[src/trunk]: src/common/lib/libc Provide cas_16 and cas_8 emulation via cas_3...

[martin <martin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/83e80770eec8
branches:  trunk
changeset: 326976:83e80770eec8
user:      martin <martin%NetBSD.org@localhost>
date:      Mon Feb 24 16:15:43 2014 +0000

description:
Provide cas_16 and cas_8 emulation via cas_32 and use that for mips64

diffstat:

 common/lib/libc/arch/mips/atomic/Makefile.inc |   4 +-
 common/lib/libc/atomic/atomic_cas_by_cas32.c  |  77 +++++++++++++++++++++++++++
 2 files changed, 79 insertions(+), 2 deletions(-)

diffs (99 lines):

diff -r 8e635c3287ee -r 83e80770eec8 common/lib/libc/arch/mips/atomic/Makefile.inc
--- a/common/lib/libc/arch/mips/atomic/Makefile.inc     Mon Feb 24 15:47:43 2014 +0000
+++ b/common/lib/libc/arch/mips/atomic/Makefile.inc     Mon Feb 24 16:15:43 2014 +0000
@@ -1,4 +1,4 @@
-#      $NetBSD: Makefile.inc,v 1.11 2014/02/21 19:05:33 martin Exp $
+#      $NetBSD: Makefile.inc,v 1.12 2014/02/24 16:15:43 martin Exp $
 
 .if defined(LIB) && (${LIB} == "kern" || ${LIB} == "c" || ${LIB} == "pthread" \
        || ${LIB} == "rump")
@@ -33,7 +33,7 @@
 .if ${MACHINE_ARCH:Mmips64*} == ""
 SRCS+= atomic_init_testset.c atomic_cas_up.S
 .else
-SRCS+= atomic_cas.S atomic_init_cas.c
+SRCS+= atomic_cas.S atomic_init_cas.c atomic_cas_by_cas32.c
 .endif
 
 .endif
diff -r 8e635c3287ee -r 83e80770eec8 common/lib/libc/atomic/atomic_cas_by_cas32.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/common/lib/libc/atomic/atomic_cas_by_cas32.c      Mon Feb 24 16:15:43 2014 +0000
@@ -0,0 +1,77 @@
+/*     $NetBSD: atomic_cas_by_cas32.c,v 1.1 2014/02/24 16:15:43 martin Exp $   */
+
+/*-
+ * Copyright (c) 2014 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Jason R. Thorpe.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/inttypes.h>
+
+uint32_t _atomic_cas_32(volatile uint32_t *addr, uint32_t old, uint32_t new);
+uint16_t _atomic_cas_16(volatile uint16_t *addr, uint16_t old, uint16_t new);
+uint8_t _atomic_cas_8(volatile uint8_t *addr, uint8_t old, uint8_t new);
+
+/*
+ * This file provides emulation of 8 bit and 16 bit CAS operations based on
+ * 32 bit CAS.
+ */
+uint16_t
+_atomic_cas_16(volatile uint16_t *addr, uint16_t old, uint16_t new)
+{
+       const uintptr_t base = (uintptr_t)addr & ~3;
+       const size_t off = (uintptr_t)addr - base;
+       volatile uint32_t * ptr = (volatile uint32_t *)base;
+       const size_t shift = off*8;
+       const uint32_t mask = 0x0ffff << shift;
+       uint32_t old32, new32;
+
+       do {
+               old32 = *ptr;
+               new32 = (old32 & ~mask) | (uint32_t)new << shift;
+               old32 = (old32 & ~mask) | (uint32_t)old << shift;
+       } while (_atomic_cas_32(ptr, old32, new32) != old32);
+       return (old >> shift) & mask;
+}
+
+uint8_t
+_atomic_cas_8(volatile uint8_t *addr, uint8_t old, uint8_t new)
+{
+       const uintptr_t base = (uintptr_t)addr & ~3;
+       const size_t off = (uintptr_t)addr - base;
+       volatile uint32_t * ptr = (volatile uint32_t *)base;
+       const size_t shift = off*8;
+       const uint32_t mask = 0x0ff << shift;
+       uint32_t old32, new32;
+
+       do {
+               old32 = *ptr;
+               new32 = (old32 & ~mask) | (uint32_t)new << shift;
+               old32 = (old32 & ~mask) | (uint32_t)old << shift;
+       } while (_atomic_cas_32(ptr, old32, new32) != old32);
+       return (old >> shift) & mask;
+}