From aecf865c2c77da435d5f351b7eaeb49d200944a4 Mon Sep 17 00:00:00 2001
From: TomW <TomW@localhost>
Date: Mon, 17 Nov 2014 20:23:29 +0000
Subject: [PATCH] Re-added FCOMPP 80387 detection hack accidentally removed in
 FPU reorganisation.

---
 src/x87_ops_arith.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/x87_ops_arith.h b/src/x87_ops_arith.h
index 65c5608..d2985e1 100644
--- a/src/x87_ops_arith.h
+++ b/src/x87_ops_arith.h
@@ -159,8 +159,12 @@ static int opFCOMPP(uint32_t fetchdat)
         pc++;
         if (fplog) pclog("FCOMPP\n");
         npxs &= ~(C0|C2|C3);
-        if (ST(0) == ST(1))     npxs |= C3;
-        else if (ST(0) < ST(1)) npxs |= C0;
+        if (*(uint64_t *)&ST(0) == ((uint64_t)1 << 63) && *(uint64_t *)&ST(1) == 0)
+                npxs |= C0; /*Nasty hack to fix 80387 detection*/
+        else if (ST(0) == ST(1))
+                npxs |= C3;
+        else if (ST(0) < ST(1))
+                npxs |= C0;
         x87_pop();
         x87_pop();
         CLOCK_CYCLES(4);