diff options
Diffstat (limited to 'drivers/net/wireless/b43/phy_common.c')
| -rw-r--r-- | drivers/net/wireless/b43/phy_common.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/drivers/net/wireless/b43/phy_common.c b/drivers/net/wireless/b43/phy_common.c index 75b26e175e8..8f7d7eff2d8 100644 --- a/drivers/net/wireless/b43/phy_common.c +++ b/drivers/net/wireless/b43/phy_common.c @@ -421,3 +421,48 @@ void b43_phyop_switch_analog_generic(struct b43_wldev *dev, bool on) { b43_write16(dev, B43_MMIO_PHY0, on ? 0 : 0xF4); } + +/* http://bcm-v4.sipsolutions.net/802.11/PHY/Cordic */ +struct b43_c32 b43_cordic(int theta) +{ + u32 arctg[] = { 2949120, 1740967, 919879, 466945, 234379, 117304, + 58666, 29335, 14668, 7334, 3667, 1833, 917, 458, + 229, 115, 57, 29, }; + u8 i; + s32 tmp; + s8 signx = 1; + u32 angle = 0; + struct b43_c32 ret = { .i = 39797, .q = 0, }; + + while (theta > (180 << 16)) + theta -= (360 << 16); + while (theta < -(180 << 16)) + theta += (360 << 16); + + if (theta > (90 << 16)) { + theta -= (180 << 16); + signx = -1; + } else if (theta < -(90 << 16)) { + theta += (180 << 16); + signx = -1; + } + + for (i = 0; i <= 17; i++) { + if (theta > angle) { + tmp = ret.i - (ret.q >> i); + ret.q += ret.i >> i; + ret.i = tmp; + angle += arctg[i]; + } else { + tmp = ret.i + (ret.q >> i); + ret.q -= ret.i >> i; + ret.i = tmp; + angle -= arctg[i]; + } + } + + ret.i *= signx; + ret.q *= signx; + + return ret; +} |