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IAR Embedded Workbench for RISC-V 3.40

SEC-DIV-0-compare-after

In this section:
Synopsis

After a successful comparison with 0, a variable is used as a divisor.

Enabled by default

Yes

Severity/Certainty

Medium/High

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Full description

A variable is compared to 0, then used as a divisor before being written to. The comparison implies that the variable's value is 0 for all following statements. Using it as a divisor afterwards causes a 'divide by zero' runtime error. This check is identical to ATH-div-0-cmp-aft, MISRAC2004-1.2_e, MISRAC2012-Rule-1.3_c, CERT-INT33-C_b.

Coding standards
CERT INT33-C

Ensure that division and modulo operations do not result in divide-by-zero errors

CWE 369

Divide By Zero

MISRA C:2004 1.2

(Required) No reliance shall be placed on undefined or unspecified behavior.

MISRA C:2012 Rule-1.3

(Required) There shall be no occurrence of undefined or critical unspecified behaviour

Code examples

The following code example fails the check and will give a warning:

#include <stdlib.h>
int foo(void)
{
  int a = 20;
  int p = rand();

  if (p == 0)   /* p is 0 */
    a = 34 / p;

  return a;
}

The following code example passes the check and will not give a warning about this issue:

#include <stdlib.h>
int foo(void)
{
  int a = 20;
  int p = rand();

  if (p != 0)   /* p is not 0 */
    a = 34 / p;

  return a;
}