Assertions in design by contract: Difference between revisions
Content added Content deleted
Puppydrum64 (talk | contribs) |
Puppydrum64 (talk | contribs) |
||
| Line 7: | Line 7: | ||
Show in the program language of your choice an example of the use of assertions as a form of documentation. |
Show in the program language of your choice an example of the use of assertions as a form of documentation. |
||
<br><br> |
<br><br> |
||
=={{header|68000 Assembly}}== |
|||
Error handlers are referred to as *traps* on the 68000, and they can be triggered automatically (such as attempting to divide by zero) and by command (such as for if overflow has occurred.) |
|||
Precondition example: |
|||
<lang 68000devpac> DIVU D3,D2 ;this will cause a jump to Trap 4 if D3 = 0.</lang> |
|||
Postcondition examples: |
|||
<lang 68000devpac> ADD.L D4,D5 |
|||
TRAPV ;no overflow is expected, so if it occurs call the relevant trap.</lang> |
|||
<lang 68000devpac> LSL.W #8,D2 ;shift D2 left 8 bits. |
|||
bcc continue ;if carry clear, we're good. |
|||
trap 9 ;otherwise call trap 9, which has arbitrarily been defined to handle unexpected carries after a bit shift. |
|||
continue: ;the program resumes normally after this point |
|||
</lang> |
|||
=={{header|Ada}}== |
=={{header|Ada}}== |
||