Re: [Qemu-devel] [PATCH 04/14] timer: ds1338 clarify HOUR handling

[David Gibson <david@gibson.dropbear.id.au>]

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On Thu, Jul 05, 2018 at 11:19:51AM -0700, Michael Davidsaver wrote:
> Simplify and comment the translation between
> registers and struct tm.
> 
> Signed-off-by: Michael Davidsaver <mdavidsaver@gmail.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

although..

[snip]
> @@ -101,7 +105,9 @@ static void capture_current_time(DS1338State *s)
>          } else {
>              s->nvram[R_HOUR] = R_HOUR_SET12_MASK | R_HOUR_AMPM_MASK | to_bcd(tmp - 12);
>          }
> +
>      } else {

I'm not real fond of blank lines before the ends of blocks.

> +        /* 24 hour mode. */
>          s->nvram[R_HOUR] = to_bcd(now.tm_hour);
>      }
>      s->nvram[R_WDAY] = (now.tm_wday + s->wday_offset) % 7 + 1;
> @@ -178,14 +184,13 @@ static int ds1338_send(I2CSlave *i2c, uint8_t data)
>              break;
>          case R_HOUR:
>              if (FIELD_EX32(data, HOUR, SET12)) {
> -                int tmp = from_bcd(FIELD_EX32(data, HOUR, HOUR12));
> +                /* 12 hour (1-12) */
> +                /* read and wrap 1-12 -> 0-11 */
> +                now.tm_hour = from_bcd(FIELD_EX32(data, HOUR, HOUR12)) % 12u;
>                  if (FIELD_EX32(data, HOUR, AMPM)) {
> -                    tmp += 12;
> +                    now.tm_hour += 12;
>                  }
> -                if (tmp % 12 == 0) {
> -                    tmp -= 12;
> -                }
> -                now.tm_hour = tmp;
> +
>              } else {
>                  now.tm_hour = from_bcd(FIELD_EX32(data, HOUR, HOUR24));
>              }

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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