From 48bca2af5a51ed942fb623d1b9479d2d63bd42ea Mon Sep 17 00:00:00 2001
From: GitHubProUser67 <127040195+GitHubProUser67@users.noreply.github.com>
Date: Sun, 19 Jan 2025 23:17:43 +0100
Subject: [PATCH] [Soft-Float] - Fixes Itof accuracy.

The PS2 FP Unit behave differently if exponent is less than 158, we emulate this now.

Expect some AI improvements, if any.
---
 pcsx2/PS2Float.cpp | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/pcsx2/PS2Float.cpp b/pcsx2/PS2Float.cpp
index 3bd0c5ede1b5f..65977af69d219 100644
--- a/pcsx2/PS2Float.cpp
+++ b/pcsx2/PS2Float.cpp
@@ -468,18 +468,17 @@ PS2Float PS2Float::Itof(s32 complement, s32 f1)
 
 	s32 resExponent;
 
+	bool negative = f1 < 0;
+
 	if (f1 == -2147483648)
 	{
-		// special case
-		resExponent = 158 - complement;
-
-		if (resExponent >= 0)
-			return PS2Float(true, (u8)resExponent, 0);
-
-		return PS2Float(0);
+		if (complement <= 0)
+			// special case
+			return PS2Float(0xcf000000);
+		else
+			f1 = 2147483647;
 	}
 
-	bool negative = f1 < 0;
 	s32 u = std::abs(f1);
 
 	s32 shifts;
@@ -500,7 +499,9 @@ PS2Float PS2Float::Itof(s32 complement, s32 f1)
 
 	resExponent = BIAS + MANTISSA_BITS - shifts - complement;
 
-	if (resExponent >= 0)
+	if (resExponent >= 158)
+		return negative ? PS2Float(0xcf000000) : PS2Float(0x4f000000);
+	else if (resExponent >= 0)
 		return PS2Float(negative, (u8)resExponent, (u32)u);
 
 	return PS2Float(0);