drivers/gpu/drm/amd/display/dc/sspl/spl_fixpt31_32.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/amd/display/dc/sspl/spl_fixpt31_32.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/amd/display/dc/sspl/spl_fixpt31_32.c
Extension
.c
Size
11664 bytes
Lines
496
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (remainder >= arg2_value) {
				res_value |= 1;
				remainder -= arg2_value;
			}
		} while (--i != 0);
	}

	/* round up LSB */
	{
		unsigned long long summand = (remainder << 1) >= arg2_value;

		SPL_ASSERT(res_value <= (unsigned long long)LLONG_MAX - summand);

		res_value += summand;
	}

	res.value = (long long)res_value;

	if (arg1_negative ^ arg2_negative)
		res.value = -res.value;

	return res;
}

struct spl_fixed31_32 SPL_NAMESPACE(spl_fixpt_mul(
	struct spl_fixed31_32 arg1, struct spl_fixed31_32 arg2))
{
	struct spl_fixed31_32 res;

	bool arg1_negative = arg1.value < 0;
	bool arg2_negative = arg2.value < 0;

	unsigned long long arg1_value = arg1_negative ? -arg1.value : arg1.value;
	unsigned long long arg2_value = arg2_negative ? -arg2.value : arg2.value;

	unsigned long long arg1_int = GET_INTEGER_PART(arg1_value);
	unsigned long long arg2_int = GET_INTEGER_PART(arg2_value);

	unsigned long long arg1_fra = GET_FRACTIONAL_PART(arg1_value);
	unsigned long long arg2_fra = GET_FRACTIONAL_PART(arg2_value);

	unsigned long long tmp;

	res.value = arg1_int * arg2_int;

	SPL_ASSERT(res.value <= (long long)LONG_MAX);

	res.value <<= FIXED31_32_BITS_PER_FRACTIONAL_PART;

	tmp = arg1_int * arg2_fra;

	SPL_ASSERT(tmp <= (unsigned long long)(LLONG_MAX - res.value));

	res.value += tmp;

	tmp = arg2_int * arg1_fra;

	SPL_ASSERT(tmp <= (unsigned long long)(LLONG_MAX - res.value));

	res.value += tmp;

	tmp = arg1_fra * arg2_fra;

	tmp = (tmp >> FIXED31_32_BITS_PER_FRACTIONAL_PART) +
		(tmp >= (unsigned long long)spl_fixpt_half.value);

	SPL_ASSERT(tmp <= (unsigned long long)(LLONG_MAX - res.value));

	res.value += tmp;

	if (arg1_negative ^ arg2_negative)
		res.value = -res.value;

	return res;
}

struct spl_fixed31_32 SPL_NAMESPACE(spl_fixpt_sqr(struct spl_fixed31_32 arg))
{
	struct spl_fixed31_32 res;

	unsigned long long arg_value = abs_i64(arg.value);

	unsigned long long arg_int = GET_INTEGER_PART(arg_value);

	unsigned long long arg_fra = GET_FRACTIONAL_PART(arg_value);

	unsigned long long tmp;

	res.value = arg_int * arg_int;

Annotation

Implementation Notes