On 22/03/2018 08:03, Su Hang wrote:
> When I was reading 'qemu/hw/timer/m48t59.c'(Line:328) and run with
> `make check-qtest-ppc`,
> I found when write an invalid value 0xc to address 0x1FFF,
> `from_bcd` return 12 instead of raising an exception(or error).
Each device probably has a different behavior when a wrong value is
written to a register that expects valid BCD. Therefore, if you want to
model that, you have to fix it in hw/timer/m48t59.c, not in from_bcd and
to_bcd.
However, note that anything that the guest does should never cause an
assertion.
Thanks,
Paolo
> """(qemu/hw/timer/m48t59.c)
> case 0x1FFF:
> case 0x07FF:
> /* year */
> tmp = from_bcd(val);
> if (tmp >= 0 && tmp <= 99) {
> """
>
>
> """(qemu/include/qemu/bcd.h)
> /* Convert a byte between binary and BCD. */
> static inline uint8_t to_bcd(uint8_t val)
> {
> return ((val / 10) << 4) | (val % 10);
> }
>
> static inline uint8_t from_bcd(uint8_t val)
> {
> return ((val >> 4) * 10) + (val & 0x0f);
> }
> """
>
> Su Hang
>
