Commit a838834b authored by Alex Deucher's avatar Alex Deucher
Browse files

drm: fix 64 bit drm fixed point helpers 



Sign bit wasn't handled properly and a small typo.

Thanks to Christian for helping me sort this out.

Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 42a21826

include/drm/drm_fixed.h

+7 −7
Original line number Diff line number Diff line
@@ -84,12 +84,12 @@ static inline int drm_fixp2int(int64_t a) 
	return ((s64)a) >> DRM_FIXED_POINT;

}



static inline s64 drm_fixp_msbset(int64_t a)

static inline unsigned drm_fixp_msbset(int64_t a)

{

	unsigned shift, sign = (a >> 63) & 1;



	for (shift = 62; shift > 0; --shift)

		if ((a >> shift) != sign)

		if (((a >> shift) & 1) != sign)

			return shift;



	return 0;
@@ -100,9 +100,9 @@ static inline s64 drm_fixp_mul(s64 a, s64 b) 
	unsigned shift = drm_fixp_msbset(a) + drm_fixp_msbset(b);

	s64 result;



	if (shift > 63) {

		shift = shift - 63;

		a >>= shift >> 1;

	if (shift > 61) {

		shift = shift - 61;

		a >>= (shift >> 1) + (shift & 1);

		b >>= shift >> 1;

	} else

		shift = 0;
@@ -120,7 +120,7 @@ static inline s64 drm_fixp_mul(s64 a, s64 b) 


static inline s64 drm_fixp_div(s64 a, s64 b)

{

	unsigned shift = 63 - drm_fixp_msbset(a);

	unsigned shift = 62 - drm_fixp_msbset(a);

	s64 result;



	a <<= shift;
@@ -154,7 +154,7 @@ static inline s64 drm_fixp_exp(s64 x) 
	}



	if (x < 0)

		sum = drm_fixp_div(1, sum);

		sum = drm_fixp_div(DRM_FIXED_ONE, sum);



	return sum;

}