diff options
| author | Gábor Stefanik <netrolller.3d@gmail.com> | 2009-08-26 20:51:24 +0200 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2009-08-28 14:40:52 -0400 |
| commit | d8fa338ee01e7de029d2441a8c2b9c5fbfeac82f (patch) | |
| tree | f744f9136f9f58136f03cd6e792d46a510474956 | |
| parent | ca9152e37f57259ca92486ca5753af16fd9155c6 (diff) | |
b43: LP-PHY: Fix and simplify Qdiv roundup
The Qdiv roundup routine is essentially a fixed-point
division algorithm, using only integer math.
However, the version in the specs had a major error
that has been recently fixed (a missing quotient++).
Replace Qdiv roundup with a rewritten, simplified version.
Signed-off-by: Gábor Stefanik <netrolller.3d@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
| -rw-r--r-- | drivers/net/wireless/b43/phy_lp.c | 19 |
1 files changed, 8 insertions, 11 deletions
diff --git a/drivers/net/wireless/b43/phy_lp.c b/drivers/net/wireless/b43/phy_lp.c index 7e70c078475..5306f2c66b3 100644 --- a/drivers/net/wireless/b43/phy_lp.c +++ b/drivers/net/wireless/b43/phy_lp.c @@ -1032,9 +1032,10 @@ static int lpphy_loopback(struct b43_wldev *dev) return index; } +/* Fixed-point division algorithm using only integer math. */ static u32 lpphy_qdiv_roundup(u32 dividend, u32 divisor, u8 precision) { - u32 quotient, remainder, rbit, roundup, tmp; + u32 quotient, remainder; if (divisor == 0) return 0; @@ -1042,20 +1043,16 @@ static u32 lpphy_qdiv_roundup(u32 dividend, u32 divisor, u8 precision) quotient = dividend / divisor; remainder = dividend % divisor; - rbit = divisor & 0x1; - roundup = (divisor >> 1) + rbit; - - while (precision != 0) { - tmp = remainder - roundup; + while (precision > 0) { quotient <<= 1; - if (remainder >= roundup) - remainder = (tmp << 1) + rbit; - else - remainder <<= 1; + if (remainder << 1 >= divisor) { + quotient++; + remainder = (remainder << 1) - divisor; + } precision--; } - if (remainder >= roundup) + if (remainder << 1 >= divisor) quotient++; return quotient; |