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[Qemu-devel] [PATCH v5] target-sparc: Add and use CPU_FEATURE_CASA
From: |
Sebastian Huber |
Subject: |
[Qemu-devel] [PATCH v5] target-sparc: Add and use CPU_FEATURE_CASA |
Date: |
Sun, 09 Mar 2014 12:02:27 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 |
The LEON3 processor has support for the CASA instruction which is
normally only available for SPARC V9 processors. Binutils 2.24
and GCC 4.9 will support this instruction for LEON3. GCC uses it to
generate C11 atomic operations.
The CAS synthetic instruction uses an ASI of 0x80. If TARGET_SPARC64 is
not defined use a supervisor data load/store for an ASI of 0x80 in
helper_ld_asi()/helper_st_asi(). The supervisor data load/store was
choosen according to the LEON3 documentation.
The ASI 0x80 is defined in the SPARC V9 manual, Table 12—Address Space
Identifiers (ASIs). Here we have: 0x80, ASI_PRIMARY, Unrestricted
access, Primary address space.
Tested with the following program:
#include <assert.h>
#include <stdatomic.h>
void test(void)
{
atomic_int a;
int e;
_Bool b;
atomic_store(&a, 1);
e = 1;
b = atomic_compare_exchange_strong(&a, &e, 2);
assert(b);
assert(atomic_load(&a) == 2);
atomic_store(&a, 3);
e = 4;
b = atomic_compare_exchange_strong(&a, &e, 5);
assert(!b);
assert(atomic_load(&a) == 3);
}
Tested also on a NGMP board with a LEON4 processor.
Reviewed-by: Fabien Chouteau <address@hidden>
Reviewed-by: Andreas Färber <address@hidden>
Signed-off-by: Sebastian Huber <address@hidden>
v4: Fix coding style.
v5: Fix two typos. Generate an IU instead of FPU exception in case CASA
is not supported by the CPU. Define CASA feature for all SPARC64 CPUs
(due to the #ifndef TARGET_SPARC64 it must go into the #else branch).
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail : address@hidden
PGP : Public key available on request.
Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
0001-target-sparc-Add-and-use-CPU_FEATURE_CASA.patch
Description: Text Data
- [Qemu-devel] [PATCH v5] target-sparc: Add and use CPU_FEATURE_CASA,
Sebastian Huber <=