From b052050f3cf697baf22528012829c5539bf27ca0 Mon Sep 17 00:00:00 2001
From: cracyc <cracyc@users.noreply.github.com>
Date: Mon, 30 Dec 2019 17:21:46 -0600
Subject: [PATCH] i386: round before checking for exceptions (nw)

---
 src/devices/cpu/i386/x87ops.hxx | 12 ++++--------
 src/devices/machine/i8087.cpp   | 12 ++++--------
 2 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/src/devices/cpu/i386/x87ops.hxx b/src/devices/cpu/i386/x87ops.hxx
index 31789dbf0d7..1f2bdc4564a 100644
--- a/src/devices/cpu/i386/x87ops.hxx
+++ b/src/devices/cpu/i386/x87ops.hxx
@@ -2943,11 +2943,9 @@ void i386_device::x87_fst_m32real(uint8_t modrm)
 		value = ST(0);
 	}
 
+	uint32_t m32real = floatx80_to_float32(value);
 	if (x87_check_exceptions(true))
-	{
-		uint32_t m32real = floatx80_to_float32(value);
 		WRITE32(ea, m32real);
-	}
 
 	CYCLES(7);
 }
@@ -2970,11 +2968,9 @@ void i386_device::x87_fst_m64real(uint8_t modrm)
 		value = ST(0);
 	}
 
+	uint64_t m64real = floatx80_to_float64(value);
 	if (x87_check_exceptions(true))
-	{
-		uint64_t m64real = floatx80_to_float64(value);
 		WRITE64(ea, m64real);
-	}
 
 	CYCLES(8);
 }
@@ -3024,9 +3020,9 @@ void i386_device::x87_fstp_m32real(uint8_t modrm)
 		value = ST(0);
 	}
 
+	uint32_t m32real = floatx80_to_float32(value);
 	if (x87_check_exceptions(true))
 	{
-		uint32_t m32real = floatx80_to_float32(value);
 		WRITE32(ea, m32real);
 		x87_inc_stack();
 	}
@@ -3053,9 +3049,9 @@ void i386_device::x87_fstp_m64real(uint8_t modrm)
 
 
 	uint32_t ea = Getx87EA(modrm, 1);
+	uint64_t m64real = floatx80_to_float64(value);
 	if (x87_check_exceptions(true))
 	{
-		uint64_t m64real = floatx80_to_float64(value);
 		WRITE64(ea, m64real);
 		x87_inc_stack();
 	}
diff --git a/src/devices/machine/i8087.cpp b/src/devices/machine/i8087.cpp
index e203ee82d4e..b0b1bce08fc 100644
--- a/src/devices/machine/i8087.cpp
+++ b/src/devices/machine/i8087.cpp
@@ -2769,11 +2769,9 @@ void i8087_device::fst_m32real(u8 modrm)
 		value = ST(0);
 	}
 
+	u32 m32real = floatx80_to_float32(value);
 	if (check_exceptions(true))
-	{
-		u32 m32real = floatx80_to_float32(value);
 		WRITE32(ea, m32real);
-	}
 
 	CYCLES(7);
 }
@@ -2794,11 +2792,9 @@ void i8087_device::fst_m64real(u8 modrm)
 		value = ST(0);
 	}
 
+	u64 m64real = floatx80_to_float64(value);
 	if (check_exceptions(true))
-	{
-		uint64_t m64real = floatx80_to_float64(value);
 		WRITE64(ea, m64real);
-	}
 
 	CYCLES(8);
 }
@@ -2841,9 +2837,9 @@ void i8087_device::fstp_m32real(u8 modrm)
 		value = ST(0);
 	}
 
+	u32 m32real = floatx80_to_float32(value);
 	if (check_exceptions(true))
 	{
-		u32 m32real = floatx80_to_float32(value);
 		WRITE32(ea, m32real);
 		inc_stack();
 	}
@@ -2868,9 +2864,9 @@ void i8087_device::fstp_m64real(u8 modrm)
 
 
 	u32 ea = m_ea;
+	u64 m64real = floatx80_to_float64(value);
 	if (check_exceptions(true))
 	{
-		uint64_t m64real = floatx80_to_float64(value);
 		WRITE64(ea, m64real);
 		inc_stack();
 	}