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    Subject[PATCH 01/22] tty: vt: make rgb_from_256() slighly more comprehensible
    Date
    * make the parameter unsigned, as it is expected to be unsigned,
    * make the computation easier to follow -- step-by-step, and
    * don't use 85 / 2 which is only a reduced form of 255 / 6 (by a factor
    3). Unlike the former, the latter can be understood.

    Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
    ---
    drivers/tty/vt/vt.c | 11 +++++++----
    1 file changed, 7 insertions(+), 4 deletions(-)

    diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
    index 65cd40cac96b..7d42f148559a 100644
    --- a/drivers/tty/vt/vt.c
    +++ b/drivers/tty/vt/vt.c
    @@ -1588,7 +1588,7 @@ static void default_attr(struct vc_data *vc)

    struct rgb { u8 r; u8 g; u8 b; };

    -static void rgb_from_256(int i, struct rgb *c)
    +static void rgb_from_256(unsigned int i, struct rgb *c)
    {
    if (i < 8) { /* Standard colours. */
    c->r = i&1 ? 0xaa : 0x00;
    @@ -1599,9 +1599,12 @@ static void rgb_from_256(int i, struct rgb *c)
    c->g = i&2 ? 0xff : 0x55;
    c->b = i&4 ? 0xff : 0x55;
    } else if (i < 232) { /* 6x6x6 colour cube. */
    - c->r = (i - 16) / 36 * 85 / 2;
    - c->g = (i - 16) / 6 % 6 * 85 / 2;
    - c->b = (i - 16) % 6 * 85 / 2;
    + i -= 16;
    + c->b = i % 6 * 255 / 6;
    + i /= 6;
    + c->g = i % 6 * 255 / 6;
    + i /= 6;
    + c->r = i * 255 / 6;
    } else /* Grayscale ramp. */
    c->r = c->g = c->b = i * 10 - 2312;
    }
    --
    2.43.0

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