NetBoot/vasm-1/cond.c
2020-06-20 09:33:04 +08:00

86 lines
1.5 KiB
C

/* cond.c - conditional assembly support routines */
/* (c) in 2015 by Frank Wille */
#include "vasm.h"
int clev; /* conditional level */
static char cond[MAXCONDLEV+1];
static char *condsrc[MAXCONDLEV+1];
static int condline[MAXCONDLEV+1];
static int ifnesting;
/* initialize conditional assembly */
void cond_init(void)
{
cond[0] = 1;
clev = ifnesting = 0;
}
/* return true, when current level allows assembling */
int cond_state(void)
{
return cond[clev];
}
/* ensures that all conditional block are closed at the end of the source */
void cond_check(void)
{
if (clev > 0)
general_error(66,condsrc[clev],condline[clev]); /* "endc/endif missing */
}
/* establish a new level of conditional assembly */
void cond_if(char flag)
{
if (++clev >= MAXCONDLEV)
general_error(65,clev); /* nesting depth exceeded */
cond[clev] = flag;
condsrc[clev] = cur_src->name;
condline[clev] = cur_src->line;
}
/* handle skipped if statement */
void cond_skipif(void)
{
ifnesting++;
}
/* handle else statement after skipped if-branch */
void cond_else(void)
{
if (ifnesting == 0)
cond[clev] = 1;
}
/* handle else statement after assembled if-branch */
void cond_skipelse(void)
{
if (clev > 0)
cond[clev] = 0;
else
general_error(63); /* else without if */
}
/* handle end-if statement */
void cond_endif(void)
{
if (ifnesting == 0) {
if (clev > 0)
clev--;
else
general_error(64); /* unexpected endif without if */
}
else /* the whole conditional block was ignored */
ifnesting--;
}