From Michael Lum:

This patch implements parameter dissection for about 1/2 to 2/3 of the messages in IS-801.

Built and tested against the latest source as of Friday April 13th 2007.

svn path=/trunk/; revision=21463

1 files changed, 1872 insertions, 214 deletions

diff --git a/epan/dissectors/packet-ansi_801.c b/epan/dissectors/packet-ansi_801.c
index 15c0527e69..f2d12960fc 100644
--- a/epan/dissectors/packet-ansi_801.c
+++ b/epan/dissectors/packet-ansi_801.c
@@ -9,6 +9,8 @@
  *
  * Copyright 2004, Michael Lum <mlum [AT] telostech.com>
  * In association with Telos Technology Inc.
+ * Copyright 2007, Michael Lum <michael.lum [AT] utstar.com>
+ * In association with UTStarcom Inc.
  *
  * $Id$
  *
@@ -80,6 +82,93 @@ static proto_tree *g_tree;
 
 /* FUNCTIONS */
 
+static const guint8 bit_mask[] = {
+    0x01,
+    0x03,
+    0x07,
+    0x0f,
+    0x1f,
+    0x3f,
+    0x7f,
+    0xff
+};
+
+guint64
+tvb_get_bits(tvbuff_t *tvb, guint32 *offset_p, guint8 *bit_offset_p, guint8 num_bits)
+{
+    guint64	bits;
+    guint64	temp_octs;
+    guint8	num_octs;
+    guint8	shift_bits;
+    guint8	remaining_bits;
+
+    if (num_bits <= *bit_offset_p)
+    {
+	shift_bits = (*bit_offset_p) - num_bits;
+
+	bits = (tvb_get_guint8(tvb, *offset_p) & bit_mask[(*bit_offset_p)-1]) >> shift_bits;
+
+	if (shift_bits == 0)
+	{
+	    /* consumed everything in octet */
+	    *offset_p += 1;
+	}
+	else
+	{
+	    /* consumed subset of bits available in current octet */
+	    *bit_offset_p -= shift_bits;
+	}
+
+	return(bits);
+    }
+
+    shift_bits = (num_bits - *bit_offset_p);
+
+    bits = (tvb_get_guint8(tvb, *offset_p) & bit_mask[(*bit_offset_p)-1]) << shift_bits;
+
+    num_octs = (shift_bits / 8) + 1;
+    remaining_bits = shift_bits % 8;
+
+    switch (num_octs)
+    {
+    case 1:
+	bits |= tvb_get_guint8(tvb, (*offset_p)+1) >> (8 - remaining_bits);
+	break;
+    case 2:
+	bits |= tvb_get_ntohs(tvb, (*offset_p)+1) >> (8 - remaining_bits);
+	break;
+    case 3:
+	bits |= tvb_get_ntoh24(tvb, (*offset_p)+1) >> (8 - remaining_bits);
+	break;
+    case 4:
+	bits |= tvb_get_ntohl(tvb, (*offset_p)+1) >> (8 - remaining_bits);
+	break;
+    case 5:
+	temp_octs = tvb_get_ntohl(tvb, (*offset_p)+1) << 8;
+	temp_octs |= tvb_get_guint8(tvb, (*offset_p)+5);
+	bits |= temp_octs >> (8 - remaining_bits);
+	break;
+    case 6:
+	temp_octs = tvb_get_ntohl(tvb, (*offset_p)+1) << 16;
+	temp_octs |= tvb_get_ntohs(tvb, (*offset_p)+5);
+	bits |= temp_octs >> (8 - remaining_bits);
+	break;
+    case 7:
+	temp_octs = tvb_get_ntohl(tvb, (*offset_p)+1) << 24;
+	temp_octs |= tvb_get_ntoh24(tvb, (*offset_p)+5);
+	bits |= temp_octs >> (8 - remaining_bits);
+	break;
+    case 8:
+	bits |= tvb_get_ntoh64(tvb, (*offset_p)+1) >> (8 - remaining_bits);
+	break;
+    }
+
+    *offset_p += num_octs;
+    *bit_offset_p = 8 - remaining_bits;
+
+    return(bits);
+}
+
 /* PARAM FUNCTIONS */
 
 #define	EXTRANEOUS_DATA_CHECK(edc_len, edc_max_len) \
@@ -106,6 +195,80 @@ static proto_tree *g_tree;
     }
 
 
+/*
+ * Table 3.2-4 for PD_MSG_TYPE = '0000000'
+ */
+static const value_string for_req_type_strings[] = {
+    { 0,	"Reserved" },
+    { 2,	"Request MS Information" },
+    { 3,	"Request Autonomous Measurement Weighting Factors" },
+    { 4,	"Request Pseudorange Measurement" },
+    { 5,	"Request Pilot Phase Measurement" },
+    { 1,	"Request Location Response" },
+    { 6,	"Request Time Offset Measurement" },
+    { 7,	"Request Cancellation" },
+    { 0, NULL },
+};
+#define	NUM_FOR_REQ_TYPE (sizeof(for_req_type_strings)/sizeof(value_string))
+static gint ett_for_req_type[NUM_FOR_REQ_TYPE];
+
+static const value_string for_rsp_type_strings[] = {
+    { 0,	"Reject" },
+    { 2,	"Provide BS Capabilities" },
+    { 4,	"Provide GPS Acquisition Assistance" },
+    { 6,	"Provide GPS Location Assistance Spherical Coordinates" },
+    { 7,	"Provide GPS Location Assistance Cartesian Coordinates" },
+    { 5,	"Provide GPS Sensitivity Assistance" },
+    { 3,	"Provide Base Station Almanac" },
+    { 8,	"Provide GPS Almanac" },
+    { 9,	"Provide GPS Ephemeris" },
+    { 10,	"Provide GPS Navigation Message Bits" },
+    { 1,	"Provide Location Response" },
+    { 11,	"Provide GPS Almanac Correction" },
+    { 12,	"Provide GPS Satellite Health Information" },
+    { 0, NULL },
+};
+#define	NUM_FOR_RSP_TYPE (sizeof(for_rsp_type_strings)/sizeof(value_string))
+static gint ett_for_rsp_type[NUM_FOR_RSP_TYPE];
+
+
+static const value_string rev_rsp_type_strings[] = {
+    { 0,	"Reject" },
+    { 2,	"Provide MS Information" },
+    { 3,	"Provide Autonomous Measurement Weighting Factors" },
+    { 4,	"Provide Pseudorange Measurement" },
+    { 5,	"Provide Pilot Phase Measurement" },
+    { 1,	"Provide Location Response" },
+    { 6,	"Provide Time Offset Measurement" },
+    { 7,	"Provide Cancellation Acknowledgement" },
+    { 0, NULL },
+};
+#define	NUM_REV_RSP_TYPE (sizeof(rev_rsp_type_strings)/sizeof(value_string))
+static gint ett_rev_rsp_type[NUM_REV_RSP_TYPE];
+
+/*
+ * Table 2.2-5 for PD_MSG_TYPE = '0000000'
+ */
+static const value_string rev_req_type_strings[] = {
+    { 0,	"Reserved" },
+    { 2,	"Request BS Capabilities" },
+    { 4,	"Request GPS Acquisition Assistance" },
+    { 6,	"Request GPS Location Assistance" },
+    { 7,	"Reserved" },
+    { 5,	"Request GPS Sensitivity Assistance" },
+    { 3,	"Request Base Station Almanac" },
+    { 8,	"Request GPS Almanac" },
+    { 9,	"Request GPS Ephemeris" },
+    { 10,	"Request GPS Navigation Message Bits" },
+    { 1,	"Request Location Response" },
+    { 11,	"Request GPS Almanac Correction" },
+    { 12,	"Request GPS Satellite Health Information" },
+    { 0, NULL },
+};
+#define	NUM_REV_REQ_TYPE (sizeof(rev_req_type_strings)/sizeof(value_string))
+static gint ett_rev_req_type[NUM_REV_REQ_TYPE];
+
+
 static void
 for_req_pseudo_meas(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
 {
@@ -162,128 +325,1493 @@ for_req_pseudo_meas(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
     EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
 }
 
-static const value_string for_req_type_strings[] = {
-    { 0,	"Reserved" },
-    { 2,	"Request MS Information" },
-    { 3,	"Request Autonomous Measurement Weighting Factors" },
-    { 4,	"Request Pseudorange Measurement" },
-    { 5,	"Request Pilot Phase Measurement" },
-    { 1,	"Request Location Response" },
-    { 6,	"Request Time Offset Measurement" },
-    { 7,	"Request Cancellation" },
-    { 0, NULL },
-};
-#define	NUM_FOR_REQ_TYPE (sizeof(for_req_type_strings)/sizeof(value_string))
-static gint ett_for_req_type[NUM_FOR_REQ_TYPE];
+static void
+for_req_pilot_ph_meas(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint32	value;
+    guint32	saved_offset;
+
+    SHORT_DATA_CHECK(len, 3);
+
+    saved_offset = offset;
+
+    value = tvb_get_ntoh24(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value >> 16, 0xe0, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Preferred response quality, %u",
+	bigbuf,
+	(value & 0xe00000) >> 21);
+
+    other_decode_bitfield_value(bigbuf, value >> 16, 0x1f, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Number of fixes (MSB), %u",
+	bigbuf,
+	(value & 0x1fe000) >> 13);
+
+    other_decode_bitfield_value(bigbuf, value >> 8, 0xe0, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Number of fixes (LSB)",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value >> 8, 0x1f, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Time between fixes (MSB), %u",
+	bigbuf,
+	(value & 0x001fe0) >> 5);
+
+    other_decode_bitfield_value(bigbuf, value, 0xe0, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Time between fixes (LSB)",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x10, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Offset %srequested",
+	bigbuf,
+	(value & 0x10) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, value, 0x08, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Desired pilot phase resolution: at least %s PN chip resolution",
+	bigbuf,
+	(value & 0x08) ? "1/8th" : "1");
+
+    other_decode_bitfield_value(bigbuf, value, 0x07, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset += 3;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+for_req_loc_response(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint32	value;
+    guint32	saved_offset;
+
+    SHORT_DATA_CHECK(len, 3);
+
+    saved_offset = offset;
+
+    value = tvb_get_ntoh24(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value >> 16, 0xe0, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Preferred response quality, %u",
+	bigbuf,
+	(value & 0xe00000) >> 21);
+
+    other_decode_bitfield_value(bigbuf, value >> 16, 0x1f, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Number of fixes (MSB), %u",
+	bigbuf,
+	(value & 0x1fe000) >> 13);
+
+    other_decode_bitfield_value(bigbuf, value >> 8, 0xe0, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Number of fixes (LSB)",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value >> 8, 0x1f, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Time between fixes (MSB), %u",
+	bigbuf,
+	(value & 0x001fe0) >> 5);
+
+    other_decode_bitfield_value(bigbuf, value, 0xe0, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Time between fixes (LSB)",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x10, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Height information %srequested",
+	bigbuf,
+	(value & 0x10) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, value, 0x08, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Clock correction for GPS time %srequested",
+	bigbuf,
+	(value & 0x08) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, value, 0x04, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Velocity information %srequested",
+	bigbuf,
+	(value & 0x04) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, value, 0x03, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset += 3;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+for_req_time_off_meas(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint8	bit_mask;
+    guint32	saved_offset;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    saved_offset = offset;
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x80, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Use action time indicator",
+	bigbuf);
+
+    if (oct & 0x80)
+    {
+	other_decode_bitfield_value(bigbuf, oct, 0x7e, 8);
+	proto_tree_add_text(tree, tvb, offset, 1,
+	    "%s :  Action time, %u",
+	    bigbuf,
+	    (oct & 0x7e) >> 1);
+
+	bit_mask = 0x01;
+    }
+    else
+    {
+	bit_mask = 0x7f;
+    }
+
+    other_decode_bitfield_value(bigbuf, oct, bit_mask, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+for_req_cancel(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint32	saved_offset;
+    const gchar	*str = NULL;
+    gint	idx;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    saved_offset = offset;
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    str = match_strval_idx((oct & 0xf0) >> 4, for_req_type_strings, &idx);
+    if (str == NULL)
+    {
+	str = "Reserved";
+    }
+
+    other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Cancellation Type: (%u) %s",
+	bigbuf,
+	(oct & 0xf0) >> 4,
+	str);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x0f, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+for_reject(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint32	saved_offset;
+    const gchar	*str = NULL;
+    gint	idx;
+
+    saved_offset = offset;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    str = match_strval_idx((oct & 0xf0) >> 4, rev_req_type_strings, &idx);
+    if (str == NULL)
+    {
+	str = "Reserved";
+    }
+
+    other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reject request type: (%u) %s",
+	bigbuf,
+	(oct & 0xf0) >> 4,
+	str);
+
+    switch ((oct & 0x0e) >> 1)
+    {
+    case 0x00: str = "Capability not supported by the base station"; break;
+    case 0x01: str = "Capability normally supported by the base station but temporarily not available or not enabled"; break;
+    default: str = "Reserved"; break;
+    }
+
+    other_decode_bitfield_value(bigbuf, oct, 0x0e, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reject reason: %s",
+	bigbuf,
+	str);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x01, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+for_pr_bs_cap(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint32	saved_offset;
+
+    saved_offset = offset;
+
+    SHORT_DATA_CHECK(len, 2);
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, oct, 0xfc, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  BS_LS_REV",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x02, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  GPSC_ID: GPS capability indicator",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x01, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  AFLTC_ID: Advanced forward link trilateration capability indicator",
+	bigbuf);
+
+    offset++;
+
+    oct = tvb_get_guint8(tvb, offset);
+    if (oct == 0x00)
+    {
+	proto_tree_add_text(tree, tvb, offset, 1,
+	    "APDC_ID: Autonomous position determination capability indicator: None");
+    }
+    else
+    {
+	proto_tree_add_text(tree, tvb, offset, 1,
+	    "APDC_ID: Autonomous position determination capability indicator: Autonomous Location Technology Identifier %u",
+	    oct);
+    }
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+for_pr_gps_sense_ass(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint8	num_dr_p;
+    guint32	value;
+    guint32	saved_offset;
+
+    saved_offset = offset;
+
+    SHORT_DATA_CHECK(len, 4);
+
+    value = tvb_get_ntohs(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value, 0xffe0, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  REF_BIT_NUM: %u",
+	bigbuf,
+	(value & 0xffe0) >> 5);
+
+    num_dr_p = (value & 0x001e) >> 1;
+
+    other_decode_bitfield_value(bigbuf, value, 0x001e, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  NUM_DR_P: Number of data records in this part: %u",
+	bigbuf,
+	num_dr_p);
+
+    offset += 2;
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value, 0x0001, 16);
+    value = ((value & 0x0001) << 7) | ((oct & 0xfe) >> 1);
+
+    proto_tree_add_text(tree, tvb, offset - 2, 2,
+	"%s :  DR_SIZE: Data record size in 2-bit units (MSB): %u",
+	bigbuf,
+	value);
+
+    other_decode_bitfield_value(bigbuf, oct, 0xfe, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  DR_SIZE: (LSB)",
+	bigbuf);
+
+    value = oct;
+    offset++;
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value, 0x01, 8);
+    value = ((value & 0x0001) << 2) | ((oct & 0xc0) >> 6);
+
+    proto_tree_add_text(tree, tvb, offset - 1, 1,
+	"%s :  PART_NUM: The part number (MSB): %u",
+	bigbuf,
+	value);
+
+    other_decode_bitfield_value(bigbuf, oct, 0xc0, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  PART_NUM: (LSB)",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x38, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  TOTAL_PARTS: Total number of parts: %u",
+	bigbuf,
+	(oct & 0x38) >> 3);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x07, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Data records (MSB)",
+	bigbuf);
+
+    offset++;
+
+    proto_tree_add_text(tree, tvb, offset, (len - (offset - saved_offset)),
+	"%s :  Data records (LSB) + Reserved",
+	bigbuf);
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+for_pr_gps_almanac(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	num_sv;
+    guint32	value;
+    guint32	saved_offset;
+
+    saved_offset = offset;
+
+    SHORT_DATA_CHECK(len, 4);
+
+    value = tvb_get_ntohl(tvb, offset);
+    num_sv = (value & 0xfc000000) >> 26;
+
+    other_decode_bitfield_value(bigbuf, value, 0xfc000000, 32);
+    proto_tree_add_text(tree, tvb, offset, 4,
+	"%s :  NUM_SV_P: Number of satellites in this part: %u",
+	bigbuf,
+	num_sv);
+
+    other_decode_bitfield_value(bigbuf, value, 0x03fc0000, 32);
+    proto_tree_add_text(tree, tvb, offset, 4,
+	"%s :  WEEK_NUM: The GPS week number of the almanac: %u",
+	bigbuf,
+	(value & 0x03fc0000) >> 18);
+
+    other_decode_bitfield_value(bigbuf, value, 0x0003fc00, 32);
+    proto_tree_add_text(tree, tvb, offset, 4,
+	"%s :  TOA: The reference time of the almanac: %u",
+	bigbuf,
+	(value & 0x0003fc00) >> 10);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000003e0, 32);
+    proto_tree_add_text(tree, tvb, offset, 4,
+	"%s :  PART_NUM: The part number: %u",
+	bigbuf,
+	(value & 0x000003e0) >> 5);
+
+    other_decode_bitfield_value(bigbuf, value, 0x0000001f, 32);
+    proto_tree_add_text(tree, tvb, offset, 4,
+	"%s :  TOTAL_PARTS: The total number of parts: %u",
+	bigbuf,
+	(value & 0x0000001f));
+
+    offset += 4;
+
+    proto_tree_add_text(tree, tvb, offset, (len - (offset - saved_offset)),
+	"%u Data records + Reserved",
+	num_sv);
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+for_pr_gps_nav_msg_bits(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	num_sv;
+    guint32	value;
+    guint32	saved_offset;
+
+    saved_offset = offset;
+
+    SHORT_DATA_CHECK(len, 2);
+
+    value = tvb_get_ntohs(tvb, offset);
+    num_sv = (value & 0xfc00) >> 10;
+
+    other_decode_bitfield_value(bigbuf, value, 0xfc00, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  NUM_SV_P: Number of satellites in this part: %u",
+	bigbuf,
+	num_sv);
+
+    other_decode_bitfield_value(bigbuf, value, 0x03e0, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  PART_NUM: The part number: %u",
+	bigbuf,
+	(value & 0x03e0) >> 5);
+
+    other_decode_bitfield_value(bigbuf, value, 0x001f, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  TOTAL_PARTS: The total number of parts: %u",
+	bigbuf,
+	(value & 0x001f));
+
+    offset += 2;
+
+    proto_tree_add_text(tree, tvb, offset, (len - (offset - saved_offset)),
+	"%u SUBF_4_5_INCL ... Data records + Reserved",
+	num_sv);
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+/*
+ * shared for both forward/reverse directions
+ */
+static void
+pr_loc_response(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint8	bit_mask;
+    guint8	bit_offset;
+    guint32	fix_type;
+    guint32	value;
+    guint64	temp_int;
+    guint32	new_offset;
+    guint32	saved_offset;
+    const gchar	*str = NULL;
+
+    saved_offset = offset;
+
+    SHORT_DATA_CHECK(len, 11);
+
+    value = tvb_get_ntohs(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value, 0xfffc, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  TIME_REF_CDMA: CDMA system time at the time the solution is valid.",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x0003, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  LAT (MSB)",
+	bigbuf);
+
+    offset += 2;
+    value = tvb_get_ntoh24(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value, 0xfffffe, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LAT (LSB)",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000001, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LONG (MSB)",
+	bigbuf);
+
+    offset += 3;
+    value = tvb_get_ntoh24(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value, 0xffffff, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LONG",
+	bigbuf);
+
+    offset += 3;
+    value = tvb_get_ntohs(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value, 0x8000, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  LONG (LSB)",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x7800, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  LOC_UNCRTNTY_ANG",
+	bigbuf);
+
+    switch ((value & 0x07c0) >> 6)
+    {
+    case 0x00: str = "0.5"; break;
+    case 0x01: str = "0.75"; break;
+    case 0x02: str = "1"; break;
+    case 0x03: str = "1.5"; break;
+    case 0x04: str = "2"; break;
+    case 0x05: str = "3"; break;
+    case 0x06: str = "4"; break;
+    case 0x07: str = "6"; break;
+    case 0x08: str = "8"; break;
+    case 0x09: str = "12"; break;
+    case 0x0a: str = "16"; break;
+    case 0x0b: str = "24"; break;
+    case 0x0c: str = "32"; break;
+    case 0x0d: str = "48"; break;
+    case 0x0e: str = "64"; break;
+    case 0x0f: str = "96"; break;
+    case 0x10: str = "128"; break;
+    case 0x11: str = "192"; break;
+    case 0x12: str = "256"; break;
+    case 0x13: str = "384"; break;
+    case 0x14: str = "512"; break;
+    case 0x15: str = "768"; break;
+    case 0x16: str = "1,024"; break;
+    case 0x17: str = "1,536"; break;
+    case 0x18: str = "2,048"; break;
+    case 0x19: str = "3,072"; break;
+    case 0x1a: str = "4,096"; break;
+    case 0x1b: str = "6,144"; break;
+    case 0x1c: str = "8,192"; break;
+    case 0x1d: str = "12,288"; break;
+    case 0x1e: str = ">12,288"; break;
+    case 0x1f: str = "Not computable"; break;
+    }
+
+    other_decode_bitfield_value(bigbuf, value, 0x07c0, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  LOC_UNCRTNTY_A: Standard deviation of axis along angle specified for position uncertainty (meters): %s",
+	bigbuf,
+	str);
+
+    switch ((value & 0x003e) >> 1)
+    {
+    case 0x00: str = "0.5"; break;
+    case 0x01: str = "0.75"; break;
+    case 0x02: str = "1"; break;
+    case 0x03: str = "1.5"; break;
+    case 0x04: str = "2"; break;
+    case 0x05: str = "3"; break;
+    case 0x06: str = "4"; break;
+    case 0x07: str = "6"; break;
+    case 0x08: str = "8"; break;
+    case 0x09: str = "12"; break;
+    case 0x0a: str = "16"; break;
+    case 0x0b: str = "24"; break;
+    case 0x0c: str = "32"; break;
+    case 0x0d: str = "48"; break;
+    case 0x0e: str = "64"; break;
+    case 0x0f: str = "96"; break;
+    case 0x10: str = "128"; break;
+    case 0x11: str = "192"; break;
+    case 0x12: str = "256"; break;
+    case 0x13: str = "384"; break;
+    case 0x14: str = "512"; break;
+    case 0x15: str = "768"; break;
+    case 0x16: str = "1,024"; break;
+    case 0x17: str = "1,536"; break;
+    case 0x18: str = "2,048"; break;
+    case 0x19: str = "3,072"; break;
+    case 0x1a: str = "4,096"; break;
+    case 0x1b: str = "6,144"; break;
+    case 0x1c: str = "8,192"; break;
+    case 0x1d: str = "12,288"; break;
+    case 0x1e: str = ">12,288"; break;
+    case 0x1f: str = "Not computable"; break;
+    }
+
+    other_decode_bitfield_value(bigbuf, value, 0x003e, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  LOC_UNCRTNTY_P: Standard deviation of axis perpindicular to angle specified for position uncertainty (meters): %s",
+	bigbuf,
+	str);
+
+    fix_type = value & 0x0001;
+
+    other_decode_bitfield_value(bigbuf, value, 0x0001, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  FIX_TYPE: %s",
+	bigbuf,
+	fix_type ? "3D" : "2D");
+
+    offset += 2;
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x80, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  VELOCITY_INCL: Velocity information %sincluded",
+	bigbuf,
+	(oct & 0x80) ? "" : "not ");
+
+    if (oct & 0x80)
+    {
+	value = (oct & 0x7f) << 2;
+
+	other_decode_bitfield_value(bigbuf, oct, 0x7f, 8);
+
+	offset++;
+	oct = tvb_get_guint8(tvb, offset);
+	value |= ((oct & 0xc0) >> 6);
+
+	proto_tree_add_text(tree, tvb, offset-1, 1,
+	    "%s :  VELOCITY_HOR: Horizontal velocity magnitude (MSB) (%u)",
+	    bigbuf,
+	    value);
+
+	other_decode_bitfield_value(bigbuf, oct, 0xc0, 8);
+	proto_tree_add_text(tree, tvb, offset, 1,
+	    "%s :  VELOCITY_HOR: Horizontal velocity magnitude (LSB)",
+	    bigbuf);
+
+	value = (oct & 0x3f) << 4;
+
+	other_decode_bitfield_value(bigbuf, oct, 0x3f, 8);
+
+	offset++;
+	oct = tvb_get_guint8(tvb, offset);
+	value |= ((oct & 0xf0) >> 4);
+
+	proto_tree_add_text(tree, tvb, offset-1, 1,
+	    "%s :  HEADING: (MSB) (%u)",
+	    bigbuf,
+	    value);
+
+	other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
+	proto_tree_add_text(tree, tvb, offset, 1,
+	    "%s :  HEADING: (LSB)",
+	    bigbuf);
+
+	if (fix_type)
+	{
+	    value = (oct & 0x0f) << 4;
+
+	    other_decode_bitfield_value(bigbuf, oct, 0x0f, 8);
+
+	    offset++;
+	    oct = tvb_get_guint8(tvb, offset);
+	    value |= ((oct & 0xf0) >> 4);
+
+	    proto_tree_add_text(tree, tvb, offset-1, 1,
+		"%s :  VELOCITY_VER: Vertical velocity magnitude (MSB) (%u)",
+		bigbuf,
+		value);
+
+	    other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
+	    proto_tree_add_text(tree, tvb, offset, 1,
+		"%s :  VELOCITY_VER: Vertical velocity magnitude (LSB)",
+		bigbuf);
+	}
+
+	/*
+	 * in either case (fix_type) we have the low 4 bits
+	 * left over from the octet pointed to by 'offset'
+	 */
+	bit_mask = 0x08;
+	bit_offset = 3;
+    }
+    else
+    {
+	/*
+	 * no code here just co-located comments for bit mask
+	 */
+	bit_mask = 0x40;
+	bit_offset = 6;
+    }
+
+    other_decode_bitfield_value(bigbuf, oct, bit_mask, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  CLOCK_INCL: Clock information %sincluded",
+	bigbuf,
+	(oct & bit_mask) ? "" : "not ");
+
+    if (oct & bit_mask)
+    {
+	new_offset = offset;
+	temp_int = tvb_get_bits(tvb, &new_offset, &bit_offset, 18);
+
+	proto_tree_add_text(tree, tvb, offset, new_offset - offset,
+	    "CLOCK_BIAS: (%llu)",
+	    temp_int);
+
+	offset = new_offset;
+	temp_int = tvb_get_bits(tvb, &new_offset, &bit_offset, 16);
+
+	proto_tree_add_text(tree, tvb, offset, new_offset - offset,
+	    "CLOCK_DRIFT: (%llu)",
+	    temp_int);
+
+	offset = new_offset;
+	bit_mask = 0x80 >> (8 - bit_offset);
+	oct = tvb_get_guint8(tvb, offset);
+
+#ifdef MLUM
+	other_decode_bitfield_value(bigbuf, value, bit_mask, 16);
+	proto_tree_add_text(tree, tvb, offset, 2,
+	    "%s :  CLOCK_BIAS: (LSB)",
+	    bigbuf);
+
+	if (bit_offset - (18 - 16) > 0)
+	{
+	    bit_offset -= (18 - 16);
+	}
+	else
+	{
+	    bit_offset = 8 + (bit_offset - (18 - 16));
+	}
+
+	bit_mask = (0xff << (8 - bit_offset));
+	bit_mask >>= (8 - bit_offset);
+
+	temp_int = (value & (guint32) bit_mask) << (16 - bit_offset);
+
+	other_decode_bitfield_value(bigbuf, value, bit_mask, 8);
+
+	offset += 2;
+	value = tvb_get_ntohs(tvb, offset);
+
+	bit_mask = (0xffff << (16 - (18 - bit_offset)));
+	temp_int |= ((value & bit_mask) >> (16 - (18 - bit_offset)));
+
+	proto_tree_add_text(tree, tvb, offset-1, 1,
+	    "%s :  CLOCK_DRIFT: (MSB) (%llu)",
+	    bigbuf,
+	    temp_int);
+
+	other_decode_bitfield_value(bigbuf, value, bit_mask, 16);
+	proto_tree_add_text(tree, tvb, offset, 2,
+	    "%s :  CLOCK_DRIFT: (LSB)",
+	    bigbuf);
+
+	if (bit_offset - 2 > 0)
+	{
+	    bit_offset -= 2;
+	}
+	else
+	{
+	    bit_offset = 8 + (bit_offset - 2);
+	}
+
+	/* NOT FINISHED */
+#endif
+    }
+    else
+    {
+	/*
+	 * no code here just co-located comments for bit mask
+	 */
+	bit_mask >>= 1;
+	bit_offset--;
+    }
+
+    other_decode_bitfield_value(bigbuf, oct, bit_mask, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  HEIGHT_INCL: Height information %sincluded",
+	bigbuf,
+	(oct & bit_mask) ? "" : "not ");
+
+    if (oct & bit_mask)
+    {
+	new_offset = offset;
+	temp_int = tvb_get_bits(tvb, &new_offset, &bit_offset, 14);
+
+	proto_tree_add_text(tree, tvb, offset, new_offset - offset,
+	    "HEIGHT: (%llu)",
+	    temp_int);
+
+	offset = new_offset;
+	temp_int = tvb_get_bits(tvb, &new_offset, &bit_offset, 5);
+
+	proto_tree_add_text(tree, tvb, offset, new_offset - offset,
+	    "LOC_UNCRTNTY_V: (%llu)",
+	    temp_int);
+
+	offset = new_offset;
+	bit_mask = 0x80 >> (8 - bit_offset);
+	oct = tvb_get_guint8(tvb, offset);
+
+#ifdef MLUM
+	/* NOT FINISHED */
+#endif
+    }
+    else
+    {
+	/*
+	 * no code here just co-located comments for bit mask
+	 */
+	bit_mask >>= 1;
+	bit_offset--;
+    }
+
+    bit_mask = 0xff >> (8 - bit_offset);
+    other_decode_bitfield_value(bigbuf, oct, bit_mask, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+for_pr_loc_response(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    pr_loc_response(tvb, tree, len, offset);
+}
+
+static void
+for_pr_gps_sat_health(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint8	num_bad;
+    guint8	i;
+    guint8	bit_mask;
+    guint8	bit_offset;
+    guint32	new_offset;
+    guint32	saved_offset;
+    guint64	temp_int;
+
+    saved_offset = offset;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x80, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  BAD_SV_PRESENT: Bad GPS satellites present",
+	bigbuf);
+
+    if (oct & 0x80)
+    {
+	num_bad = (oct & 0x78) >> 3;
+
+	other_decode_bitfield_value(bigbuf, oct, 0x78, 8);
+	proto_tree_add_text(tree, tvb, offset, 1,
+	    "%s :  NUM_BAD_SV: The number of bad GPS satellites: (%u)",
+	    bigbuf,
+	    num_bad);
+
+	bit_offset = 3;
+	new_offset = offset;
+
+	for (i=0; i < num_bad; i++)
+	{
+	    temp_int = tvb_get_bits(tvb, &new_offset, &bit_offset, 5);
+
+	    proto_tree_add_text(tree, tvb, offset, 1,
+		"BAD_SV_PRN_NUM: (%llu)",
+		temp_int);
+
+	    offset = new_offset;
+	}
+
+	bit_mask = 0xff >> (8 - bit_offset);
+	oct = tvb_get_guint8(tvb, offset);
+    }
+    else
+    {
+	bit_mask = 0x7f;
+    }
+
+    if (bit_mask != 0x00)
+    {
+	other_decode_bitfield_value(bigbuf, oct, bit_mask, 8);
+	proto_tree_add_text(tree, tvb, offset, 1,
+	    "%s :  Reserved",
+	    bigbuf);
+
+	offset++;
+    }
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+rev_req_gps_acq_ass(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint32	saved_offset;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    saved_offset = offset;
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x80, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Doppler (0th order) term %srequested",
+	bigbuf,
+	(oct & 0x80) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, oct, 0x40, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Additional Doppler terms %srequested",
+	bigbuf,
+	(oct & 0x40) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, oct, 0x20, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Code phase parameters %srequested",
+	bigbuf,
+	(oct & 0x20) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, oct, 0x10, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Azimuth and elevation angle %srequested",
+	bigbuf,
+	(oct & 0x10) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, oct, 0x0f, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+rev_req_gps_loc_ass(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint32	saved_offset;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    saved_offset = offset;
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x80, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Coordinate type requested: %s coordinates",
+	bigbuf,
+	(oct & 0x80) ? "Sperical" : "Cartesian");
+
+    other_decode_bitfield_value(bigbuf, oct, 0x7f, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+rev_req_bs_alm(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint32	saved_offset;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    saved_offset = offset;
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x80, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Extended base station almanac %srequested",
+	bigbuf,
+	(oct & 0x80) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, oct, 0x7f, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+rev_req_gps_ephemeris(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint32	saved_offset;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    saved_offset = offset;
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x80, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Alpha and Beta parameters %srequested",
+	bigbuf,
+	(oct & 0x80) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, oct, 0x7f, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+rev_req_gps_nav_msg_bits(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint32	saved_offset;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    saved_offset = offset;
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x80, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Subframes 4 and 5 %srequested",
+	bigbuf,
+	(oct & 0x80) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, oct, 0x7f, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+rev_req_loc_response(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint32	saved_offset;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    saved_offset = offset;
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x80, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Height information %srequested",
+	bigbuf,
+	(oct & 0x80) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, oct, 0x40, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Clock correction for GPS time %srequested",
+	bigbuf,
+	(oct & 0x40) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, oct, 0x20, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Velocity information %srequested",
+	bigbuf,
+	(oct & 0x20) ? "" : "not ");
+
+    other_decode_bitfield_value(bigbuf, oct, 0x1f, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+rev_req_gps_alm_correction(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint32	saved_offset;
+
+    SHORT_DATA_CHECK(len, 2);
+
+    saved_offset = offset;
+
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"Time of almanac (in units of 4096 seconds)");
+
+    offset++;
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"GPS week number (8 least significant bits)");
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+rev_reject(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint32	saved_offset;
+    const gchar	*str = NULL;
+    gint	idx;
+
+    saved_offset = offset;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    str = match_strval_idx((oct & 0xf0) >> 4, for_req_type_strings, &idx);
+    if (str == NULL)
+    {
+	str = "Reserved";
+    }
+
+    other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reject request type: (%u) %s",
+	bigbuf,
+	(oct & 0xf0) >> 4,
+	str);
+
+    switch ((oct & 0x0e) >> 1)
+    {
+    case 0x00: str = "Capability not supported by the mobile station"; break;
+    case 0x01: str = "Capability normally supported by the mobile station but temporarily not available or not enabled"; break;
+    default: str = "Reserved"; break;
+    }
+
+    other_decode_bitfield_value(bigbuf, oct, 0x0e, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reject reason: %s",
+	bigbuf,
+	str);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x01, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+rev_pr_ms_information(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint32	value;
+    guint32	saved_offset;
+    const gchar	*str = NULL;
+
+    saved_offset = offset;
+
+    SHORT_DATA_CHECK(len, 5);
+
+    value = tvb_get_ntohs(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value, 0xfc00, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  MS_LS_REV",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x03c0, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  MS_MODE",
+	bigbuf);
+
+    switch (value & 0x003f)
+    {
+    case 0x00: str = "Full Chip Measurement Capability"; break;
+    case 0x01: str = "Half Chip Measurement Capability"; break;
+    case 0x02: str = "Quarter Chip Measurement Capability"; break;
+    case 0x03: str = "Eighth Chip Measurement Capability"; break;
+    case 0x04: str = "One Sixteenth Chip Measurement Capability"; break;
+    default: str = "Reserved"; break;
+    }
+
+    other_decode_bitfield_value(bigbuf, value, 0x003f, 16);
+    proto_tree_add_text(tree, tvb, offset, 2,
+	"%s :  PILOT_PH_CAP: (%u) %s",
+	bigbuf,
+	value & 0x3f,
+	str);
+
+    offset += 2;
+    value = tvb_get_ntoh24(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value, 0xf80000, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  GPS_ACQ_CAP:  Reserved",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x040000, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  GPS_ACQ_CAP:  GPS Autonomous Acquisition Capable",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x020000, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  GPS_ACQ_CAP:  GPS Almanac Correction",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x010000, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  GPS_ACQ_CAP:  GPS Navigation Message Bits",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x008000, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  GPS_ACQ_CAP:  GPS Ephemeris",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x004000, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  GPS_ACQ_CAP:  GPS Almanac",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x002000, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  GPS_ACQ_CAP:  GPS Sensitivity Assistance",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x001000, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  GPS_ACQ_CAP:  GPS Acquisition Assistance",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000800, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LOC_CALC_CAP:  Pre-programmed Location",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000700, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LOC_CALC_CAP:  Reserved",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000080, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LOC_CALC_CAP:  Hybrid GPS and AFLT Location Calculation Capable",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000040, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LOC_CALC_CAP:  Autonomous Location Calculation Capable",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000020, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LOC_CALC_CAP:  Location Calculation Capable using GPS Almanac Correction",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000010, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LOC_CALC_CAP:  Location Calculation Capable using GPS Ephemeris Assistance",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000008, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LOC_CALC_CAP:  Location Calculation Capable using GPS Almanac Assistance",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000004, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LOC_CALC_CAP:  Advanced Forward Link Trilateration (AFLT) Location Calculation Capable",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000002, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LOC_CALC_CAP:  Location Calculation Capable using Location Assistance - Cartesian",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000001, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  LOC_CALC_CAP:  Location Calculation Capable using Location Assistance - Spherical",
+	bigbuf);
+
+    offset += 3;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+rev_pr_loc_response(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    pr_loc_response(tvb, tree, len, offset);
+}
+
+static void
+rev_pr_time_off_meas(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint32	value;
+    guint32	saved_offset;
+
+    saved_offset = offset;
+
+    SHORT_DATA_CHECK(len, 6);
+
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"TIME_REF_MS:  The time of validity of the parameters reported in this response element.");
+
+    offset += 3;
+    value = tvb_get_ntoh24(tvb, offset);
+
+    other_decode_bitfield_value(bigbuf, value, 0xff8000, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  REF_PN: (%u)",
+	bigbuf,
+	(value & 0xff8000) >> 15);
+
+    other_decode_bitfield_value(bigbuf, value, 0x007ffe, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  MOB_SYS_T_OFFSET: (%u)",
+	bigbuf,
+	(value & 0x007ffe) >> 1);
+
+    other_decode_bitfield_value(bigbuf, value, 0x000001, 24);
+    proto_tree_add_text(tree, tvb, offset, 3,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset += 3;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
+static void
+rev_pr_can_ack(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset)
+{
+    guint8	oct;
+    guint32	saved_offset;
+    const gchar	*str = NULL;
+    gint	idx;
+
+    saved_offset = offset;
+
+    SHORT_DATA_CHECK(len, 1);
+
+    oct = tvb_get_guint8(tvb, offset);
+
+    str = match_strval_idx((oct & 0xf0) >> 4, for_req_type_strings, &idx);
+    if (str == NULL)
+    {
+	str = "Reserved";
+    }
+
+    other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Cancellation Type: (%u) %s",
+	bigbuf,
+	(oct & 0xf0) >> 4,
+	str);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x08, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  No outstanding request element",
+	bigbuf);
+
+    other_decode_bitfield_value(bigbuf, oct, 0x07, 8);
+    proto_tree_add_text(tree, tvb, offset, 1,
+	"%s :  Reserved",
+	bigbuf);
+
+    offset++;
+
+    EXTRANEOUS_DATA_CHECK(len, offset - saved_offset);
+}
+
 static void (*for_req_type_fcn[])(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset) = {
     NULL,	/* Reserved */
-    NULL,	/* Request MS Information */
-    NULL,	/* Request Autonomous Measurement Weighting Factors */
+    NULL, /* no data */	/* Request MS Information */
+    NULL, /* no data */	/* Request Autonomous Measurement Weighting Factors */
     for_req_pseudo_meas,	/* Request Pseudorange Measurement */
-    NULL,	/* Request Pilot Phase Measurement */
-    NULL,	/* Request Location Response */
-    NULL,	/* Request Time Offset Measurement */
-    NULL,	/* Request Cancellation */
+    for_req_pilot_ph_meas,	/* Request Pilot Phase Measurement */
+    for_req_loc_response,	/* Request Location Response */
+    for_req_time_off_meas,	/* Request Time Offset Measurement */
+    for_req_cancel,	/* Request Cancellation */
     NULL,	/* NONE */
 };
 
-static const value_string for_rsp_type_strings[] = {
-    { 0,	"Reject" },
-    { 2,	"Provide BS Capabilities" },
-    { 4,	"Provide GPS Acquisition Assistance" },
-    { 6,	"Provide GPS Location Assistance Spherical Coordinates" },
-    { 7,	"Provide GPS Location Assistance Cartesian Coordinates" },
-    { 5,	"Provide GPS Sensitivity Assistance" },
-    { 3,	"Provide Base Station Almanac" },
-    { 8,	"Provide GPS Almanac" },
-    { 9,	"Provide GPS Ephemeris" },
-    { 10,	"Provide GPS Navigation Message Bits" },
-    { 1,	"Provide Location Response" },
-    { 11,	"Provide GPS Almanac Correction" },
-    { 12,	"Provide GPS Satellite Health Information" },
-    { 0, NULL },
-};
-#define	NUM_FOR_RSP_TYPE (sizeof(for_rsp_type_strings)/sizeof(value_string))
-static gint ett_for_rsp_type[NUM_FOR_RSP_TYPE];
 static void (*for_rsp_type_fcn[])(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset) = {
-    NULL,	/* Reject */
-    NULL,	/* Provide BS Capabilities */
+    for_reject,	/* Reject */
+    for_pr_bs_cap,	/* Provide BS Capabilities */
     NULL,	/* Provide GPS Acquisition Assistance */
     NULL,	/* Provide GPS Location Assistance Spherical Coordinates */
     NULL,	/* Provide GPS Location Assistance Cartesian Coordinates */
-    NULL,	/* Provide GPS Sensitivity Assistance */
+    for_pr_gps_sense_ass,	/* Provide GPS Sensitivity Assistance */
     NULL,	/* Provide Base Station Almanac */
-    NULL,	/* Provide GPS Almanac */
+    for_pr_gps_almanac,	/* Provide GPS Almanac */
     NULL,	/* Provide GPS Ephemeris */
-    NULL,	/* Provide GPS Navigation Message Bits */
-    NULL,	/* Provide Location Response */
+    for_pr_gps_nav_msg_bits,	/* Provide GPS Navigation Message Bits */
+    for_pr_loc_response,	/* Provide Location Response */
     NULL,	/* Provide GPS Almanac Correction */
-    NULL,	/* Provide GPS Satellite Health Information */
+    for_pr_gps_sat_health,	/* Provide GPS Satellite Health Information */
     NULL,	/* NONE */
 };
 
-static const value_string rev_req_type_strings[] = {
-    { 0,	"Reserved" },
-    { 2,	"Request BS Capabilities" },
-    { 4,	"Request GPS Acquisition Assistance" },
-    { 6,	"Request GPS Location Assistance" },
-    { 7,	"Reserved" },
-    { 5,	"Request GPS Sensitivity Assistance" },
-    { 3,	"Request Base Station Almanac" },
-    { 8,	"Request GPS Almanac" },
-    { 9,	"Request GPS Ephemeris" },
-    { 10,	"Request GPS Navigation Message Bits" },
-    { 1,	"Request Location Response" },
-    { 11,	"Request GPS Almanac Correction" },
-    { 12,	"Request GPS Satellite Health Information" },
-    { 0, NULL },
-};
-#define	NUM_REV_REQ_TYPE (sizeof(rev_req_type_strings)/sizeof(value_string))
-static gint ett_rev_req_type[NUM_REV_REQ_TYPE];
 static void (*rev_req_type_fcn[])(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset) = {
     NULL,	/* Reserved */
-    NULL,	/* Request BS Capabilities */
-    NULL,	/* Request GPS Acquisition Assistance */
-    NULL,	/* Request GPS Location Assistance */
+    NULL, /* no data */	/* Request BS Capabilities */
+    rev_req_gps_acq_ass,	/* Request GPS Acquisition Assistance */
+    rev_req_gps_loc_ass,	/* Request GPS Location Assistance */
     NULL,	/* Reserved */
-    NULL,	/* Request GPS Sensitivity Assistance */
-    NULL,	/* Request Base Station Almanac */
-    NULL,	/* Request GPS Almanac */
-    NULL,	/* Request GPS Ephemeris */
-    NULL,	/* Request GPS Navigation Message Bits */
-    NULL,	/* Request Location Response */
-    NULL,	/* Request GPS Almanac Correction */
-    NULL,	/* Request GPS Satellite Health Information */
+    NULL, /* no data */	/* Request GPS Sensitivity Assistance */
+    rev_req_bs_alm,	/* Request Base Station Almanac */
+    NULL, /* no data */	/* Request GPS Almanac */
+    rev_req_gps_ephemeris,	/* Request GPS Ephemeris */
+    rev_req_gps_nav_msg_bits,	/* Request GPS Navigation Message Bits */
+    rev_req_loc_response,	/* Request Location Response */
+    rev_req_gps_alm_correction,	/* Request GPS Almanac Correction */
+    NULL, /* no data */	/* Request GPS Satellite Health Information */
     NULL,	/* NONE */
 };
 
-static const value_string rev_rsp_type_strings[] = {
-    { 0,	"Reject" },
-    { 2,	"Provide MS Information" },
-    { 3,	"Provide Autonomous Measurement Weighting Factors" },
-    { 4,	"Provide Pseudorange Measurement" },
-    { 5,	"Provide Pilot Phase Measurement" },
-    { 1,	"Provide Location Response" },
-    { 6,	"Provide Time Offset Measurement" },
-    { 7,	"Provide Cancellation Acknowledgement" },
-    { 0, NULL },
-};
-#define	NUM_REV_RSP_TYPE (sizeof(rev_rsp_type_strings)/sizeof(value_string))
-static gint ett_rev_rsp_type[NUM_REV_RSP_TYPE];
 static void (*rev_rsp_type_fcn[])(tvbuff_t *tvb, proto_tree *tree, guint len, guint32 offset) = {
-    NULL,	/* Reject */
-    NULL,	/* Provide MS Information */
+    rev_reject,	/* Reject */
+    rev_pr_ms_information,	/* Provide MS Information */
     NULL,	/* Provide Autonomous Measurement Weighting Factors */
     NULL,	/* Provide Pseudorange Measurement */
     NULL,	/* Provide Pilot Phase Measurement */
-    NULL,	/* Provide Location Response */
-    NULL,	/* Provide Time Offset Measurement */
-    NULL,	/* Provide Cancellation Acknowledgement */
+    rev_pr_loc_response,	/* Provide Location Response */
+    rev_pr_time_off_meas,	/* Provide Time Offset Measurement */
+    rev_pr_can_ack,	/* Provide Cancellation Acknowledgement */
     NULL,	/* NONE */
 };
 
 static void
-for_request(tvbuff_t *tvb, proto_tree *tree, guint32 *offset_p)
+for_request(tvbuff_t *tvb, proto_tree *tree, guint32 *offset_p, guint8 pd_msg_type)
 {
     guint32	offset;
     guint8	oct;
@@ -295,27 +1823,38 @@ for_request(tvbuff_t *tvb, proto_tree *tree, guint32 *offset_p)
     offset = *offset_p;
     oct = tvb_get_guint8(tvb, offset);
 
-    other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
-    proto_tree_add_text(tree, tvb, offset, 1,
-	"%s :  Reserved",
-	bigbuf);
+    if (pd_msg_type == 0x00)
+    {
+	other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
+	proto_tree_add_text(tree, tvb, offset, 1,
+	    "%s :  Reserved",
+	    bigbuf);
 
-    str = match_strval_idx(oct & 0x0f, for_req_type_strings, &idx);
+	str = match_strval_idx(oct & 0x0f, for_req_type_strings, &idx);
+	if (str == NULL)
+	{
+	    return;
+	}
 
-    if (str == NULL)
+	other_decode_bitfield_value(bigbuf, oct, 0x0f, 8);
+	item =
+	    proto_tree_add_uint_format(tree, hf_ansi_801_for_req_type, tvb, offset,
+		1, oct & 0x0f,
+		"%s :  Request Type, %s (%u)",
+		bigbuf,
+		str,
+		oct & 0x0f);
+    }
+    else
     {
+	/* TBD */
+	/*
+	 * It is unclear from TIA-801-A how this was meant to be decoded.
+	 * Are the elements supposed to be byte aligned?
+	 */
 	return;
     }
 
-    other_decode_bitfield_value(bigbuf, oct, 0x0f, 8);
-    item =
-	proto_tree_add_uint_format(tree, hf_ansi_801_for_req_type, tvb, offset,
-	    1, oct & 0x0f,
-	    "%s :  Request Type, %s (%u)",
-	    bigbuf,
-	    str,
-	    oct & 0x0f);
-
     subtree = proto_item_add_subtree(item, ett_for_req_type[idx]);
 
     offset++;
@@ -327,14 +1866,17 @@ for_request(tvbuff_t *tvb, proto_tree *tree, guint32 *offset_p)
 
     offset++;
 
-    if (for_req_type_fcn[idx] != NULL)
-    {
-	(*for_req_type_fcn[idx])(tvb, subtree, oct, offset);
-    }
-    else
+    if (oct > 0)
     {
-	proto_tree_add_text(subtree, tvb, offset, oct,
-	    "Data");
+	if (for_req_type_fcn[idx] != NULL)
+	{
+	    (*for_req_type_fcn[idx])(tvb, subtree, oct, offset);
+	}
+	else
+	{
+	    proto_tree_add_text(subtree, tvb, offset, oct,
+		"Data");
+	}
     }
 
     *offset_p = offset + oct;
@@ -404,7 +1946,7 @@ for_response(tvbuff_t *tvb, proto_tree *tree, guint32 *offset_p)
 }
 
 static void
-rev_request(tvbuff_t *tvb, proto_tree *tree, guint32 *offset_p)
+rev_request(tvbuff_t *tvb, proto_tree *tree, guint32 *offset_p, guint8 pd_msg_type)
 {
     guint32	offset;
     guint8	oct;
@@ -416,27 +1958,38 @@ rev_request(tvbuff_t *tvb, proto_tree *tree, guint32 *offset_p)
     offset = *offset_p;
     oct = tvb_get_guint8(tvb, offset);
 
-    other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
-    proto_tree_add_text(tree, tvb, offset, 1,
-	"%s :  Reserved",
-	bigbuf);
+    if (pd_msg_type == 0x00)
+    {
+	other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
+	proto_tree_add_text(tree, tvb, offset, 1,
+	    "%s :  Reserved",
+	    bigbuf);
 
-    str = match_strval_idx(oct & 0x0f, rev_req_type_strings, &idx);
+	str = match_strval_idx(oct & 0x0f, rev_req_type_strings, &idx);
+	if (str == NULL)
+	{
+	    return;
+	}
 
-    if (str == NULL)
+	other_decode_bitfield_value(bigbuf, oct, 0x0f, 8);
+	item =
+	    proto_tree_add_uint_format(tree, hf_ansi_801_rev_req_type, tvb, offset,
+		1, oct & 0x0f,
+		"%s :  Request Type, %s (%u)",
+		bigbuf,
+		str,
+		oct & 0x0f);
+    }
+    else
     {
+	/* TBD */
+	/*
+	 * It is unclear from TIA-801-A how this was meant to be decoded.
+	 * Are the elements supposed to be byte aligned?
+	 */
 	return;
     }
 
-    other_decode_bitfield_value(bigbuf, oct, 0x0f, 8);
-    item =
-	proto_tree_add_uint_format(tree, hf_ansi_801_rev_req_type, tvb, offset,
-	    1, oct & 0x0f,
-	    "%s :  Request Type, %s (%u)",
-	    bigbuf,
-	    str,
-	    oct & 0x0f);
-
     subtree = proto_item_add_subtree(item, ett_rev_req_type[idx]);
 
     offset++;
@@ -527,8 +2080,9 @@ rev_response(tvbuff_t *tvb, proto_tree *tree, guint32 *offset_p)
 static void
 dissect_ansi_801_for_message(tvbuff_t *tvb, proto_tree *tree)
 {
+    guint32	value;
     guint32	offset;
-    guint8	oct, num_req, num_rsp;
+    guint8	oct, num_req, num_rsp, pd_msg_type;
     guint	rem_len;
     const gchar	*str = NULL;
 
@@ -562,13 +2116,15 @@ dissect_ansi_801_for_message(tvbuff_t *tvb, proto_tree *tree)
 
     offset++;
     oct = tvb_get_guint8(tvb, offset);
+    pd_msg_type = oct;
 
-    switch (oct)
+    switch (pd_msg_type)
     {
     case 0x00: str = "Position Determination Data Message"; break;
+    case 0x01: str = "Position Determination Data Message"; break;
     case 0xff: str = "Reserved"; break;
     default:
-	if (oct < 0xc0)
+	if (pd_msg_type < 0xc0)
 	{
 	    str = "Reserved for future standardization";
 	}
@@ -581,16 +2137,70 @@ dissect_ansi_801_for_message(tvbuff_t *tvb, proto_tree *tree)
 	break;
     }
 
-    other_decode_bitfield_value(bigbuf, oct, 0xff, 8);
+    other_decode_bitfield_value(bigbuf, pd_msg_type, 0xff, 8);
     proto_tree_add_text(tree, tvb, offset, 1,
 	"%s :  PD Message Type, %s (%u)",
 	bigbuf,
 	str,
-	oct);
+	pd_msg_type);
 
     offset++;
 
-    if (oct == 0x00)
+    if ((pd_msg_type != 0x00) &&
+	(pd_msg_type != 0x01))
+    {
+	proto_tree_add_text(tree, tvb, offset, -1,
+	    "Reserved/Proprietary/Future Data");
+	return;
+    }
+
+    if (pd_msg_type == 0x01)
+    {
+	value = tvb_get_ntohs(tvb, offset);
+
+	other_decode_bitfield_value(bigbuf, value, 0xffc0, 16);
+	proto_tree_add_text(tree, tvb, offset, 2,
+	    "%s :  PD Message Length, (%u)",
+	    bigbuf,
+	    (value & 0xffc0) >> 6);
+
+	switch ((value & 0x0030) >> 4)
+	{
+	case 0x00: str = "No Regulatory service"; break;
+	case 0x01: str = "Emergency service"; break;
+	default: str = "Reserved"; break;
+	}
+
+	other_decode_bitfield_value(bigbuf, value, 0x0030, 16);
+	proto_tree_add_text(tree, tvb, offset, 2,
+	    "%s :  Regulatory Services Indicator, (%u)",
+	    bigbuf,
+	    str,
+	    (value & 0x0030) >> 4);
+
+	num_req = value & 0x000f;
+
+	other_decode_bitfield_value(bigbuf, value, 0x000f, 16);
+	proto_tree_add_text(tree, tvb, offset, 2,
+	    "%s :  Number Requests (%u)",
+	    bigbuf,
+	    num_req);
+
+	offset += 2;
+
+	oct = tvb_get_guint8(tvb, offset);
+
+	num_rsp = oct & 0xf0;
+
+	other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
+	proto_tree_add_text(tree, tvb, offset, 1,
+	    "%s :  Number Responses (%u)",
+	    bigbuf,
+	    num_rsp);
+
+	offset++;
+    }
+    else
     {
 	oct = tvb_get_guint8(tvb, offset);
 
@@ -608,60 +2218,56 @@ dissect_ansi_801_for_message(tvbuff_t *tvb, proto_tree *tree)
 	    "%s :  Number Responses (%u)",
 	    bigbuf,
 	    num_rsp);
+    }
 
-	offset++;
-	rem_len = tvb_length_remaining(tvb, offset);
-
-	while ((num_req > 0) &&
-	    (rem_len >= 2))
-	{
-	    for_request(tvb, tree, &offset);
+    offset++;
+    rem_len = tvb_length_remaining(tvb, offset);
 
-	    rem_len = tvb_length_remaining(tvb, offset);
-	    num_req--;
-	}
+    while ((num_req > 0) &&
+	(rem_len >= 2))
+    {
+	for_request(tvb, tree, &offset, pd_msg_type);
 
-	if (num_req != 0)
-	{
-	    proto_tree_add_text(tree, tvb,
-		offset, -1, "Short Data (?)");
-	    return;
-	}
+	rem_len = tvb_length_remaining(tvb, offset);
+	num_req--;
+    }
 
-	while ((num_rsp > 0) &&
-	    (rem_len >= 2))
-	{
-	    for_response(tvb, tree, &offset);
+    if (num_req != 0)
+    {
+	proto_tree_add_text(tree, tvb,
+	    offset, -1, "Short Data (?)");
+	return;
+    }
 
-	    rem_len = tvb_length_remaining(tvb, offset);
-	    num_rsp--;
-	}
+    while ((num_rsp > 0) &&
+	(rem_len >= 2))
+    {
+	for_response(tvb, tree, &offset);
 
-	if (num_rsp != 0)
-	{
-	    proto_tree_add_text(tree, tvb,
-		offset, -1, "Short Data (?)");
-	    return;
-	}
+	rem_len = tvb_length_remaining(tvb, offset);
+	num_rsp--;
+    }
 
-	if (rem_len > 0)
-	{
-	    proto_tree_add_text(tree, tvb, offset, rem_len,
-		"Extraneous Data");
-	}
+    if (num_rsp != 0)
+    {
+	proto_tree_add_text(tree, tvb,
+	    offset, -1, "Short Data (?)");
+	return;
     }
-    else
+
+    if (rem_len > 0)
     {
-	proto_tree_add_text(tree, tvb, offset, -1,
-	    "Reserved/Proprietary/Future Data");
+	proto_tree_add_text(tree, tvb, offset, rem_len,
+	    "Extraneous Data");
     }
 }
 
 static void
 dissect_ansi_801_rev_message(tvbuff_t *tvb, proto_tree *tree)
 {
+    guint32	value;
     guint32	offset;
-    guint8	oct, num_req, num_rsp;
+    guint8	oct, num_req, num_rsp, pd_msg_type;
     guint	rem_len;
     const gchar	*str = NULL;
 
@@ -695,13 +2301,15 @@ dissect_ansi_801_rev_message(tvbuff_t *tvb, proto_tree *tree)
 
     offset++;
     oct = tvb_get_guint8(tvb, offset);
+    pd_msg_type = oct;
 
-    switch (oct)
+    switch (pd_msg_type)
     {
     case 0x00: str = "Position Determination Data Message"; break;
+    case 0x01: str = "Position Determination Data Message"; break;
     case 0xff: str = "Reserved"; break;
     default:
-	if (oct < 0xc0)
+	if (pd_msg_type < 0xc0)
 	{
 	    str = "Reserved for future standardization";
 	}
@@ -714,16 +2322,70 @@ dissect_ansi_801_rev_message(tvbuff_t *tvb, proto_tree *tree)
 	break;
     }
 
-    other_decode_bitfield_value(bigbuf, oct, 0xff, 8);
+    other_decode_bitfield_value(bigbuf, pd_msg_type, 0xff, 8);
     proto_tree_add_text(tree, tvb, offset, 1,
 	"%s :  PD Message Type, %s (%u)",
 	bigbuf,
 	str,
-	oct);
+	pd_msg_type);
 
     offset++;
 
-    if (oct == 0x00)
+    if ((pd_msg_type != 0x00) &&
+	(pd_msg_type != 0x01))
+    {
+	proto_tree_add_text(tree, tvb, offset, -1,
+	    "Reserved/Proprietary/Future Data");
+	return;
+    }
+
+    if (pd_msg_type == 0x01)
+    {
+	value = tvb_get_ntohs(tvb, offset);
+
+	other_decode_bitfield_value(bigbuf, value, 0xffc0, 16);
+	proto_tree_add_text(tree, tvb, offset, 2,
+	    "%s :  PD Message Length, (%u)",
+	    bigbuf,
+	    (value & 0xffc0) >> 6);
+
+	switch ((value & 0x0030) >> 4)
+	{
+	case 0x00: str = "No Regulatory service"; break;
+	case 0x01: str = "Emergency service"; break;
+	default: str = "Reserved"; break;
+	}
+
+	other_decode_bitfield_value(bigbuf, value, 0x0030, 16);
+	proto_tree_add_text(tree, tvb, offset, 2,
+	    "%s :  Regulatory Services Indicator, (%u)",
+	    bigbuf,
+	    str,
+	    (value & 0x0030) >> 4);
+
+	num_req = value & 0x000f;
+
+	other_decode_bitfield_value(bigbuf, value, 0x000f, 16);
+	proto_tree_add_text(tree, tvb, offset, 2,
+	    "%s :  Number Requests (%u)",
+	    bigbuf,
+	    num_req);
+
+	offset += 2;
+
+	oct = tvb_get_guint8(tvb, offset);
+
+	num_rsp = oct & 0xf0;
+
+	other_decode_bitfield_value(bigbuf, oct, 0xf0, 8);
+	proto_tree_add_text(tree, tvb, offset, 1,
+	    "%s :  Number Responses (%u)",
+	    bigbuf,
+	    num_rsp);
+
+	offset++;
+    }
+    else
     {
 	oct = tvb_get_guint8(tvb, offset);
 
@@ -743,50 +2405,46 @@ dissect_ansi_801_rev_message(tvbuff_t *tvb, proto_tree *tree)
 	    num_rsp);
 
 	offset++;
-	rem_len = tvb_length_remaining(tvb, offset);
+    }
 
-	while ((num_req > 0) &&
-	    (rem_len >= 2))
-	{
-	    rev_request(tvb, tree, &offset);
+    rem_len = tvb_length_remaining(tvb, offset);
 
-	    rem_len = tvb_length_remaining(tvb, offset);
-	    num_req--;
-	}
+    while ((num_req > 0) &&
+	(rem_len >= 2))
+    {
+	rev_request(tvb, tree, &offset, pd_msg_type);
 
-	if (num_req != 0)
-	{
-	    proto_tree_add_text(tree, tvb,
-		offset, -1, "Short Data (?)");
-	    return;
-	}
+	rem_len = tvb_length_remaining(tvb, offset);
+	num_req--;
+    }
 
-	while ((num_rsp > 0) &&
-	    (rem_len >= 2))
-	{
-	    rev_response(tvb, tree, &offset);
+    if (num_req != 0)
+    {
+	proto_tree_add_text(tree, tvb,
+	    offset, -1, "Short Data (?)");
+	return;
+    }
 
-	    rem_len = tvb_length_remaining(tvb, offset);
-	    num_rsp--;
-	}
+    while ((num_rsp > 0) &&
+	(rem_len >= 2))
+    {
+	rev_response(tvb, tree, &offset);
 
-	if (num_rsp != 0)
-	{
-	    proto_tree_add_text(tree, tvb,
-		offset, -1, "Short Data (?)");
-	    return;
-	}
+	rem_len = tvb_length_remaining(tvb, offset);
+	num_rsp--;
+    }
 
-	if (rem_len > 0)
-	{
-	    proto_tree_add_text(tree, tvb, offset, rem_len,
-		"Extraneous Data");
-	}
+    if (num_rsp != 0)
+    {
+	proto_tree_add_text(tree, tvb,
+	    offset, -1, "Short Data (?)");
+	return;
     }
-    else
+
+    if (rem_len > 0)
     {
-	proto_tree_add_text(tree, tvb, offset, -1,
-	    "Reserved/Proprietary/Future Data");
+	proto_tree_add_text(tree, tvb, offset, rem_len,
+	    "Extraneous Data");
     }
 }