Module Name: src
Committed By: matt
Date: Sun Jun 12 05:44:36 UTC 2011
Modified Files:
src/lib/libc/arch/alpha/gen: __setjmp14.S flt_rounds.c fpgetround.c
fpsetround.c
Log Message:
Use excb before and after the mt_fpcr/mf_fpcr instructions as specified
in the alpha ARM 4.7.8.1 (Accessing the FPCR):
Because Alpha floating-point hardware can overlap the execution of
a number of floating-point instructions, accessing the FPCR must
be synchronized with other floating-point instructions. An EXCB
instruction must be issued both prior to and after accessing the
FPCR to ensure that the FPCR access is synchronized with the
execution of previous and subsequent floating-point instructions;
otherwise synchronization is not ensured.
Use unions to convert between double and uint64_t to avoid casting.
To generate a diff of this commit:
cvs rdiff -u -r1.4 -r1.5 src/lib/libc/arch/alpha/gen/__setjmp14.S
cvs rdiff -u -r1.8 -r1.9 src/lib/libc/arch/alpha/gen/flt_rounds.c
cvs rdiff -u -r1.9 -r1.10 src/lib/libc/arch/alpha/gen/fpgetround.c
cvs rdiff -u -r1.10 -r1.11 src/lib/libc/arch/alpha/gen/fpsetround.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/arch/alpha/gen/__setjmp14.S
diff -u src/lib/libc/arch/alpha/gen/__setjmp14.S:1.4 src/lib/libc/arch/alpha/gen/__setjmp14.S:1.5
--- src/lib/libc/arch/alpha/gen/__setjmp14.S:1.4 Sun Mar 21 18:04:27 2004
+++ src/lib/libc/arch/alpha/gen/__setjmp14.S Sun Jun 12 05:44:36 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: __setjmp14.S,v 1.4 2004/03/21 18:04:27 matt Exp $ */
+/* $NetBSD: __setjmp14.S,v 1.5 2011/06/12 05:44:36 matt Exp $ */
/*
* Copyright (c) 1994, 1995 Carnegie-Mellon University.
@@ -96,7 +96,9 @@
stt fs5, (7*8 + SC_FPREGS)(a0)
stt fs6, (8*8 + SC_FPREGS)(a0)
stt fs7, (9*8 + SC_FPREGS)(a0)
+ excb /* required 4.7.8.1 Alpha ARM */
mf_fpcr ft0 /* get FP control reg */
+ excb /* required 4.7.8.1 Alpha ARM */
stt ft0, SC_FPCR(a0) /* and store it in sc_fpcr */
stq zero, SC_FP_CONTROL(a0) /* FP software control XXX */
stq zero, (SC_RESERVED + 0*8)(a0) /* sc_reserved[0] */
Index: src/lib/libc/arch/alpha/gen/flt_rounds.c
diff -u src/lib/libc/arch/alpha/gen/flt_rounds.c:1.8 src/lib/libc/arch/alpha/gen/flt_rounds.c:1.9
--- src/lib/libc/arch/alpha/gen/flt_rounds.c:1.8 Sat Dec 24 23:10:08 2005
+++ src/lib/libc/arch/alpha/gen/flt_rounds.c Sun Jun 12 05:44:36 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: flt_rounds.c,v 1.8 2005/12/24 23:10:08 perry Exp $ */
+/* $NetBSD: flt_rounds.c,v 1.9 2011/06/12 05:44:36 matt Exp $ */
/*
* Copyright (c) 1995 Christopher G. Demetriou
@@ -36,29 +36,33 @@
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: flt_rounds.c,v 1.8 2005/12/24 23:10:08 perry Exp $");
+__RCSID("$NetBSD: flt_rounds.c,v 1.9 2011/06/12 05:44:36 matt Exp $");
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
+#include <machine/ieeefp.h>
#include <machine/float.h>
-static const int map[] = {
- 0, /* round to zero */
- 3, /* round to negative infinity */
- 1, /* round to nearest */
- 2 /* round to positive infinity */
-};
+/*
+ * These come from <float.h> defintion
+ */
+#define FLT_ROUND_MAP \
+ ( (0 << (FP_RZ*2)) /* round to zero */ \
+ | (1 << (FP_RN*2)) /* round to nearest */ \
+ | (3 << (FP_RM*2)) /* round to negative infinity */ \
+ | (2 << (FP_RP*2))) /* round to positive infinity */
int
-__flt_rounds()
+__flt_rounds(void)
{
- double fpcrval;
- u_int64_t old;
+ union {
+ double d;
+ uint64_t u64;
+ } fpcrval;
+ uint64_t old;
- __asm("trapb");
- __asm("mf_fpcr %0" : "=f" (fpcrval));
- __asm("trapb");
- old = *(u_int64_t *)(void *)&fpcrval;
+ __asm("excb; mf_fpcr %0; excb" : "=f" (fpcrval.d));
+ old = (fpcrval.u64 >> 58) & 3;
- return map[(old >> 58) & 0x3];
+ return (FLT_ROUND_MAP >> (old << 1)) & 3;
}
Index: src/lib/libc/arch/alpha/gen/fpgetround.c
diff -u src/lib/libc/arch/alpha/gen/fpgetround.c:1.9 src/lib/libc/arch/alpha/gen/fpgetround.c:1.10
--- src/lib/libc/arch/alpha/gen/fpgetround.c:1.9 Sat Dec 24 23:10:08 2005
+++ src/lib/libc/arch/alpha/gen/fpgetround.c Sun Jun 12 05:44:36 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: fpgetround.c,v 1.9 2005/12/24 23:10:08 perry Exp $ */
+/* $NetBSD: fpgetround.c,v 1.10 2011/06/12 05:44:36 matt Exp $ */
/*
* Copyright (c) 1995 Christopher G. Demetriou
@@ -36,7 +36,7 @@
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: fpgetround.c,v 1.9 2005/12/24 23:10:08 perry Exp $");
+__RCSID("$NetBSD: fpgetround.c,v 1.10 2011/06/12 05:44:36 matt Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
@@ -49,13 +49,14 @@
#endif
fp_rnd
-fpgetround()
+fpgetround(void)
{
- double fpcrval;
- u_int64_t old;
+ union {
+ double d;
+ uint64_t u64;
+ } fpcrval;
- __asm("mf_fpcr %0" : "=f" (fpcrval));
- old = *(u_int64_t *)(void *)&fpcrval;
+ __asm("excb; mf_fpcr %0; excb" : "=f" (fpcrval.d));
- return ((old >> 58) & 0x3);
+ return ((fpcrval.u64 >> 58) & 0x3);
}
Index: src/lib/libc/arch/alpha/gen/fpsetround.c
diff -u src/lib/libc/arch/alpha/gen/fpsetround.c:1.10 src/lib/libc/arch/alpha/gen/fpsetround.c:1.11
--- src/lib/libc/arch/alpha/gen/fpsetround.c:1.10 Sat Dec 24 23:10:08 2005
+++ src/lib/libc/arch/alpha/gen/fpsetround.c Sun Jun 12 05:44:36 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: fpsetround.c,v 1.10 2005/12/24 23:10:08 perry Exp $ */
+/* $NetBSD: fpsetround.c,v 1.11 2011/06/12 05:44:36 matt Exp $ */
/*
* Copyright (c) 1995 Christopher G. Demetriou
@@ -36,7 +36,7 @@
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: fpsetround.c,v 1.10 2005/12/24 23:10:08 perry Exp $");
+__RCSID("$NetBSD: fpsetround.c,v 1.11 2011/06/12 05:44:36 matt Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
@@ -49,22 +49,22 @@
#endif
fp_rnd
-fpsetround(rnd_dir)
- fp_rnd rnd_dir;
+fpsetround(fp_rnd rnd_dir)
{
- double fpcrval;
- u_int64_t old, new;
+ union {
+ double d;
+ uint64_t u64;
+ } fpcrval;
+ fp_rnd old;
- __asm("excb");
- __asm("mf_fpcr %0" : "=f" (fpcrval));
- old = *(u_int64_t *)(void *)&fpcrval;
+ __asm("excb; mf_fpcr %0; excb" : "=f" (fpcrval.d));
+ old = (fpcrval.u64 >> 58) & 0x3;
- new = old & ~(long)0x0c00000000000000;
- new = (long)rnd_dir << 58;
- *(u_int64_t *)(void *)&fpcrval = new;
+ rnd_dir ^= old;
- __asm("mt_fpcr %0" : : "f" (fpcrval));
- __asm("excb");
+ fpcrval.u64 ^= (long)rnd_dir << 58;
- return ((old >> 58) & 0x3);
+ __asm("excb; mt_fpcr %0; excb" : : "f" (fpcrval.d));
+
+ return old;
}
