gpsfuncs.asm

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

	.386p
	.387
	ifndef	??version
?debug	macro
	endm
publicdll macro	name
	public	name
	endm
$comm	macro	name,dist,size,count
	comm	dist name:BYTE:count*size
	endm
	else
$comm	macro	name,dist,size,count
	comm	dist name[size]:BYTE:count
	endm
	endif
	?debug	V 301h
	?debug	S "gpsfuncs.cpp"
	?debug	C E9639F2A330C67707366756E63732E637070
	?debug	C E940287922135C4243355C494E434C5544455C54494D452E48
	?debug	C E940287922145C4243355C494E434C5544455C5F646566732E68
	?debug	C E940287922145C4243355C494E434C5544455C535444494F2E48
	?debug	C E940287922155C4243355C494E434C5544455C5F6E66696C652E68
	?debug	C E940287922145C4243355C494E434C5544455C5F6E756C6C2E68
	?debug	C E940287922155C4243355C494E434C5544455C5354444C49422E48
	?debug	C E940287922145C4243355C494E434C5544455C434F4E494F2E48
	?debug	C E940287922135C4243355C494E434C5544455C4D4154482E48
	?debug	C E940287922155C4243355C494E434C5544455C7374646465662E68
	?debug	C E940287922155C4243355C494E434C5544455C535452494E472E48
	?debug	C E940287922115C4243355C494E434C5544455C494F2E48
	?debug	C E940287922125C4243355C494E434C5544455C444F532E48
	?debug	C E9D28BE22E0A434D4154524958332E48
	?debug	C E940287922145C4243355C494E434C5544455C737464696F2E68
	?debug	C E940287922155C4243355C494E434C5544455C7374646C69622E68
	?debug	C E940287922175C4243355C494E434C5544455C696F73747265616D+
	?debug	C 2E68
	?debug	C E940287922165C4243355C494E434C5544455C6673747265616D2E+
	?debug	C 68
	?debug	C E940287922165C4243355C494E434C5544455C696F6D616E69702E+
	?debug	C 68
	?debug	C E940287922155C4243355C494E434C5544455C737472696E672E68
	?debug	C E940287922135C4243355C494E434C5544455C6D6174682E68
	?debug	C E940287922155C4243355C494E434C5544455C6D616C6C6F632E68
	?debug	C E940287922145C4243355C494E434C5544455C616C6C6F632E68
	?debug	C E9A161942F084750323032312E48
	?debug	C E93CA0263108434F4E5354532E48
GPSFUNCS_TEXT	segment byte public use16 'CODE'
GPSFUNCS_TEXT	ends
DGROUP	group	_DATA,_BSS
	assume	cs:GPSFUNCS_TEXT,ds:DGROUP
_DATA	segment word public use16 'DATA'
d@	label	byte
d@w	label	word
_DATA	ends
_BSS	segment word public use16 'BSS'
b@	label	byte
b@w	label	word
_BSS	ends
_DATA	segment word public use16 'DATA'
_pi	label	qword
	db	40
	db	45
	db	68
	db	84
	db	251
	db	33
	db	9
	db	64
_r_to_d	label	qword
	db	248
	db	193
	db	99
	db	26
	db	220
	db	165
	db	76
	db	64
_c	label	qword
	db	0
	db	0
	db	0
	db	74
	db	120
	db	222
	db	177
	db	65
_omegae	label	qword
	db	91
	db	141
	db	203
	db	215
	db	167
	db	29
	db	19
	db	63
_lambda	label	qword
	db	153
	db	230
	db	167
	db	6
	db	139
	db	91
	db	200
	db	63
	?debug	C E91C8A473109535452554354532E48
	?debug	C E98D961A3309474C4F42414C532E48
	?debug	C E96397E3320A47505346554E43532E48
_c_2p12	label	qword
	db	0
	db	0
	db	0
	db	0
	db	0
	db	0
	db	176
	db	64
_c_2p4	label	qword
	db	0
	db	0
	db	0
	db	0
	db	0
	db	0
	db	48
	db	64
_c_2m5	label	qword
	db	0
	db	0
	db	0
	db	0
	db	0
	db	0
	db	160
	db	63
_c_2m11	label	qword
	db	0
	db	0
	db	0
	db	0
	db	0
	db	0
	db	64
	db	63
_c_2m19	label	qword
	db	0
	db	0
	db	0
	db	0
	db	0
	db	0
	db	192
	db	62
_c_2m20	label	qword
	db	0
	db	0
	db	0
	db	0
	db	0
	db	0
	db	176
	db	62
_c_2m21	label	qword
	db	0
	db	0
	db	0
	db	0
	db	0
	db	0
	db	160
	db	62
_c_2m23	label	qword
	db	237
	db	255
	db	255
	db	255
	db	255
	db	255
	db	127
	db	62
_c_2m24	label	qword
	db	252
	db	255
	db	255
	db	255
	db	255
	db	255
	db	111
	db	62
_c_2m27	label	qword
	db	2
	db	0
	db	0
	db	0
	db	0
	db	0
	db	64
	db	62
_c_2m29	label	qword
	db	8
	db	0
	db	0
	db	0
	db	0
	db	0
	db	32
	db	62
_c_2m30	label	qword
	db	2
	db	0
	db	0
	db	0
	db	0
	db	0
	db	16
	db	62
_c_2m31	label	qword
	db	251
	db	255
	db	255
	db	255
	db	255
	db	255
	db	255
	db	61
_c_2m33	label	qword
	db	7
	db	0
	db	0
	db	0
	db	0
	db	0
	db	224
	db	61
_c_2m38	label	qword
	db	248
	db	255
	db	255
	db	255
	db	255
	db	255
	db	143
	db	61
_c_2m43	label	qword
	db	254
	db	255
	db	255
	db	255
	db	255
	db	255
	db	63
	db	61
_c_2m50	label	qword
	db	9
	db	251
	db	255
	db	255
	db	255
	db	255
	db	207
	db	60
_c_2m55	label	qword
	db	252
	db	255
	db	255
	db	255
	db	255
	db	255
	db	127
	db	60
_a	label	qword
	db	0
	db	0
	db	0
	db	64
	db	166
	db	84
	db	88
	db	65
_b	label	qword
	db	117
	db	147
	db	24
	db	20
	db	196
	db	63
	db	88
	db	65
_DATA	ends
GPSFUNCS_TEXT	segment byte public use16 'CODE'
	assume	cs:GPSFUNCS_TEXT,ds:DGROUP
@satfind$qc	proc	far
   ;	
   ;	satvis satfind(char i)
   ;	
	?debug	L 456
	?debug	B
	push	bp
	mov	bp,sp
	sub	sp,254
	push	si
	push	di
	?debug	C E60169020A0A000000
	?debug	B
	cmp	word ptr __stklen,sp
	ja	short @1@3
	call	far ptr F_OVERFLOW@
@1@3:
   ;	
   ;	{
   ;		float tdot,az;
   ;	   float satang,alm_time,almanac_date;
   ;	   double range1,range2,xls,yls,zls,xaz,yaz;
   ;	   long  jd_yr;
   ;	   ecef gpspos1,gpspos2,north,east,up;
   ;	   satvis result;
   ;	   int  jd_m;
   ;	   struct tm *gmt;
   ;	   double time_s;
   ;	/*
   ;	      INITIALIZE ALL THE CONSTANTS
   ;	*/
   ;	//	gotoxy(1,24);
   ;	//	printf("->satfind");
   ;		putenv(tzstr);
   ;	
	?debug	L 472
	push	seg _tzstr
	push	offset _tzstr
	call	far ptr _putenv
	add	sp,4
   ;	
   ;		tzset();
   ;	
	?debug	L 473
	call	far ptr _tzset
   ;	
   ;	//   thetime=time(NULL);
   ;		gmt=gmtime(&thetime);
   ;	
	?debug	L 475
	push	seg _thetime
	push	offset _thetime
	call	far ptr _gmtime
	add	sp,4
	mov	word ptr [bp-82],dx
	mov	word ptr [bp-84],ax
   ;	
   ;	// set up the correct time
   ;		if (gmt->tm_mon <= 1)
   ;	
	?debug	L 477
	les	bx,dword ptr [bp-84]
	cmp	word ptr es:[bx+8],1
	jg	short @1@5
   ;	
   ;		{
   ;		  jd_yr =365.25*(gmt->tm_year-1.+1900.);
   ;	
	?debug	L 479
	mov	ax,word ptr es:[bx+10]
	mov	word ptr [bp-96],ax
	fild	word ptr [bp-96]
	fld1	
	fsub	
	fadd	dword ptr DGROUP:s@
	fmul	dword ptr DGROUP:s@+4
	call	far ptr F_FTOL@
	shl	eax,16
	shrd	eax,edx,16
	mov	dword ptr [bp-80],eax
   ;	
   ;		  jd_m  =30.6001*(gmt->tm_mon+14.);
   ;	
	?debug	L 480
	les	bx,dword ptr [bp-84]
	mov	ax,word ptr es:[bx+8]
	mov	word ptr [bp-96],ax
	fild	word ptr [bp-96]
	fadd	dword ptr DGROUP:s@+8
	jmp	short @1@6
@1@5:
   ;	
   ;		}
   ;		else
   ;		{
   ;		  jd_yr=365.25*(gmt->tm_year+1900.);
   ;	
	?debug	L 484
	les	bx,dword ptr [bp-84]
	mov	ax,word ptr es:[bx+10]
	mov	word ptr [bp-96],ax
	fild	word ptr [bp-96]
	fadd	dword ptr DGROUP:s@
	fmul	dword ptr DGROUP:s@+4
	call	far ptr F_FTOL@
	shl	eax,16
	shrd	eax,edx,16
	mov	dword ptr [bp-80],eax
   ;	
   ;		  jd_m =30.6001*(gmt->tm_mon+2.);
   ;	
	?debug	L 485
	les	bx,dword ptr [bp-84]
	mov	ax,word ptr es:[bx+8]
	mov	word ptr [bp-96],ax
	fild	word ptr [bp-96]
	fadd	dword ptr DGROUP:s@+20
@1@6:
	fmul	qword ptr DGROUP:s@+12
	call	far ptr F_FTOL@
	mov	dx,ax
   ;	
   ;		}
   ;		time_s=gmt->tm_min/1440.+gmt->tm_sec/86400.+1720981.5+gmt->tm_hour/24.
   ;	
	?debug	L 487
   ;	
   ;		 +jd_yr+jd_m+gmt->tm_mday;
   ;	
	?debug	L 488
	les	bx,dword ptr [bp-84]
	mov	ax,word ptr es:[bx+2]
	mov	word ptr [bp-96],ax
	fild	word ptr [bp-96]
	fdiv	dword ptr DGROUP:s@+24
	mov	ax,word ptr es:[bx]
	mov	word ptr [bp-96],ax
	fild	word ptr [bp-96]
	fdiv	dword ptr DGROUP:s@+28
	fadd	
	fadd	dword ptr DGROUP:s@+32
	mov	ax,word ptr es:[bx+4]
	mov	word ptr [bp-96],ax
	fild	word ptr [bp-96]
	fdiv	dword ptr DGROUP:s@+36
	fadd	
	mov	eax,dword ptr [bp-80]
	mov	dword ptr [bp-96],eax
	fild	dword ptr [bp-96]
	fadd	
	mov	word ptr [bp-96],dx
	fild	word ptr [bp-96]
	fadd	
	mov	ax,word ptr es:[bx+6]
	mov	word ptr [bp-96],ax
	fild	word ptr [bp-96]
	fadd	
	fstp	qword ptr [bp-92]
   ;	
   ;		gps_week=int((time_s-2444244.5)/7.);
   ;	
	?debug	L 489
	fld	qword ptr [bp-92]
	fsub	dword ptr DGROUP:s@+40
	fdiv	dword ptr DGROUP:s@+44
	call	far ptr F_FTOL@
	mov	dx,seg _gps_week
	mov	es,dx
	mov	word ptr es:_gps_week,ax
   ;	
   ;		almanac_date=gps_alm[i].week*7.0+2444244.5;
   ;	
	?debug	L 490
	mov	al,byte ptr [bp+10]
	cbw	
	imul	ax,ax,74
	mov	dx,seg _gps_alm
	mov	bx,ax
	mov	es,dx
	mov	ax,word ptr es:_gps_alm[bx+70]
	mov	word ptr [bp-96],ax
	fild	word ptr [bp-96]
	fmul	dword ptr DGROUP:s@+44
	fadd	dword ptr DGROUP:s@+40
	fstp	dword ptr [bp-20]
   ;	
   ;	   if (gps_week-gps_alm[i].week>512) almanac_date+=1024*7.0;
   ;	
	?debug	L 491
	fwait	
	mov	al,byte ptr [bp+10]
	cbw	
	imul	ax,ax,74
	mov	dx,seg _gps_alm
	mov	bx,seg _gps_week
	mov	es,bx
	mov	bx,word ptr es:_gps_week
	mov	word ptr [bp-100],bx
	mov	es,dx
	xchg	bx,ax
	sub	ax,word ptr es:_gps_alm[bx+70]
	cmp	ax,512
	jle	short @1@9
	fld	dword ptr [bp-20]
	fadd	dword ptr DGROUP:s@+48
	fstp	dword ptr [bp-20]
	fwait	
@1@9:
   ;	
   ;	   alm_time=(time_s-almanac_date)*86400.;
   ;	
	?debug	L 492
	fld	dword ptr [bp-20]
	fsubr	qword ptr [bp-92]
	fmul	dword ptr DGROUP:s@+28
	fstp	dword ptr [bp-16]
   ;	
   ;	   clock_tow=(time_s-gps_week*7.-2444244.5)*86400.;
   ;	
	?debug	L 493
	fwait	
	mov	ax,word ptr [bp-100]
	mov	word ptr [bp-96],ax
	fild	word ptr [bp-96]
	fmul	dword ptr DGROUP:s@+44
	fsubr	qword ptr [bp-92]
	fsub	dword ptr DGROUP:s@+40
	fmul	dword ptr DGROUP:s@+28
	call	far ptr F_FTOL@
	shl	eax,16
	shrd	eax,edx,16
	mov	dx,seg _clock_tow
	mov	es,dx
	mov	dword ptr es:_clock_tow,eax
   ;	
   ;	/*
   ;	      CALCULATE THE POSITION OF THE SATELLITES
   ;	*/
   ;	   if (gps_alm[i].inc > 0.0 && i>0)
   ;	
	?debug	L 497
	mov	al,byte ptr [bp+10]
	cbw	
	mov	word ptr [bp-98],ax
	imul	ax,ax,74
	mov	dx,seg _gps_alm
	mov	bx,ax
	mov	es,dx
	fld	dword ptr es:_gps_alm[bx+8]
	fldz	
	fcompp
	fstsw	ax
	sahf	
	jae	@1@22
	cmp	word ptr [bp-98],0
	jle	@1@22
   ;	
   ;	      {
   ;		gpspos1=satpos_almanac(alm_time,i);
   ;	
	?debug	L 499
	mov	al,byte ptr [bp+10]
	push	ax
	push	dword ptr [bp-16]
	push	ss
	lea	ax,word ptr [bp-134]
	push	ax
	call	far ptr @satpos_almanac$qfc
	add	sp,10
   ;	
   ;		gpspos2=satpos_almanac(alm_time+1.0,i);
   ;	
	?debug	L 500
	mov	al,byte ptr [bp+10]
	push	ax
	fld	dword ptr [bp-16]
	fld1	
	fadd	
	sub	sp,4
	fstp	dword ptr [bp-264]
	push	ss
	fwait	
	lea	ax,word ptr [bp-158]
	push	ax
	call	far ptr @satpos_almanac$qfc
	add	sp,10
   ;	
   ;	/*
   ;	      CALCULATE THE POSITION OF THE RECEIVER
   ;	*/
   ;		rec_pos_xyz=llh_to_ecef(current_loc);
   ;	
	?debug	L 504
	mov	ax,offset _current_loc
	mov	dx,seg _current_loc
	mov	cx,24
	call	far ptr F_SPUSH@
	push	seg _rec_pos_xyz
	push	offset _rec_pos_xyz
	call	far ptr @llh_to_ecef$q3llh
	add	sp,28
   ;	
   ;		north.x=-cos(current_loc.lon)*sin(current_loc.lat);
   ;	
	?debug	L 505
	mov	ax,seg _current_loc
	mov	es,ax
	fld	qword ptr es:_current_loc+8
	sub	sp,8
	fstp	qword ptr [bp-266]
	fwait	
	call	far ptr _cos
	add	sp,8
	fchs	
	fstp	tbyte ptr [bp-110]
	mov	ax,seg _current_loc
	mov	es,ax
	fld	qword ptr es:_current_loc
	sub	sp,8
	fstp	qword ptr [bp-266]
	fwait	
	call	far ptr _sin
	add	sp,8
	fld	tbyte ptr [bp-110]
	fmul	
	fstp	qword ptr [bp-182]
   ;	
   ;		north.y=-sin(current_loc.lon)*sin(current_loc.lat);
   ;	
	?debug	L 506
	mov	ax,seg _current_loc
	mov	es,ax
	fld	qword ptr es:_current_loc+8
	sub	sp,8
	fstp	qword ptr [bp-266]
	fwait	
	call	far ptr _sin
	add	sp,8
	fchs	
	fstp	tbyte ptr [bp-110]
	mov	ax,seg _current_loc
	mov	es,ax
	fld	qword ptr es:_current_loc
	sub	sp,8
	fstp	qword ptr [bp-266]
	fwait	
	call	far ptr _sin
	add	sp,8
	fld	tbyte ptr [bp-110]
	fmul	
	fstp	qword ptr [bp-174]
   ;	
   ;	   north.z= cos(current_loc.lat);
   ;	
	?debug	L 507
	mov	ax,seg _current_loc
	mov	es,ax
	fld	qword ptr es:_current_loc
	sub	sp,8
	fstp	qword ptr [bp-266]
	fwait	
	call	far ptr _cos
	add	sp,8
	fstp	qword ptr [bp-166]
   ;	
   ;	   east.x=-sin(current_loc.lon);
   ;	
	?debug	L 508
	mov	ax,seg _current_loc
	mov	es,ax
	fld	qword ptr es:_current_loc+8
	sub	sp,8
	fstp	qword ptr [bp-266]
	fwait	
	call	far ptr _sin
	add	sp,8
	fchs	
	fstp	qword ptr [bp-206]
   ;	
   ;	   east.y= cos(current_loc.lon);
   ;	
	?debug	L 509
	mov	ax,seg _current_loc
	mov	es,ax
	fld	qword ptr es:_current_loc+8
	sub	sp,8
	fstp	qword ptr [bp-266]
	fwait	
	call	far ptr _cos
	add	sp,8
	fstp	qword ptr [bp-198]
   ;	
   ;	//   east.z=0.0;
   ;	   up.x=cos(current_loc.lon)*cos(current_loc.lat);
   ;