From c1ec2ddb6399666fb84143388c8e3b1ad77a0281 Mon Sep 17 00:00:00 2001
From: rmg-x <git@rmgx.io>
Date: Sat, 9 Nov 2024 14:25:05 -0600
Subject: [PATCH] AK: Add 16-bit float type

---
 AK/Format.cpp           |  7 +++++++
 AK/Format.h             | 11 +++++++++++
 AK/NumericLimits.h      | 11 +++++++++++
 AK/StdLibExtraDetails.h |  2 ++
 AK/Types.h              |  3 +++
 5 files changed, 34 insertions(+)

diff --git a/AK/Format.cpp b/AK/Format.cpp
index 8d6f14cbc8d..27c30661b01 100644
--- a/AK/Format.cpp
+++ b/AK/Format.cpp
@@ -1012,6 +1012,13 @@ ErrorOr<void> Formatter<long double>::format(FormatBuilder& builder, long double
     return builder.put_f80(value, base, upper_case, m_use_separator, m_align, m_width.value(), m_precision.value(), m_fill, m_sign_mode, real_number_display_mode);
 }
 
+ErrorOr<void> Formatter<f16>::format(FormatBuilder& builder, f16 value)
+{
+    // FIXME: Create a proper put_f16() implementation
+    Formatter<double> formatter { *this };
+    return TRY(formatter.format(builder, static_cast<double>(value)));
+}
+
 ErrorOr<void> Formatter<double>::format(FormatBuilder& builder, double value)
 {
     u8 base;
diff --git a/AK/Format.h b/AK/Format.h
index 695522d3453..b4df3bb0e69 100644
--- a/AK/Format.h
+++ b/AK/Format.h
@@ -551,6 +551,17 @@ struct Formatter<long double> : StandardFormatter {
     ErrorOr<void> format(FormatBuilder&, long double value);
 };
 
+template<>
+struct Formatter<f16> : StandardFormatter {
+    Formatter() = default;
+    explicit Formatter(StandardFormatter formatter)
+        : StandardFormatter(formatter)
+    {
+    }
+
+    ErrorOr<void> format(FormatBuilder&, f16 value);
+};
+
 template<>
 struct Formatter<nullptr_t> : Formatter<FlatPtr> {
     ErrorOr<void> format(FormatBuilder& builder, nullptr_t)
diff --git a/AK/NumericLimits.h b/AK/NumericLimits.h
index 8279dfe6f54..c36f05e1e89 100644
--- a/AK/NumericLimits.h
+++ b/AK/NumericLimits.h
@@ -143,6 +143,17 @@ struct NumericLimits<long double> {
     static constexpr size_t digits() { return __LDBL_MANT_DIG__; }
 };
 
+template<>
+struct NumericLimits<f16> {
+    static constexpr f16 lowest() { return -__FLT16_MAX__; }
+    static constexpr f16 min_normal() { return __FLT16_MIN__; }
+    static constexpr f16 min_denormal() { return __FLT16_DENORM_MIN__; }
+    static constexpr f16 max() { return __FLT16_MAX__; }
+    static constexpr f16 epsilon() { return __FLT16_EPSILON__; }
+    static constexpr bool is_signed() { return true; }
+    static constexpr size_t digits() { return __FLT16_MANT_DIG__; }
+};
+
 }
 
 #if USING_AK_GLOBALLY
diff --git a/AK/StdLibExtraDetails.h b/AK/StdLibExtraDetails.h
index 15af899a32e..4964cda9d0a 100644
--- a/AK/StdLibExtraDetails.h
+++ b/AK/StdLibExtraDetails.h
@@ -350,6 +350,8 @@ template<>
 inline constexpr bool __IsFloatingPoint<double> = true;
 template<>
 inline constexpr bool __IsFloatingPoint<long double> = true;
+template<>
+inline constexpr bool __IsFloatingPoint<f16> = true;
 
 template<typename T>
 inline constexpr bool IsFloatingPoint = __IsFloatingPoint<RemoveCV<T>>;
diff --git a/AK/Types.h b/AK/Types.h
index 84e24a0508c..a5bbc0846a8 100644
--- a/AK/Types.h
+++ b/AK/Types.h
@@ -17,6 +17,9 @@ using i32 = __INT32_TYPE__;
 using i16 = __INT16_TYPE__;
 using i8 = __INT8_TYPE__;
 
+using f16 = _Float16;
+static_assert(__FLT16_MANT_DIG__ == 11 && __FLT16_MAX_EXP__ == 16);
+
 using f32 = float;
 static_assert(__FLT_MANT_DIG__ == 24 && __FLT_MAX_EXP__ == 128);