gpsfuncs.asm

OpenSource GPS is software for x86 PCs that allows you to acquire, track and demodulate signals from

   ;	/*
   ;	     READ THE INPUT DATA FILE(s)
   ;	*/
   ;		  status=cold_start;       // for initialization, if we have enough data we
   ;	
	?debug	L 807
	mov	ax,seg _status
	mov	es,ax
	mov	word ptr es:_status,0
   ;	
   ;		  read_ion_utc();          // will switch to warm or hot start
   ;	
	?debug	L 808
	call	far ptr @read_ion_utc$qv
   ;	
   ;	     thetime=time(NULL);
   ;	
	?debug	L 809
	push	large 0
	call	far ptr _time
	add	sp,4
	mov	bx,seg _thetime
	mov	es,bx
	mov	word ptr es:_thetime+2,dx
	mov	word ptr es:_thetime,ax
   ;	
   ;	     read_almanac();
   ;	
	?debug	L 810
	call	far ptr @read_almanac$qv
   ;	
   ;	     dummy=satfind(0);
   ;	
	?debug	L 811
	push	0
	push	ss
	lea	ax,word ptr [bp-24]
	push	ax
	push	cs
	call	near ptr @satfind$qc
	add	sp,6
   ;	
   ;	}
   ;	
	?debug	L 812
	pop	di
	pop	si
	leave	
	ret	
	?debug	C E60564756D6D791B02E8FF000002696404040200+
	?debug	C 00
	?debug	E
	?debug	E
@read_initial_data$qv	endp
	assume	cs:GPSFUNCS_TEXT,ds:DGROUP
@receiver_loc$qv	proc	far
   ;	
   ;	llh receiver_loc(void)
   ;	
	?debug	L 829
	?debug	B
	push	bp
	mov	bp,sp
	sub	sp,46
	push	si
	push	di
	?debug	B
	cmp	word ptr __stklen,sp
	ja	short @5@3
	call	far ptr F_OVERFLOW@
@5@3:
   ;	
   ;	{
   ;			float latitude,longitude,height;
   ;	      char  text[10];
   ;	      llh result;
   ;	      result.lat=0.0;
   ;	
	?debug	L 834
	fldz	
	fstp	qword ptr [bp-46]
   ;	
   ;	      result.lon=0.0;
   ;	
	?debug	L 835
	fldz	
	fstp	qword ptr [bp-38]
   ;	
   ;	      result.hae=0.0;
   ;	
	?debug	L 836
	fldz	
	fstp	qword ptr [bp-30]
   ;	
   ;	/*
   ;	     READ THE CURRENT LOCATION DATA FILE
   ;	*/
   ;	     if ((in = fopen("CURLOC.DAT", "rt")) == NULL)
   ;	
	?debug	L 840
	push	ds
	push	offset DGROUP:s@+111
	push	ds
	push	offset DGROUP:s@+100
	fwait	
	call	far ptr _fopen
	add	sp,8
	mov	bx,seg _in
	mov	es,bx
	mov	word ptr es:_in+2,dx
	mov	word ptr es:_in,ax
	or	ax,dx
	jne	short @5@5
   ;	
   ;	    {
   ;	     printf("Cannot open curloc.dat file.\n");
   ;	
	?debug	L 842
	push	ds
	push	offset DGROUP:s@+114
	call	far ptr _printf
	add	sp,4
   ;	
   ;	     status=cold_start;
   ;	
	?debug	L 843
	mov	ax,seg _status
	mov	es,ax
	mov	word ptr es:_status,0
   ;	
   ;	    }
   ;	
	?debug	L 844
	jmp	@5@6
@5@5:
   ;	
   ;		 else
   ;	    {
   ;	     fscanf(in,"%10s",text);
   ;	
	?debug	L 847
	push	ss
	lea	ax,word ptr [bp-22]
	push	ax
	push	ds
	push	offset DGROUP:s@+144
	mov	ax,seg _in
	mov	es,ax
	push	dword ptr es:_in
	call	far ptr _fscanf
	add	sp,12
   ;	
   ;	     fscanf(in,"%f",&latitude);
   ;	
	?debug	L 848
	push	ss
	lea	ax,word ptr [bp-4]
	push	ax
	push	ds
	push	offset DGROUP:s@+149
	mov	ax,seg _in
	mov	es,ax
	push	dword ptr es:_in
	call	far ptr _fscanf
	add	sp,12
   ;	
   ;	     fscanf(in,"%10s",text);
   ;	
	?debug	L 849
	push	ss
	lea	ax,word ptr [bp-22]
	push	ax
	push	ds
	push	offset DGROUP:s@+152
	mov	ax,seg _in
	mov	es,ax
	push	dword ptr es:_in
	call	far ptr _fscanf
	add	sp,12
   ;	
   ;	     fscanf(in,"%f",&longitude);
   ;	
	?debug	L 850
	push	ss
	lea	ax,word ptr [bp-8]
	push	ax
	push	ds
	push	offset DGROUP:s@+157
	mov	ax,seg _in
	mov	es,ax
	push	dword ptr es:_in
	call	far ptr _fscanf
	add	sp,12
   ;	
   ;	     fscanf(in,"%10s",text);
   ;	
	?debug	L 851
	push	ss
	lea	ax,word ptr [bp-22]
	push	ax
	push	ds
	push	offset DGROUP:s@+160
	mov	ax,seg _in
	mov	es,ax
	push	dword ptr es:_in
	call	far ptr _fscanf
	add	sp,12
   ;	
   ;	     fscanf(in,"%f",&height);
   ;	
	?debug	L 852
	push	ss
	lea	ax,word ptr [bp-12]
	push	ax
	push	ds
	push	offset DGROUP:s@+165
	mov	ax,seg _in
	mov	es,ax
	push	dword ptr es:_in
	call	far ptr _fscanf
	add	sp,12
   ;	
   ;		  result.lat=latitude/57.296;
   ;	
	?debug	L 853
	fld	dword ptr [bp-4]
	fdiv	qword ptr DGROUP:s@+168
	fstp	qword ptr [bp-46]
   ;	
   ;	     result.lon=longitude/57.296;
   ;	
	?debug	L 854
	fld	dword ptr [bp-8]
	fdiv	qword ptr DGROUP:s@+168
	fstp	qword ptr [bp-38]
   ;	
   ;	     result.hae=height;
   ;	
	?debug	L 855
	fld	dword ptr [bp-12]
	fstp	qword ptr [bp-30]
	fwait	
@5@6:
   ;	
   ;	     }
   ;		  fclose(in);
   ;	
	?debug	L 857
	mov	ax,seg _in
	mov	es,ax
	push	dword ptr es:_in
	call	far ptr _fclose
	add	sp,4
   ;	
   ;		  return(result);
   ;	
	?debug	L 858
	lea	si,word ptr [bp-46]
	mov	ax,ss
	les	di,dword ptr [bp+6]
	push	ds
	mov	ds,ax
	mov	cx,12
	rep 	movsw	
	pop	ds
	mov	dx,word ptr [bp+8]
	mov	ax,word ptr [bp+6]
   ;	
   ;	}
   ;	
	?debug	L 859
	pop	di
	pop	si
	leave	
	ret	
	?debug	C E320036C6C6818001E1D
	?debug	C E321000A001A02
	?debug	C E322000400162000
	?debug	C E606726573756C742002D2FF0000047465787421+
	?debug	C 02EAFF0000066865696768740E02F4FF0000096C+
	?debug	C 6F6E6769747564650E02F8FF0000086C61746974+
	?debug	C 7564650E02FCFF00000672657475726E220A0600+
	?debug	C 0000
	?debug	E
	?debug	E
@receiver_loc$qv	endp
	assume	cs:GPSFUNCS_TEXT,ds:DGROUP
@navmess$qcc	proc	far
   ;	
   ;	void navmess(char prn,char ch)
   ;	
	?debug	L 876
	?debug	B
	push	bp
	mov	bp,sp
	sub	sp,228
	push	si
	push	di
	?debug	C E6026368020A080000000370726E020A06000000
	?debug	B
	cmp	word ptr __stklen,sp
	ja	short @6@3
	call	far ptr F_OVERFLOW@
@6@3:
   ;	
   ;	{
   ;	  int i,j,k;
   ;	  unsigned long isqra,ie;
   ;	  long iaf0,iomegadot,iomega0;
   ;	  char itgd,iaf2;
   ;	//  int icapl2;
   ;	  int iweek,iura,ihealth,iodc,iaf1;
   ;	  unsigned int itoe,itoc;
   ;	//  int fif;
   ;	  int iode,icrs,idn,icuc,icus,icic,iomegad;
   ;	  int icis,icrc,idoe,idot;
   ;	  unsigned int iae,iatoa;
   ;	//  static int i4page,i5page;
   ;	  int i4data,i5data,isv,iaomegad;
   ;	  long iaaf0,iaaf1,iadeli,iaomega0,im0,inc0,iw;
   ;	  unsigned long iasqr;
   ;	  long iaw,iam0,scale,ia0,ia1;
   ;	  char ial0,ial1,ial2,ial3,ibt0,ibt1,ibt2,ibt3;
   ;	  int  itot,iWNt,idtls,iWNlsf,iDN,idtlsf;//WNa
   ;	  int sfr,word,i4p,i5p;
   ;	  double r_sqra,r_inc0,r_ety;
   ;	  float d_toe;
   ;	//
   ;	//    assemble the 1500 data bits into subframes and words
   ;	//
   ;	//	gotoxy(1,24);
   ;	//	printf("->navmess prn %d  ch %d",prn,ch);
   ;	    d_toe=clock_tow-gps_eph[prn].toe;
   ;	
	?debug	L 904
	mov	al,byte ptr [bp+6]
	cbw	
	imul	ax,ax,196
	mov	dx,seg _gps_eph
	mov	bx,ax
	mov	es,dx
	fld	qword ptr es:_gps_eph[bx+28]
	mov	ax,seg _clock_tow
	mov	es,ax
	mov	eax,dword ptr es:_clock_tow
	mov	dword ptr [bp-180],eax
	mov	word ptr [bp-176],0
	mov	word ptr [bp-174],0
	fild	qword ptr [bp-180]
	fsubr	
	fstp	dword ptr [bp-172]
   ;	
   ;	    if (d_toe>302400.0) d_toe=d_toe-604800.0;
   ;	
	?debug	L 905
	fld	dword ptr [bp-172]
	fcomp	dword ptr DGROUP:s@+60
	fstsw	ax
	sahf	
	jbe	short @6@5
	fld	dword ptr [bp-172]
	fsub	dword ptr DGROUP:s@+64
	jmp	short @6@7
@6@5:
   ;	
   ;	    else if (d_toe<-302400.0)d_toe=d_toe+604800.0;
   ;	
	?debug	L 906
	fld	dword ptr [bp-172]
	fcomp	qword ptr DGROUP:s@+68
	fstsw	ax
	sahf	
	jae	short @6@8
	fld	dword ptr [bp-172]
	fadd	dword ptr DGROUP:s@+64
@6@7:
	fstp	dword ptr [bp-172]
	fwait	
@6@8:
   ;	
   ;		 j=0;
   ;	
	?debug	L 907
	mov	word ptr [bp-2],0
   ;	
   ;		 for (sfr=1;sfr<=5;sfr++)
   ;	
	?debug	L 908
	mov	word ptr [bp-142],1
	jmp	@6@21
@6@9:
   ;	
   ;		 {
   ;		   for (word=1;word<=10;word++)
   ;	
	?debug	L 910
	mov	word ptr [bp-144],1
	mov	word ptr [bp-182],4
	jmp	@6@19
@6@11:
   ;	
   ;		   {
   ;		 	  scale=536870912L;
   ;	
	?debug	L 912
	mov	dword ptr [bp-116],large 020000000h
   ;	
   ;		 	  sf[sfr][word]=0;
   ;	
	?debug	L 913
	mov	bx,word ptr [bp-142]
	imul	bx,bx,44
	add	bx,word ptr [bp-182]
	mov	ax,seg _sf
	mov	es,ax
	mov	dword ptr es:_sf[bx],large 0
   ;	
   ;		 	  for (i=0;i<=29;i++)
   ;	
	?debug	L 914
	xor	cx,cx
	jmp	short @6@16
@6@12:
   ;	
   ;		 	  {
   ;		 		  if (chan[ch].message[(j+chan[ch].offset)%1500]==1)
   ;	
	?debug	L 916
	mov	al,byte ptr [bp+8]
	cbw	
	imul	ax,ax,1738
	mov	dx,seg _chan
	mov	bx,ax
	mov	es,dx
	mov	ax,word ptr es:_chan[bx+1536]
	add	ax,word ptr [bp-2]
	mov	bx,1500
	cwd	
	idiv	bx
	mov	al,byte ptr [bp+8]
	cbw	
	imul	ax,ax,1738
	add	dx,ax
	mov	ax,seg _chan
	mov	bx,dx
	mov	es,ax
	mov	al,byte ptr es:_chan[bx+18]
	cbw	
	cmp	ax,1
	jne	short @6@14
   ;	
   ;		 		  sf[sfr][word]+=scale;
   ;	
	?debug	L 917
	mov	bx,word ptr [bp-142]
	imul	bx,bx,44
	add	bx,word ptr [bp-182]
	mov	ax,seg _sf
	mov	edx,dword ptr [bp-116]
	mov	es,ax
	add	dword ptr es:_sf[bx],edx
@6@14:
   ;	
   ;		 		  scale=scale>>1;
   ;	
	?debug	L 918
	mov	eax,dword ptr [bp-116]
	sar	eax,1
	mov	dword ptr [bp-116],eax
   ;	
   ;		 		  j++;
   ;	
	?debug	L 919
	inc	word ptr [bp-2]
	?debug	L 914
	inc	cx
@6@16:
	cmp	cx,29
	jle	short @6@12
	?debug	L 910
	add	word ptr [bp-182],4
	inc	word ptr [bp-144]
@6@19:
	cmp	word ptr [bp-144],10
	jle	@6@11
	?debug	L 908
	inc	word ptr [bp-142]
@6@21:
	cmp	word ptr [bp-142],5
	jle	@6@9
   ;	
   ;		 	  }
   ;		   }
   ;		 }
   ;	  parity_check(); // check the parity of the 1500 bit message
   ;	
	?debug	L 923
	call	far ptr @parity_check$qv
   ;	
   ;	  chan[ch].word_error[0]=p_error[1];
   ;	
	?debug	L 924
	mov	al,byte ptr [bp+8]
	cbw	
	imul	ax,ax,1738
	mov	dx,seg _chan
	mov	bx,seg _p_error
	mov	es,bx
	mov	bx,word ptr es:_p_error+2
	mov	es,dx
	xchg	bx,ax
	mov	word ptr es:_chan[bx+1522],ax
   ;	
   ;	  chan[ch].word_error[1]=p_error[2];
   ;	
	?debug	L 925
	mov	al,byte ptr [bp+8]
	cbw	
	imul	ax,ax,1738
	mov	dx,seg _chan
	mov	bx,seg _p_error
	mov	es,bx
	mov	bx,word ptr es:_p_error+4
	mov	es,dx
	xchg	bx,ax
	mov	word ptr es:_chan[bx+1524],ax
   ;	
   ;	  chan[ch].word_error[2]=p_error[3];
   ;	
	?debug	L 926
	mov	al,byte ptr [bp+8]
	cbw	
	imul	ax,ax,1738
	mov	dx,seg _chan
	mov	bx,seg _p_error
	mov	es,bx
	mov	bx,word ptr es:_p_error+6
	mov	es,dx
	xchg	bx,ax
	mov	word ptr es:_chan[bx+1526],ax
   ;	
   ;	  chan[ch].word_error[3]=p_error[4];
   ;	
	?debug	L 927
	mov	al,byte ptr [bp+8]
	cbw	
	imul	ax,ax,1738
	mov	dx,seg _chan
	mov	bx,seg _p_error
	mov	es,bx
	mov	bx,word ptr es:_p_error+8
	mov	es,dx
	xchg	bx,ax
	mov	word ptr es:_chan[bx+1528],ax
   ;	
   ;	  chan[ch].word_error[4]=p_error[5];
   ;	
	?debug	L 928
	mov	al,byte ptr [bp+8]
	cbw	
	imul	ax,ax,1738
	mov	dx,seg _chan
	mov	bx,seg _p_error
	mov	es,bx
	mov	bx,word ptr es:_p_error+10
	mov	es,dx
	xchg	bx,ax
	mov	word ptr es:_chan[bx+1530],ax
   ;	
   ;	//
   ;	//   EPHEMERIS DECODE subframes 1, 2, 3
   ;	//
   ;	//  subframe 1
   ;	//
   ;	//   check parity of first 3 subframes, since it is a circular register
   ;	//   we may have over written the first few bits so allow for word 1 of
   ;	//   subframe 1 to have a problem
   ;	//
   ;	
   ;	  if ((p_error[1]==0 || p_error[1]==0x200) && p_error[2]==0 && p_error[3]==0)
   ;	
	?debug	L 939
	mov	ax,seg _p_error
	mov	es,ax
	cmp	word ptr es:_p_error+2,0
	je	short @6@24
	mov	ax,seg _p_error
	mov	es,ax
	cmp	word ptr es:_p_error+2,512
	jne	@6@46
@6@24:
	mov	ax,seg _p_error
	mov	es,ax
	cmp	word ptr es:_p_error+4,0
	jne	@6@46
	mov	ax,seg _p_error
	mov	es,ax
	cmp	word ptr es:_p_error+6,0
	jne	@6@46
   ;	
   ;	  {
   ;			iodc=int(((sf[1][3] & 0x3) <<8 ) | ((sf[1][8] & 0xFF0000L) >>16));
   ;	
	?debug	L 941
	mov	ax,seg _sf
	mov	es,ax
	mov	eax,dword ptr es:_sf+76
	and	eax,large 000FF0000h
	shr	eax,16
	mov	dx,seg _sf
	mov	es,dx
	mov	dx,word ptr es:_sf+56
	and	dx,3
	shl	dx,8
	or	ax,dx
	mov	word ptr [bp-34],ax
   ;	
   ;			iode=int(sf[2][3]  >> 16);
   ;	
	?debug	L 942
	mov	ax,seg _sf
	mov	es,ax
	mov	eax,dword ptr es:_sf+100
	shr	eax,16
	mov	word ptr [bp-42],ax
   ;	
   ;			idoe=int(sf[3][10] >> 16);
   ;	
	?debug	L 943
	mov	ax,seg _sf
	mov	es,ax
	mov	eax,dword ptr es:_sf+172
	shr	eax,16
	mov	word ptr [bp-60],ax
   ;	
   ;	//      fprintf(kalm,"prn=%d iodc=%d, iode=%d,idoe=%d\n",prn,iodc,iode,idoe);
   ;	//      fprintf(kalm," eph.iode=%d, eph.iodc=%d\n",gps_eph[prn].iode,gps_eph[prn].iodc);
   ;	// if both copies of iode agree and we have a new iode or new iodc then process the ephemeris
   ;			if (iode==idoe && ((iode!=gps_eph[prn].iode) || (iodc!=gps_eph[prn].iodc)))
   ;	
	?debug	L 947
	mov	ax,word ptr [bp-42]
	cmp	ax,word ptr [bp-60]
	jne	@6@46
	mov	al,byte ptr [bp+6]
	cbw	
	imul	ax,ax,196
	mov	dx,seg _gps_eph
	mov	bx,ax
	mov	es,dx
	mov	ax,word ptr es:_gps_eph[bx]
	cmp	ax,word ptr [bp-42]
	jne	short @6@29
	mov	al,byte ptr [bp+6]
	cbw	
	imul	ax,ax,196
	mov	dx,seg _gps_eph
	mov	bx,ax
	mov	es,dx
	mov	ax,word ptr es:_gps_eph[bx+2]
	cmp	ax,word ptr [bp-34]
	je	@6@46
@6@29:
   ;	
   ;			{
   ;	
   ;				iweek= int(sf[1][3] >> 14);
   ;	
	?debug	L 950
	mov	ax,seg _sf
	mov	es,ax
	mov	eax,dword ptr es:_sf+56
	mov	dword ptr [bp-188],eax
	shr	eax,14
	mov	word ptr [bp-28],ax
   ;	
   ;	//			icapl2=( sf[1][3] & 0x3000 ) >> 12;
   ;				iura=int(( sf[1][3] & 0xF00 ) >> 8);
   ;	
	?debug	L 952
	mov	eax,dword ptr [bp-188]
	a