[v4,09/21] ipa: libipa: Provide Q4.8 FixedPoint support
diff mbox series

Message ID 20251114005428.90024-10-kieran.bingham@ideasonboard.com
State New
Headers show
Series
  • libipa: Introduce a Quantized type
Related show

Commit Message

Kieran Bingham Nov. 14, 2025, 12:54 a.m. UTC
Provide a FixedPoint Quantized type to support the Q4.8 format
representing values in the range [0 .. 15.9961] with a resolution of
1/256.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

---
This type is used by the Mali-C55 AWB Gains

 src/ipa/libipa/fixedpoint.cpp  | 9 +++++++++
 src/ipa/libipa/fixedpoint.h    | 2 ++
 test/ipa/libipa/fixedpoint.cpp | 5 +++++
 3 files changed, 16 insertions(+)

Patch
diff mbox series

diff --git a/src/ipa/libipa/fixedpoint.cpp b/src/ipa/libipa/fixedpoint.cpp
index a6f8ef351c32..03053668ed79 100644
--- a/src/ipa/libipa/fixedpoint.cpp
+++ b/src/ipa/libipa/fixedpoint.cpp
@@ -139,6 +139,15 @@  namespace ipa {
  * values in the range [0.0, 1.992] with a resolution of 1/128.
  */
 
+/**
+ * \typedef UQ4_8
+ * \brief 4.8 unsigned fixed-point quantizer
+ *
+ * A Quantized type using 4 bits for the integer part and 8 bits for the
+ * fractional part, stored in an unsigned 16-bit integer (\c uint16_t). Represents
+ * values in the range [0.0, 15.9961] with a resolution of 1/256.
+ */
+
 /**
  * \typedef Q5_4
  * \brief 5.4 signed fixed-point quantizer
diff --git a/src/ipa/libipa/fixedpoint.h b/src/ipa/libipa/fixedpoint.h
index 8f095210a918..05dd97e64f40 100644
--- a/src/ipa/libipa/fixedpoint.h
+++ b/src/ipa/libipa/fixedpoint.h
@@ -105,6 +105,8 @@  struct FixedPointQTraits {
 using Q1_7 = Quantized<FixedPointQTraits<1, 7, int8_t>>;
 using UQ1_7 = Quantized<FixedPointQTraits<1, 7, uint8_t>>;
 
+using UQ4_8 = Quantized<FixedPointQTraits<4, 8, uint16_t>>;
+
 using Q5_4 = Quantized<FixedPointQTraits<5, 4, int16_t>>;
 using UQ5_8 = Quantized<FixedPointQTraits<5, 8, uint16_t>>;
 
diff --git a/test/ipa/libipa/fixedpoint.cpp b/test/ipa/libipa/fixedpoint.cpp
index c830b5f05a19..f3773dfe6ad4 100644
--- a/test/ipa/libipa/fixedpoint.cpp
+++ b/test/ipa/libipa/fixedpoint.cpp
@@ -190,6 +190,11 @@  protected:
 		fails += quantizedCheck<Q4_7>(-0.4f, 0b1111'1001101, -0.398438f);	/* 0x7cd */
 		fails += quantizedCheck<Q4_7>(-1.4f, 0b1110'1001101, -1.39844f);	/* 0x74d */
 
+		/* UQ4_8(0 .. 15.9961)  Min: [0x0000:0] -- Max: [0x0fff:15.9961] Step:0.00390625 */
+		introduce<UQ4_8>("UQ4_8");
+		fails += quantizedCheck<UQ4_8>( 0.0f, 0b0000'00000000,  0.00f);
+		fails += quantizedCheck<UQ4_8>(16.0f, 0b1111'11111111, 15.9961f);
+
 		/* Q5_4(-16 .. 15.9375)  Min: [0x0100:-16] -- Max: [0x00ff:15.9375] Step:0.0625 */
 		introduce<Q5_4>("Q5_4");
 		fails += quantizedCheck<Q5_4>(-16.00f, 0b10000'0000, -16.00f);