1 files changed, 151 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/sspl/spl_custom_float.c b/drivers/gpu/drm/amd/display/dc/sspl/spl_custom_float.c
new file mode 100644
index 000000000000..be2f34d034c5
--- /dev/null
+++ b/drivers/gpu/drm/amd/display/dc/sspl/spl_custom_float.c
@@ -0,0 +1,151 @@
+// SPDX-License-Identifier: MIT
+//
+// Copyright 2024 Advanced Micro Devices, Inc.
+
+#include "spl_debug.h"
+#include "spl_custom_float.h"
+
+static bool spl_build_custom_float(struct spl_fixed31_32 value,
+			       const struct spl_custom_float_format *format,
+			       bool *negative,
+			       uint32_t *mantissa,
+			       uint32_t *exponenta)
+{
+	uint32_t exp_offset = (1 << (format->exponenta_bits - 1)) - 1;
+
+	const struct spl_fixed31_32 mantissa_constant_plus_max_fraction =
+		spl_fixpt_from_fraction((1LL << (format->mantissa_bits + 1)) - 1,
+				       1LL << format->mantissa_bits);
+
+	struct spl_fixed31_32 mantiss;
+
+	if (spl_fixpt_eq(value, spl_fixpt_zero)) {
+		*negative = false;
+		*mantissa = 0;
+		*exponenta = 0;
+		return true;
+	}
+
+	if (spl_fixpt_lt(value, spl_fixpt_zero)) {
+		*negative = format->sign;
+		value = spl_fixpt_neg(value);
+	} else {
+		*negative = false;
+	}
+
+	if (spl_fixpt_lt(value, spl_fixpt_one)) {
+		uint32_t i = 1;
+
+		do {
+			value = spl_fixpt_shl(value, 1);
+			++i;
+		} while (spl_fixpt_lt(value, spl_fixpt_one));
+
+		--i;
+
+		if (exp_offset <= i) {
+			*mantissa = 0;
+			*exponenta = 0;
+			return true;
+		}
+
+		*exponenta = exp_offset - i;
+	} else if (spl_fixpt_le(mantissa_constant_plus_max_fraction, value)) {
+		uint32_t i = 1;
+
+		do {
+			value = spl_fixpt_shr(value, 1);
+			++i;
+		} while (spl_fixpt_lt(mantissa_constant_plus_max_fraction, value));
+
+		*exponenta = exp_offset + i - 1;
+	} else {
+		*exponenta = exp_offset;
+	}
+
+	mantiss = spl_fixpt_sub(value, spl_fixpt_one);
+
+	if (spl_fixpt_lt(mantiss, spl_fixpt_zero) ||
+	    spl_fixpt_lt(spl_fixpt_one, mantiss))
+		mantiss = spl_fixpt_zero;
+	else
+		mantiss = spl_fixpt_shl(mantiss, format->mantissa_bits);
+
+	*mantissa = spl_fixpt_floor(mantiss);
+
+	return true;
+}
+
+static bool spl_setup_custom_float(const struct spl_custom_float_format *format,
+			       bool negative,
+			       uint32_t mantissa,
+			       uint32_t exponenta,
+			       uint32_t *result)
+{
+	uint32_t i = 0;
+	uint32_t j = 0;
+	uint32_t value = 0;
+
+	/* verification code:
+	 * once calculation is ok we can remove it
+	 */
+
+	const uint32_t mantissa_mask =
+		(1 << (format->mantissa_bits + 1)) - 1;
+
+	const uint32_t exponenta_mask =
+		(1 << (format->exponenta_bits + 1)) - 1;
+
+	if (mantissa & ~mantissa_mask) {
+		SPL_BREAK_TO_DEBUGGER();
+		mantissa = mantissa_mask;
+	}
+
+	if (exponenta & ~exponenta_mask) {
+		SPL_BREAK_TO_DEBUGGER();
+		exponenta = exponenta_mask;
+	}
+
+	/* end of verification code */
+
+	while (i < format->mantissa_bits) {
+		uint32_t mask = 1 << i;
+
+		if (mantissa & mask)
+			value |= mask;
+
+		++i;
+	}
+
+	while (j < format->exponenta_bits) {
+		uint32_t mask = 1 << j;
+
+		if (exponenta & mask)
+			value |= mask << i;
+
+		++j;
+	}
+
+	if (negative && format->sign)
+		value |= 1 << (i + j);
+
+	*result = value;
+
+	return true;
+}
+
+bool spl_convert_to_custom_float_format(struct spl_fixed31_32 value,
+				    const struct spl_custom_float_format *format,
+				    uint32_t *result)
+{
+	uint32_t mantissa;
+	uint32_t exponenta;
+	bool negative;
+
+	return spl_build_custom_float(value, format, &negative, &mantissa, &exponenta) &&
+				  spl_setup_custom_float(format,
+						     negative,
+						     mantissa,
+						     exponenta,
+						     result);
+}