From 087833951a00439a47fd83d4ce587e55e83acde9 Mon Sep 17 00:00:00 2001 From: Dmytro Laktyushkin Date: Wed, 18 Apr 2018 14:11:43 -0400 Subject: [PATCH 4458/5725] drm/amd/display: add fixed point fractional bit truncation function Signed-off-by: Dmytro Laktyushkin Reviewed-by: Tony Cheng Acked-by: Harry Wentland --- drivers/gpu/drm/amd/display/include/fixed31_32.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/gpu/drm/amd/display/include/fixed31_32.h b/drivers/gpu/drm/amd/display/include/fixed31_32.h index ebfd33e..61f11e2 100644 --- a/drivers/gpu/drm/amd/display/include/fixed31_32.h +++ b/drivers/gpu/drm/amd/display/include/fixed31_32.h @@ -496,4 +496,21 @@ unsigned int dc_fixpt_clamp_u0d10(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 -- 2.7.4