On Monday, February 04, 2013 5:59 AM, Dan Carpenter wrote: > On Sun, Feb 03, 2013 at 10:54:37PM +0100, Peter Huewe wrote: >> Since data can only be 0x0000, 0x0035 or 0x0048 we can simply skip the >> bit shifting and masking as data & 0xFF is always equal to data and >> data & 0xFF00 is always 0. >> So we simply use data and 0 directly and save the assignment. >> >> Signed-off-by: Peter Huewe <peterhuewe@xxxxxx> >> --- >> drivers/staging/xgifb/vb_setmode.c | 6 ++---- >> 1 files changed, 2 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/staging/xgifb/vb_setmode.c b/drivers/staging/xgifb/vb_setmode.c >> index 6f366f4..1ff1178 100644 >> --- a/drivers/staging/xgifb/vb_setmode.c >> +++ b/drivers/staging/xgifb/vb_setmode.c >> @@ -1083,10 +1083,8 @@ static void XGI_SetCRT1ModeRegs(struct xgi_hw_device_info *HwDeviceExtension, >> data = 0x0048; >> } >> >> - data2 = data & 0x00FF; >> - xgifb_reg_and_or(pVBInfo->P3d4, 0x19, 0xFF, data2); >> - data2 = (data & 0xFF00) >> 8; >> - xgifb_reg_and_or(pVBInfo->P3d4, 0x19, 0xFC, data2); >> + xgifb_reg_and_or(pVBInfo->P3d4, 0x19, 0xFF, data); >> + xgifb_reg_and_or(pVBInfo->P3d4, 0x19, 0xFC, 0); > > This patch is fine. > > This is a fairly common pattern where people do: > > write_a_char(data & 0xff); > write_a_char((data >> 8) & 0xff); > > It feels there should be a macro to do the shift and mask but I'm > not sure what it would look like. How about... #define LOBYTE(x) ((x) & 0xff) #define HIBYTE(x) (((x) >> 8) & 0xff) And for completeness... #define LOWORD ((x) & 0xffff) #define HIWORD (((x) >> 16) & 0xffff) There are a couple uses of these defines in the kernel already. sound/synth/emux/emux_synth.c also has LO_BYTE and HI_BYTE that do the same thing. Of course these are probably not endian safe. Regards, Hartley _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
