IEEE 754 floating point completion code, and implementation of the

FP_C (Floating Point Control Quadword).

From ross@NetBSD.  Added a way to disable it with option NO_IEEE,
which appears on the ramdisks to save space.  This affects only
programs compiled with -mieee, and what it essentially does is
enabling infinities and NaNs, instead of generating SIGFPE on
division by zero, overflow, etc.
ok art, deraadt

1 files changed, 22 insertions, 1 deletions

diff --git a/sys/arch/alpha/include/proc.h b/sys/arch/alpha/include/proc.h
index fd698f6f9e1..dab1d4c78c0 100644
--- a/sys/arch/alpha/include/proc.h
+++ b/sys/arch/alpha/include/proc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: proc.h,v 1.7 2002/03/14 01:26:27 millert Exp $	*/
+/*	$OpenBSD: proc.h,v 1.8 2002/04/28 20:55:14 pvalchev Exp $	*/
 /*	$NetBSD: proc.h,v 1.2 1995/03/24 15:01:36 cgd Exp $	*/
 
 /*
@@ -45,7 +45,28 @@ struct mdproc {
 	struct mdbpt md_sstep[2];	/* two breakpoints for sstep */
 };
 
+/*
+ * md_flags usage
+ * --------------
+ * MDP_FPUSED
+ *      A largely unused bit indicating the presence of FPU history.
+ *      Cleared on exec. Set but not used by the fpu context switcher
+ *      itself.
+ * 
+ * MDP_FP_C
+ *      The architected FP Control word. It should forever begin at bit 1,
+ *      as the bits are AARM specified and this way it doesn't need to be
+ *      shifted.
+ * 
+ *      Until C99 there was never an IEEE 754 API, making most of the
+ *      standard useless.  Because of overlapping AARM, OSF/1, NetBSD, and
+ *      C99 API's, the use of the MDP_FP_C bits is defined variously in
+ *      ieeefp.h and fpu.h.
+ */
 #define	MDP_FPUSED	0x0001		/* Process used the FPU */
+#ifndef NO_IEEE
+#define	MDP_FP_C	0x7ffffe	/* Extended FP_C Quadword bits */
+#endif
 #define MDP_STEP1	0x0002		/* Single step normal */
 #define MDP_STEP2	0x0003		/* Single step branch */