-- (c) William Welch 2005
--
-- This software is provided 'as-is', without any express or implied 
-- warranty. In no event will the authors be held liable for any damages 
-- arising from the use of this software.
--
-- Permission is granted to anyone to use this software for any purpose, 
-- including commercial applications, and to alter it and redistribute it 
-- freely, subject to the following restrictions:
--
-- 1. The origin of this software must not be misrepresented; 
--    you must not claim that you wrote the original software. 
--    If you use this software in a product, an acknowledgment in 
--    the product documentation would be appreciated but is not required.
--
-- 2. Altered source versions must be plainly marked as such, and must 
--    not be misrepresented as being the original software.
--
-- 3. This notice may not be removed or altered from any source distribution.
--
-- This license is commonly known as the zlib/libpng License.
--
-- william welch 5 march 2005. ram data structures and support routines
-- revised 18 march 2005, use Javi's "pointer" approach and routines.

-- storage for the pointers themselves
const PKT = Pointers_Seed
CONST UDP_PSEUDO = PKT + 2
CONST TCP_PSEUDO = UDP_PSEUDO + 2
const IP_OFF = TCP_PSEUDO + 2
const UDP_OFF = IP_OFF + 2
const UDP_APP_OFF = UDP_OFF + 2
const TCP_OFF = UDP_APP_OFF + 2
const ICMP_OFF = TCP_OFF + 2
CONST MYMAC = ICMP_OFF + 2
const TBUF = MYMAC + 2
const MYSSID = TBUF + 2
const MYIP = MYSSID + 2
const TELNET_CONN = MYIP + 2
const HTTP_CONN = TELNET_CONN + 2
const SUM32 = HTTP_CONN + 2
const CHKTMP = SUM32 + 2
const SEG_SEQ = CHKTMP + 2
CONST SEG_ACK = SEG_SEQ + 2
CONST TCP_CLK = SEG_ACK + 2
CONST RCV_NXT = TCP_CLK + 2
CONST SND_NXT = RCV_NXT + 2
CONST P_K16 = SND_NXT + 2
CONST P_N16 = P_K16 + 2
CONST ZERO16 = P_N16 + 2
CONST L16 = ZERO16 + 2
CONST IP_LEN = L16 + 2
CONST UDP_LEN = IP_LEN + 2
CONST TCP_APP_OFF = UDP_LEN + 2
CONST FILE_CONN = TCP_APP_OFF + 2
CONST NE2K_CLK = FILE_CONN + 2

const RAM_GPR = 0x01
const RBASE = 0x100
const TBUFSZ = 50
const TCP_CONN_SZ = 36
const FILE_CONN_SZ = 2

const byte udp_hdrsize = 8
const byte ip_hdrsize = 20 

SetPointer ( MYMAC , RBASE >> 8 , RBASE & 0xff )
SetPointerRel ( TBUF , MYMAC , 6 )
SetPointerRel ( MYSSID , TBUF , TBUFSZ )
SetPointerRel ( MYIP , MYSSID , 32 )
SetPointerRel ( TELNET_CONN , MYIP , 4 )
SetPointerRel ( HTTP_CONN , TELNET_CONN , TCP_CONN_SZ )
SetPointerRel ( FILE_CONN , HTTP_CONN , TCP_CONN_SZ )     
SetPointerRel ( SUM32 , FILE_CONN , FILE_CONN_SZ )
SetPointerRel ( UDP_PSEUDO , SUM32 , 4 )
-- note: tcp_pseudo shares the same space with udp_pseudo
SetPointerRel ( TCP_PSEUDO , UDP_PSEUDO , 0 )
SetPointerRel ( CHKTMP , TCP_PSEUDO , 12 )
SetPointerRel ( TCP_CLK , CHKTMP , 4 )
SetPointerRel ( P_K16, TCP_CLK , 4 )
SetPointerRel ( P_N16, P_K16 , 2 )
SetPointerRel ( ZERO16, P_N16 , 2 )
SetPointerRel ( L16, ZERO16, 2 )
SetPointerRel ( NE2K_CLK, L16 , 2 )

-- It is recommended that PKT be the last item defined. 
-- So it can grow towards the top/end of RAM.
SetPointerRel ( PKT, NE2K_CLK , 2 )

-- these pointers are pointing to areas within the packet.
SetPointerRel ( IP_OFF , PKT , 14 )
SetPointerRel ( IP_LEN, IP_OFF , 2 )
SetPointerRel ( TCP_OFF, IP_OFF , ip_hdrsize )
SetPointerRel ( ICMP_OFF, IP_OFF , ip_hdrsize )
SetPointerRel ( UDP_OFF, IP_OFF , ip_hdrsize )
SetPointerRel ( UDP_LEN, UDP_OFF , 4 )
SetPointerRel ( UDP_APP_OFF, UDP_OFF , udp_hdrsize )
SetPointerRel ( SEG_SEQ, TCP_OFF , 4 )
SetPointerRel ( SEG_ACK, TCP_OFF , 8 )

I16_LDL ( ZERO16 , 0 , 0 )