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SCP: Fix expression evaluation divide by zero, and avoid parameter substitution

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This allows bare the % character to to properly be the moduls operator and
avoids potential ambiguous variable insertions.
This commit is contained in:
Mark Pizzolato
2018-05-24 12:59:23 -07:00
parent 0daff9026d
commit c294787aed
2 changed files with 17 additions and 8 deletions
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23
scp.c
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@@ -555,10 +555,10 @@ int32 sim_brk_lnt = 0;
int32 sim_brk_ins = 0;
int32 sim_quiet = 0;
int32 sim_step = 0;
char *sim_sub_instr = NULL;
char *sim_sub_instr_buf = NULL;
size_t sim_sub_instr_size = 0;
size_t *sim_sub_instr_off = NULL;
char *sim_sub_instr = NULL; /* Copy of pre-substitution buffer contents */
char *sim_sub_instr_buf = NULL; /* Buffer address that substitutions were saved in */
size_t sim_sub_instr_size = 0; /* substitution buffer size */
size_t *sim_sub_instr_off = NULL; /* offsets in substitution buffer where original data started */
static double sim_time;
static uint32 sim_rtime;
static int32 noqueue_time;
@@ -4696,10 +4696,10 @@ else {
cptr = get_glyph (cptr, varname, '='); /* get environment variable name */
strlcpy (cbuf, cptr, sizeof(cbuf));
sim_trim_endspc (cbuf);
cptr = cbuf;
if (sim_switches & SWMASK ('S')) { /* Quote String argument? */
uint32 str_size;
cptr = cbuf;
get_glyph_quoted (cptr, cbuf, 0);
if (SCPE_OK != sim_decode_quoted_string (cbuf, (uint8 *)cbuf, &str_size))
return sim_messagef (SCPE_ARG, "Invalid quoted string: %s\n", cbuf);
@@ -4709,8 +4709,11 @@ else {
if (sim_switches & SWMASK ('A')) { /* Arithmentic Expression Evaluation argument? */
t_svalue val;
t_stat stat;
const char *eptr = cptr;
cptr = sim_eval_expression (cptr, &val, FALSE, &stat);
if ((cptr > sim_sub_instr_buf) && ((size_t)(cptr - sim_sub_instr_buf) < sim_sub_instr_size))
eptr = &sim_sub_instr[sim_sub_instr_off[cptr - sim_sub_instr_buf]]; /* get un-substituted string */
cptr = sim_eval_expression (eptr, &val, FALSE, &stat);
if (stat == SCPE_OK) {
sprintf (cbuf, "%ld", (long)val);
cptr = cbuf;
@@ -13469,12 +13472,16 @@ return factorx * factory;
static t_svalue _op_div (t_svalue divisor, t_svalue dividend)
{
return dividend / divisor;
if (divisor != 0)
return dividend / divisor;
return T_SVALUE_MAX;
}
static t_svalue _op_mod (t_svalue divisor, t_svalue dividend)
{
return dividend % divisor;
if (divisor != 0)
return dividend % divisor;
return 0;
}
static t_svalue _op_comp (t_svalue data, t_svalue unused)