86400 DD 86400
TIMESTAMP DD 0
NEWVALUE DW 0
WORD10 DW 10
WORD16 DW 16
;
; BASIC LINK LEVEL MESSAGE BUFFER LAYOUT
;
MESSAGE STRUC
MSGCHAIN DD ? ; CHAIN WORD
MSGPORT DB ? ; PORT
MSGLENGTH DW ? ; LENGTH
MSGDEST DB 7 DUP (?) ; DESTINATION
MSGORIGIN DB 7 DUP (?) ; ORIGIN
;
; MAY BE UP TO 56 BYTES OF DIGIS
;
MSGCONTROL DB ? ; CONTROL BYTE
MSGPID DB ? ; PROTOCOL IDENTIFIER
MSGDATA DB ? ; START OF LEVEL 2 MESSAGE
;
MESSAGE ENDS
;
;
;
; L4FLAGS DEFINITION
;
L4BUSY EQU 80H ; BNA - DONT SEND ANY MORE
L4NAK EQU 40H ; NEGATIVE RESPONSE FLAG
L4MORE EQU 20H ; MORE DATA FOLLOWS - FRAGMENTATION FLAG
L4CREQ EQU 1 ; CONNECT REQUEST
L4CACK EQU 2 ; CONNECT ACK
L4DREQ EQU 3 ; DISCONNECT REQUEST
L4DACK EQU 4 ; DISCONNECT ACK
L4INFO EQU 5 ; INFORMATION
L4IACK EQU 6 ; INFORMATION ACK
;
NULL EQU 00H
CR EQU 0DH
LF EQU 0AH
;
PORT_MSG DB ' Port=',NULL
UI_MSG DB 'UI',NULL
;-----------------------------------------------------------------------------;
; Parameter area for received frame ;
;-----------------------------------------------------------------------------;
PORT_NO DB 0 ; Received port number 0 - 256
VERSION_NO DB 0 ; Version 1 or 2 1,2
POLL_FINAL DB 0 ; Poll or Final ? P,F
COMM_RESP DB 0 ; Command or Response C,R
FRAME_TYPE DB 0 ; Frame Type UI etc in Hex
PID DB 0 ; Protocol ID
FRAME_LENGTH DD 0 ; Length of frame 0 - 65...
NR DB 0 ; N(R) Flag
NS DB 0 ; N(S) Flag
INFO_FLAG DB 0 ; Information Packet ? 0 No, 1 Yes
;
; HDLC COMMANDS (WITHOUT P/F)
;
UI EQU 3
SABM EQU 2FH
DISC EQU 43H
DM EQU 0FH
UA EQU 63H
FRMR EQU 87H
RR EQU 1
RNR EQU 5
REJ EQU 9
;
PFBIT EQU 10H ; POLL/FINAL BIT IN CONTROL BYTE
CRLF DB 0DH,0AH
AX25CALL DB 7 DUP (0) ; WORK AREA FOR AX25 <> NORMAL CALL CONVERSION
NORMCALL DB 10 DUP (0) ; CALLSIGN IN NORMAL FORMAT
NORMLEN DD 0 ; LENGTH OF CALL IN NORMCALL
;
TENK DD 10000
DD 1000
WORD100 DD 100
DWORD10 DD 10
;
ACCUM DB 4 DUP (0)
CONVFLAG DB 0
SUPPRESS DB 0 ; ZERO SUPPRESS FLAG
SAVEDI DD 0
SAVESI DD 0
_BPQDATA ENDS
_TEXT SEGMENT PUBLIC 'CODE'
PUBLIC _APRSMONDECODE
EXTRN DISPLAY_BYTE_1:NEAR, DISPLAY_BYTE_2:NEAR, DISPADDR:NEAR, NORMSTR:NEAR
_APRSMONDECODE:
;
; esi=message, edi=buffer
;
MOV SAVESI,ESI
MOV SAVEDI,EDI
MOV TIMESTAMP,EAX
;
; GET THE CONTROL BYTE, TO SEE IF THIS FRAME IS TO BE DISPLAYED. We Should only get UI frames
;
PUSH ESI
MOV ECX,9 ; MAX DIGIS
CTRLLOOP:
TEST BYTE PTR MSGCONTROL-1[ESI],1
JNZ CTRLFOUND
ADD ESI,7
LOOP CTRLLOOP
;
; INVALID FRAME
;
POP ESI
MOV ECX,0
RET
CTRLFOUND:
MOV AL,MSGCONTROL[ESI]
POP ESI
;
TEST AL,1 ; I FRAME
JZ IFRAME
AND AL,NOT PFBIT ; CLEAR P/F
CMP AL,3 ; UI
JE OKTOTRACE ; ALWAYS DO UI
IFRAME:
MOV ECX,0
RET
OKTOTRACE:
;
;-----------------------------------------------------------------------------;
; Get the port number of the received frame ;
;-----------------------------------------------------------------------------;
mov CL,MSGPORT[ESI]
mov PORT_NO,CL
mov AH,MSGDEST+6[ESI]
mov AL,MSGORIGIN+6[ESI]
mov COMM_RESP,0 ; Clear Command/Response Flag
;-----------------------------------------------------------------------------;
; Is it a Poll/Final or Command/Response ;
;-----------------------------------------------------------------------------;
test AH,80H
mov COMM_RESP,'C'
jnz NOT_RESPONSE
mov COMM_RESP,'R'
NOT_RESPONSE:
;-----------------------------------------------------------------------------;
; Is this version 1 or 2 of AX25 ? ;
;-----------------------------------------------------------------------------;
xor AH,AL
test AH,80H
mov VERSION_NO,1
je VERSION_1
mov VERSION_NO,2
VERSION_1:
;
; DISPLAY TIMESTAMP AND T/R FLAG
;
MOV EAX,TIMESTAMP
mov EDX,0
DIV D86400
MOV EAX,EDX
MOV edx,0
DIV D3600
CALL DISPLAY_BYTE_2
MOV AL,':'
CALL PUTCHAR
MOV EAX,EDX
MOV EDX,0
DIV D60 ; MINS IN AX, SECS IN DX
PUSH DX
CALL DISPLAY_BYTE_2
MOV AL,':'
CALL PUTCHAR
POP AX ; SECS
CALL DISPLAY_BYTE_2
MOV AL,'R'
TEST PORT_NO,80H
JZ TR
MOV AL,'T'
TR:
CALL PUTCHAR
MOV AL,' '
CALL PUTCHAR
;-----------------------------------------------------------------------------;
; Display Origin Callsign ;
;-----------------------------------------------------------------------------;
PUSH ESI
lea ESI,MSGORIGIN[ESI]
call CONVFROMAX25
mov ESI,OFFSET NORMCALL
call DISPADDR
POP ESI
PUSH ESI
mov AL,'>'
call PUTCHAR
;-----------------------------------------------------------------------------;
; Display Destination Callsign ;
;-----------------------------------------------------------------------------;
lea ESI,MSGDEST[ESI]
call CONVFROMAX25
mov ESI,OFFSET NORMCALL
call DISPADDR
pop ESI
movzx EAX,MSGLENGTH[ESI]
mov FRAME_LENGTH,EAX
mov CX,8 ; Max number of digi-peaters
;-----------------------------------------------------------------------------;
; Display any Digi-Peaters ;
;-----------------------------------------------------------------------------;
NEXT_DIGI:
test MSGORIGIN+6[ESI],1
jnz NO_MORE_DIGIS
add ESI,7
sub FRAME_LENGTH,7 ; Reduce length
push ECX
push ESI
lea ESI,MSGORIGIN[ESI]
call CONVFROMAX25 ; Convert to call
push EAX ; Last byte is in AH
mov AL,','
call PUTCHAR
mov ESI,OFFSET NORMCALL
call DISPADDR
pop EAX
test AH,80H
jz NOT_REPEATED
; We should only put a * on the last repeated
test AH,1 ; if last address must be last repeated
jnz NEEDSTAR
pop ESI
test MSGORIGIN+13[ESI],80H
push ESI
jnz NOSTAR ; Repeated by next
NEEDSTAR:
mov AL,'*'
call PUTCHAR
NOSTAR:
NOT_REPEATED:
pop ESI
pop ECX
loop NEXT_DIGI
NO_MORE_DIGIS:
;----------------------------------------------------------------------------;
; Display the Port No of the frame ;
;----------------------------------------------------------------------------;
mov EBX,OFFSET PORT_MSG
call NORMSTR
mov AL,PORT_NO
AND AL,7FH
call DISPLAY_BYTE_1
;
mov AL,' '
call PUTCHAR
;-----------------------------------------------------------------------------;
; If this is Version 2 get the Poll/Final Bit ;
;-----------------------------------------------------------------------------;
mov POLL_FINAL,0 ; Clear Poll/Final Flag
mov AL,MSGCONTROL[ESI] ; Get control byte
cmp COMM_RESP,'C'
jne NOT_COMM
test AL,PFBIT
je NOT_POLL
mov POLL_FINAL,'P'
NOT_POLL:
NOT_COMM:
cmp COMM_RESP,'R'
jne NOT_RESP
test AL,PFBIT
je NOT_FINAL
mov POLL_FINAL,'F'
NOT_FINAL:
NOT_RESP:
;-----------------------------------------------------------------------------;
; Start displaying the frame information ;
;-----------------------------------------------------------------------------;
and AL,NOT PFBIT ; Remove P/F bit
mov FRAME_TYPE,AL
mov AL,'<' ; Print "<"
call PUTCHAR
mov NR,0 ; Reset all the flags
mov NS,0
mov INFO_FLAG,0
mov AL,FRAME_TYPE
cmp AL,UI
je UI_FRAME
MOV ECX,0
RET
UI_FRAME:
mov EBX,OFFSET UI_MSG
call NORMSTR
;----------------------------------------------------------------------------;
; If Version 2 Then display P/F C/R Information ;
;----------------------------------------------------------------------------;
cmp VERSION_NO,2
jne NOT_VERSION_2
mov AL,' '
call PUTCHAR
mov AL,COMM_RESP ; Print Command/Response Flag
call PUTCHAR
cmp POLL_FINAL,0
je NO_POLL_FINAL
mov AL,' '
call PUTCHAR
mov AL,POLL_FINAL ; Print Poll/Final Flag if Set
call PUTCHAR
NO_POLL_FINAL:
NOT_VERSION_2:
mov AL,'>'
call PUTCHAR
;----------------------------------------------------------------------------;
; Find the PID if an information frame ;
;----------------------------------------------------------------------------;
mov AL,0
lea ESI,MSGPID[ESI]
lodsb
mov PID,AL
MOV ECX,FRAME_LENGTH
;----------------------------------------------------------------------------;
; Display the rest of the frame (If Any) ;
;----------------------------------------------------------------------------;
mov AL,':'
call PUTCHAR
XOR AL,AL ; IN CASE EMPTY
sub ECX,23
JZ NO_INFO ; EMPTY I FRAME
JNS @F
; Length Negative
PUSH EAX
push edi
mov [edi],0 ; Null Terminate
JMP NO_INFO
@@:
;
; PUT TEXT ON A NEW LINE
;
PUSH ECX
MOV AL,0DH
PUSH ESI
CALL PUTCHAR
POP ESI
POP ECX
cmp ECX,257
jl LENGTH_OK
mov ECX,256
LENGTH_OK:
push ECX
lodsb
call PUTCHAR ; APRS requires all chars to be passed
pop ECX
loop LENGTH_OK
NO_INFO:
;
; ADD CR UNLESS DATA ALREADY HAS ONE
;
CMP AL,CR
JE NOTANOTHER
mov AL,CR
call PUTCHAR
NOTANOTHER:
MOV ECX,EDI
SUB ECX,SAVEDI
RET
PUTCHAR:
STOSB
RET
CONVFROMAX25:
;
; CONVERT AX25 FORMAT CALL IN [SI] TO NORMAL FORMAT IN NORMCALL
; RETURNS LENGTH IN CX AND NZ IF LAST ADDRESS BIT IS SET
;
PUSH EDI ; SAVE BUFFER
PUSH ESI ; SAVE
MOV EDI,OFFSET NORMCALL
MOV ECX,10 ; MAX ALPHANUMERICS
MOV AL,20H
REP STOSB ; CLEAR IN CASE SHORT CALL
MOV EDI,OFFSET NORMCALL
MOV CL,6
CONVAX50:
LODSB
CMP AL,40H
JE CONVAX60 ; END IF CALL - DO SSID
SHR AL,1
STOSB
LOOP CONVAX50
CONVAX60:
POP ESI
ADD ESI,6 ; TO SSID
LODSB
MOV AH,AL ; SAVE FOR LAST BIT TEST
SHR AL,1
AND AL,0FH
JZ CONVAX90 ; NO SSID - FINISHED
;
MOV BYTE PTR [EDI],'-'
INC EDI
CMP AL,10
JB CONVAX70
SUB AL,10
MOV BYTE PTR [EDI],'1'
INC EDI
CONVAX70:
ADD AL,30H ; CONVERT TO DIGIT
STOSB
CONVAX90:
MOV ECX,EDI
SUB ECX,OFFSET NORMCALL
MOV NORMLEN,ECX ; SIGNIFICANT LENGTH
TEST AH,1 ; LAST BIT SET?
POP EDI
RET
_TEXT ENDS
END