Infinite HDL synthesis - vhdl

Question

Whenver I try to synthesize my code, it is caught in an infinite loop i.e it is stuck at HDL SYNTHESIS. I have not used any loops. But problem persists.
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library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use IEEE.NUMERIC_STD.ALL;
entity mat is
port(
start,clck,start4,add4,check4,delete3,start3,add3,final3,load,load3,load4,search3:in std_logic;
data1,data2,newitem:in std_logic_vector(0 to 8);
completeload4tocontroller,completeadd3,search3cmplt,completeload3tocontroller,
completeloadtocontroller,discerncomplete,complete4add,completedel3,step4comptocntrl:out bit;
data4,data6:out std_logic_vector(0 to 15));
end mat;
architecture Behavioral of mat is
type positiveelem is array (0 to 255) of std_logic_vector(0 to 18);
type negativeelem is array (0 to 255) of std_logic_vector(0 to 18);
signal poselem:positiveelem ;
signal negelem:negativeelem ;
signal pospointer:integer range 0 to 255:=0;
signal negpointer:integer range 0 to 255:=0;
signal jpst:integer range 0 to 255 := 0;
signal jnst:integer range 0 to 255 := 0;
signal jp1st:integer range 0 to 255 := 0;
signal jp2st:integer range 0 to 255 := 0;
signal jn4st:integer range 0 to 255 := 0;
signal jp4st:integer range 0 to 255 := 0;
signal j3pntr:integer range 0 to 255 := 0;
signal j3npntr:integer range 0 to 255 := 0;
signal j3ptr:integer range 0 to 255 := 0;
type list12 is array(0 to 65535) of integer range 0 to 31;
signal clist:list12;
signal limitcount:integer range 0 to 255 :=0;
signal flag1:std_logic :='0';
signal position:integer range 0 to 255;
begin
P1:process(load,load4,clck,load3,check4,start,add4,start4,start3,delete3,add3)
variable temp4:std_logic_vector(0 to 15);
variable temp5:std_logic_vector(0 to 15);
variable temp1:std_logic_vector(0 to 15);
variable tempp3:std_logic_vector(0 to 15);
begin
if(rising_edge(clck))then
if(load='1')then
poselem(pospointer) <= data1;
negelem(negpointer) <= data2;
pospointer <= pospointer + 1;
negpointer <= negpointer + 1;
limitcount <= limitcount + 1;
if(limitcount = 10)then
completeloadtocontroller <= '1';
end if;
elsif((load4 = '1') and (load ='0'))then
poselem(pospointer) <= newitem;
pospointer <= pospointer + 1;
completeload4tocontroller <= '1';
elsif((load3 = '1') and (load = '0'))then
negelem(negpointer) <= newitem;
negpointer <= negpointer + 1;
completeload3tocontroller <= '1';
elsif(start = '1')then
if((jpst <= pospointer) and (jnst <= negpointer))then
temp4 := poselem(jpst)(0 to 15) xor negelem(jnst)(0 to 15);
clist(conv_integer(temp4)) <= clist(conv_integer(temp4)) + 1;
if((jnst = (negpointer - 1)) and (jpst < (pospointer - 1)))then
jnst <= 0;
jpst <= jpst + 1;
elsif(jnst < (negpointer - 1) and (jpst < (pospointer - 1)))then
jnst <= jnst + 1;
elsif(jpst = (pospointer - 1) and (jnst < (negpointer - 1)))then
jnst <= jnst + 1;
elsif((jp1st = pospointer) and (jp2st = pospointer) and
(jpst = pospointer) and (jnst = negpointer))then
discerncomplete <= '1';
end if;
end if;
elsif(start4 = '1')then
if(add4 = '1')then
temp1 := newitem(0 to 15) xor negelem(jn4st)(0 to 15);
if(clist(conv_integer(temp1)) = 0)then
data4 <= temp1;
end if;
clist(conv_integer(temp1)) <= clist(conv_integer(temp1)) + 1;
if(jn4st < (negpointer - 1))then
jn4st <= jn4st + 1;
elsif((jp4st = pospointer - 1) and (jn4st = negpointer - 1))then
complete4add <= '1';
end if;
end if;
elsif(start3 = '1')then
if(delete3 = '1')then
if((poselem(position)(0 to 15) /= poselem(j3pntr))
and (poselem(position)(16 to 18) /= poselem(j3pntr)(16 to 18)))then
tempp3 := poselem(position)(0 to 15) xor poselem(j3pntr)(0 to 15);
if(clist(conv_integer(tempp3)) = 1)then
data6 <= tempp3;
end if;
if(clist(conv_integer(tempp3)) /= 0)then
clist(conv_integer(tempp3)) <= clist(conv_integer(tempp3)) - 1;
end if;
if(j3pntr < (pospointer - 1))then
j3pntr <= j3pntr + 1;
elsif((j3pntr = pospointer - 1) and (j3npntr = negpointer - 1))then
completedel3 <= '1';
poselem(position) <= "0000000000000000000";
end if;
end if;
elsif(search3 = '1')then
if((poselem(position)(16 to 18) /= newitem(16 to 18))
and (poselem(position)(0 to 15) = newitem(0 to 15)))then
flag1 <= '1';
end if;
if((position < pospointer) and (flag1 = '0'))then
position <= position + 1;
elsif(flag1 = '1')then
search3cmplt <= '1';
end if;
elsif(add3 = '1')then
tempp3 := newitem(0 to 15) xor poselem(j3ptr)(0 to 15);
if(clist(conv_integer(tempp3)) = 0)then
data4 <= tempp3;
end if;
clist(conv_integer(tempp3)) <= clist(conv_integer(tempp3)) + 1;
if(j3ptr < pospointer - 1 and (j3ptr = (position - 1)))then
j3ptr <= j3ptr + 2;
elsif(j3ptr = (pospointer - 1))then
completeadd3 <= '1';
else
j3ptr <= j3ptr + 1;
end if;
end if;
end if;
end if;
if(falling_edge(clck))then
if(start = '1')then
if((jp1st /= pospointer) and (jp2st /= pospointer) and (poselem(jp1st)(16 to 18) /= poselem(jp2st)(16 to 18))
and (poselem(jp1st)(0 to 15) /= poselem(jp2st)(0 to 15))) then
temp5 := poselem(jp1st)(0 to 15) xor poselem(jp2st)(0 to 15);
clist(conv_integer(temp5)) <= clist(conv_integer(temp5)) + 1;
end if;
if(jp1st < (pospointer - 1) and jp2st = (pospointer-1))then
jp1st <= jp1st + 1;
jp2st <= 0;
elsif(jp1st = (pospointer - 1) and jp2st < (pospointer-1))then
jp2st <= jp2st + 1;
elsif(jp1st < (pospointer - 1) and jp2st < (pospointer-1))then
jp2st <= jp2st + 1;
elsif((jp1st = pospointer) and (jp2st = pospointer) and (jpst = pospointer) and (jnst = negpointer))then
discerncomplete <= '1';
end if;
elsif(start4 = '1')then
if(add4 = '1')then
if((poselem(jp4st)(0 to 15) /= "0000000000000000"))then
if(poselem(jp4st)(0 to 15) /= newitem(0 to 15))
and (poselem(jp4st)(16 to 18) /= newitem(16 to 18)))then
temp1 := newitem(0 to 15) xor poselem(jp4st)(0 to 15);
if(clist(conv_integer(temp1)) = 0)then
data4 <= temp1;
end if;
clist(conv_integer(temp1)) <= clist(conv_integer(temp1)) + 1;
end if;
if(jp4st < (pospointer - 1))then
jp4st <= jp4st + 1;
elsif((jp4st = pospointer - 1) and (jn4st = negpointer - 1))then
complete4add <= '1';
end if;
end if;
elsif(start3 = '1')then
if(delete3 = '1')then
tempp3 := newitem(0 to 15) xor negelem(j3npntr)(0 to 15);
if(clist(conv_integer(tempp3)) = 1)then
data6 <= tempp3;
end if;
if(clist(conv_integer(tempp3)) = 0)then
clist(conv_integer(tempp3)) <= clist(conv_integer(tempp3)) - 1;
end if;
if(j3npntr < negpointer - 1 )then
j3npntr <= j3npntr + 1;
elsif((j3pntr = pospointer - 1) and (j3npntr = negpointer - 1))then
completedel3 <= '1';
poselem(position) <= "0000000000000000000";
end if;
end if;
end if;
end if;
end process P1;
end Behavioral;

Answer 1

My comments address some of these issues, but I thought I'd type them up as an answer to add a little more detail and clarification.
Synthesis software getting stuck at a certain step and locking up has little to nothing to do with any particular language structure you're using, and probably means the software is having trouble parsing your code. While I would call this a bug in the software, you can probably get around it by looking for syntax errors (using another compiler, like ModelSim or something, might also help, if you have access). For instance, you appear to have an if-loop you're not closing somewhere under if falling_edge(clck). You also have a missing ( on the lines:
if(poselem(jp4st)(0 to 15) /= newitem(0 to 15))
and (poselem(jp4st)(16 to 18) /= newitem(16 to 18)))then
And you're assigning data1, a 9-bit vector, to poselem(pospointer), a 19-bit vector (and other similar assignments). Check your port and signal definitions.