From: Gareth Hughes <gareth@valinux.com>
Date: Sun, 13 May 2001 18:55:15 +0000 (+0000)
Subject: Fix long-standing FP exception bug in _mesa_x86_cliptest_points4().
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=53e4ebd4e36c0ae462d71c87cda3533f9d001324;p=mesa.git

Fix long-standing FP exception bug in _mesa_x86_cliptest_points4().
---

diff --git a/src/mesa/x86/x86.c b/src/mesa/x86/x86.c
index ddcfe86a752..b2b442c87e2 100644
--- a/src/mesa/x86/x86.c
+++ b/src/mesa/x86/x86.c
@@ -1,4 +1,4 @@
-/* $Id: x86.c,v 1.21 2001/03/30 14:44:43 gareth Exp $ */
+/* $Id: x86.c,v 1.22 2001/05/13 18:55:15 gareth Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -85,7 +85,6 @@ void _mesa_init_x86_transform_asm( void )
    ASSIGN_XFORM_GROUP( x86, 3 );
    ASSIGN_XFORM_GROUP( x86, 4 );
 
-   /* XXX this function has been found to cause FP overflow exceptions */
    _mesa_clip_tab[4] = _mesa_x86_cliptest_points4;
    _mesa_clip_np_tab[4] = _mesa_x86_cliptest_points4_np;
 
diff --git a/src/mesa/x86/x86_cliptest.S b/src/mesa/x86/x86_cliptest.S
index f228274dedf..76f34d5d5c2 100644
--- a/src/mesa/x86/x86_cliptest.S
+++ b/src/mesa/x86/x86_cliptest.S
@@ -1,4 +1,4 @@
-/* $Id: x86_cliptest.S,v 1.6 2001/03/28 20:44:44 gareth Exp $ */
+/* $Id: x86_cliptest.S,v 1.7 2001/05/13 18:55:15 gareth Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -149,7 +149,12 @@ LLBL( ctp4_clip_table_ready ):
 ALIGNTEXT16
 LLBL( ctp4_top ):
 
-	FLD1			/* F3 */
+	MOV_L( SRC(3), ECX )
+	FLD1				/* F3 */
+
+	TEST_L( ECX, ECX )		/* GH: If src[3] is zero, abort */
+	JZ( LLBL( ctp4_noproj ) )
+
 	FDIV_S( SRC(3) )
 
 	MOV_L( SRC(3), EBP )
@@ -198,7 +203,15 @@ LLBL( ctp4_top ):
 
 	JZ( LLBL( ctp4_proj ) )
 
-	FSTP( ST(0) )			/* */
+LLBL( ctp4_noproj ):
+
+	FLDZ				/* F0 F3 */
+
+	FST_S( DST(0) )			/* F0 F3 */
+	FST_S( DST(1) )			/* F0 F3 */
+	FSTP_S( DST(2) )		/* F3 */
+	FSTP_S( DST(3) )		/* */
+
 	JMP( LLBL( ctp4_next ) )
 
 LLBL( ctp4_proj ):