HELP: C/C++ equivalent of dos,crt Pascal units

I am trying to port an old Pascal DOS game to DOS C/C++. I am wondering if 
anyone is familar with the dos & crt Pascal units and whether there are 
C/C++ equivalent libraries. Maybe dos.c & crt.c?

Below lists names of variables, functions, types & weird interrupt 
procedures found in Pascal. Am wondering what can be done to get around them 
for use in C/C++.

dos.pas
crt.pas

---undefined identifiers---
'black'
'blue'
'clrscr'
'lightblue'
'lightcyan'
'lightgray'
'lightgreen'
'lightmagenta'
'lightred'
'mem'
'port'
'wherex'
'wherey'
'white'
'yellow'


---undefined functions---
'addr'
'blockread'
'delay'
'fillchar'
'fsearch'
'getintvec'
'gettime'
'gotoxy'
'hi'
'inline_'
'int_'
'intr'
'lo'
'ofs'
'seg'
'setintvec'
'settime'
'swap'
'textbackground'
'textcolor'
'window'


---unknown types---
Single
registers


---misc---
Port[$3C8] := reg;
l := port[$60];
port[$20] := $20;
Port[$43] := $B6;
ch := mem[seg(tex) + (let div 16): ofs(tex) + (let mod 16)];
procedure NewInt1C; Interrupt;
procedure NewInt08; Interrupt;