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/* A module of ASYNCx.LIB version 1.20 */ 
 
#include "asyncdef.h" 
 
/*************************************************************** 
 Get one byte from the input buffer of the async port 
 associated with p. If a byte is found in the buffer, return 
 its value in the form of an integer (without sign extension). 
 If the buffer is empty, return a value of -1. 
***************************************************************/ 
int a_getc(register ASYNC *p) 
{byte c,*bp; 
 if (p) 
  {bp=p->ibuftail;        /* point to the next byte in the buffer */ 
   if (bp==p->ibufhead)   /* if there is nothing in the buffer,   */ 
     return -1;           /* return EOF.                          */ 
   c=(byte)(*bp++);       /* else, get the next byte.             */ 
   p->icount--;           /* adjust the byte count                */ 
   if (bp==p->ibufend)    /* wrap if necessary                    */ 
     bp=p->ibuf; 
   p->ibuftail=bp; 
   return (unsigned)c;    /* return the value retrieved           */ 
  } 
 return -1; 
} /* end of a_getc(p) */