Category : Assembly Language Source Code
Archive   : CUG292.ZIP
Filename : M00ADR.C

 
Output of file : M00ADR.C contained in archive : CUG292.ZIP

/* m00adr.c */

/*
* (C) Copyright 1989,1990
* All Rights Reserved
*
* Alan R. Baldwin
* 721 Berkeley St.
* Kent, Ohio 44240
*/

#include
#include
#include "asm.h"
#include "m6800.h"

int
addr(esp)
register struct expr *esp;
{
register c;

if ((c = getnb()) == '#') {
expr(esp, 0);
esp->e_mode = S_IMMED;
} else if (c == ',') {
esp->e_mode = S_INDX;
esp->e_flag = 0;
esp->e_addr = 0;
esp->e_base.e_ap = NULL;
if (admode(abx) != S_X)
aerr();
} else if (c == '*') {
expr(esp, 0);
esp->e_mode = S_DIR;
if (esp->e_addr & ~0xFF)
err('d');
if (more()) {
comma();
esp->e_mode = S_INDX;
if (admode(abx) != S_X)
aerr();
}
} else {
unget(c);
if ((esp->e_mode = admode(abx)) != 0) {
;
} else {
expr(esp, 0);
if (more()) {
comma();
esp->e_mode = S_INDX;
if (admode(abx) != S_X)
aerr();
if ((!esp->e_flag)
&& (esp->e_base.e_ap==NULL)
&& (esp->e_addr & ~0xFF))
aerr();
} else {
if ((!esp->e_flag)
&& (esp->e_base.e_ap==NULL)
&& !(esp->e_addr & ~0xFF)) {
esp->e_mode = S_DIR;
} else {
esp->e_mode = S_EXT;
}
}
}
}
return (esp->e_mode);
}

/*
* Enter admode() to search a specific addressing mode table
* for a match. Return the addressing value on a match or
* zero for no match.
*/
int
admode(sp)
register struct adsym *sp;
{
register char *ptr;
register int i;
unget(getnb());
i = 0;
while ( *(ptr = (char *) &sp[i]) ) {
if (srch(ptr)) {
return(sp[i].a_val);
}
i++;
}
return(0);
}

/*
* srch --- does string match ?
*/
int
srch(str)
register char *str;
{
register char *ptr;
ptr = ip;

#if CASE_SENSITIVE
while (*ptr && *str) {
if(*ptr != *str)
break;
ptr++;
str++;
}
if (*ptr == *str) {
ip = ptr;
return(1);
}
#else
while (*ptr && *str) {
if(ccase[*ptr] != ccase[*str])
break;
ptr++;
str++;
}
if (ccase[*ptr] == ccase[*str]) {
ip = ptr;
return(1);
}
#endif

if (!*str)
if (any(*ptr," \t\n,];")) {
ip = ptr;
return(1);
}
return(0);
}

/*
* any --- does str contain c?
*/
int
any(c,str)
char c, *str;
{
while (*str)
if(*str++ == c)
return(1);
return(0);
}

struct adsym abx[] = { /* a, b, or x registers */
"a", S_A,
"b", S_B,
"x", S_X,
"", 0x00
};