Re: [PATCH] drm: sti: remove redundant sign extensions

Hi Rasmus,

Thanks for the patch. I will integrated it in the next pull request for the sti driver.

BR Vincent

On 10/16/2015 03:14 PM, Rasmus Villemoes wrote:

arg is long int, so arg = (arg << 22) >> 22 makes the upper 22 bits of arg equal to bit 9 (or bit 41). But we then mask away all but bits 0-9, so this is entirely redundant.

Signed-off-by: Rasmus Villemoes linux@rasmusvillemoes.dk

gcc seems to be smart enough to realize this - the generated code is the same. This is thus just a tiny cleanup.

drivers/gpu/drm/sti/sti_awg_utils.c | 4 ---- 1 file changed, 4 deletions(-)

diff --git a/drivers/gpu/drm/sti/sti_awg_utils.c b/drivers/gpu/drm/sti/sti_awg_utils.c index 6029a2e3db1d..00d0698be9d3 100644 --- a/drivers/gpu/drm/sti/sti_awg_utils.c +++ b/drivers/gpu/drm/sti/sti_awg_utils.c @@ -65,7 +65,6 @@ static int awg_generate_instr(enum opcode opcode,

	mux = 0;
	data_enable = 0;

• 	arg = (arg << 22) >> 22;
  arg &= (0x3ff);
  break;
  

  case REPEAT:

@@ -77,14 +76,12 @@ static int awg_generate_instr(enum opcode opcode,

	mux = 0;
	data_enable = 0;

• 	arg = (arg << 22) >> 22;
  arg &= (0x3ff);
  break;
  

  case JUMP: mux = 0; data_enable = 0; arg |= 0x40; /* for jump instruction 7th bit is 1 */

• 	arg = (arg << 22) >> 22;
  arg &= 0x3ff;
  break;
  

  case STOP:

@@ -94,7 +91,6 @@ static int awg_generate_instr(enum opcode opcode, case RPTSET: case RPLSET: case HOLD:

• 	arg = (arg << 24) >> 24;
  arg &= (0x0ff);
  break;
  

  default: