drm/amd/display: add fixed point fractional bit truncation function

Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Dmytro Laktyushkin 2018-04-18 14:11:43 -04:00 committed by Alex Deucher
parent e8838df1cb
commit ab9c2062d9
1 changed files with 17 additions and 0 deletions

View File

@ -496,4 +496,21 @@ unsigned int dc_fixpt_clamp_u0d10(struct fixed31_32 arg);
int dc_fixpt_s4d19(struct fixed31_32 arg); int dc_fixpt_s4d19(struct fixed31_32 arg);
static inline struct fixed31_32 dc_fixpt_truncate(struct fixed31_32 arg, unsigned int frac_bits)
{
bool negative = arg.value < 0;
if (frac_bits >= FIXED31_32_BITS_PER_FRACTIONAL_PART) {
ASSERT(frac_bits == FIXED31_32_BITS_PER_FRACTIONAL_PART);
return arg;
}
if (negative)
arg.value = -arg.value;
arg.value &= (~0LL) << (FIXED31_32_BITS_PER_FRACTIONAL_PART - frac_bits);
if (negative)
arg.value = -arg.value;
return arg;
}
#endif #endif