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[Qemu-devel] [PATCH 5/5] tcg-arm: Use AT_PLATFORM to detect the host ISA
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 5/5] tcg-arm: Use AT_PLATFORM to detect the host ISA |
Date: |
Thu, 6 Jun 2013 11:05:47 -0700 |
With this we can generate armv7 insns even when the OS compiles for a
lower common denominator. The macros are arranged so that when we do
compile for a given ISA, all of the runtime checks for that ISA are
optimized away.
Signed-off-by: Richard Henderson <address@hidden>
---
tcg/arm/tcg-target.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/tcg/arm/tcg-target.c b/tcg/arm/tcg-target.c
index 202f1fc..243dedd 100644
--- a/tcg/arm/tcg-target.c
+++ b/tcg/arm/tcg-target.c
@@ -41,9 +41,11 @@
# endif
#endif
-#define use_armv5_instructions (__ARM_ARCH >= 5)
-#define use_armv6_instructions (__ARM_ARCH >= 6)
-#define use_armv7_instructions (__ARM_ARCH >= 7)
+static int arm_arch = __ARM_ARCH;
+
+#define use_armv5_instructions (__ARM_ARCH >= 5 || arm_arch >= 5)
+#define use_armv6_instructions (__ARM_ARCH >= 6 || arm_arch >= 6)
+#define use_armv7_instructions (__ARM_ARCH >= 7 || arm_arch >= 7)
#ifndef use_idiv_instructions
bool use_idiv_instructions;
@@ -2036,12 +2038,22 @@ static const TCGTargetOpDef arm_op_defs[] = {
static void tcg_target_init(TCGContext *s)
{
-#if defined(CONFIG_GETAUXVAL) && !defined(use_idiv_instructions)
+#if defined(CONFIG_GETAUXVAL)
+ /* Only probe for the platform and capabilities if we havn't already
+ determined maximum values at compile time. */
+# if !defined(use_idiv_instructions)
{
unsigned long hwcap = getauxval(AT_HWCAP);
use_idiv_instructions = hwcap & (HWCAP_ARM_IDIVA | HWCAP_ARM_IDIVT);
}
-#endif
+# endif
+ if (__ARM_ARCH < 7) {
+ const char *pl = (const char *)getauxval(AT_PLATFORM);
+ if (pl != NULL && pl[0] == 'v' && pl[1] >= '4' && pl[1] <= '9') {
+ arm_arch = pl[1] - '0';
+ }
+ }
+#endif /* GETAUXVAL */
#if !defined(CONFIG_USER_ONLY)
/* fail safe */
--
1.8.1.4
- [Qemu-devel] [PATCH 0/5] tcg-arm: Runtime detection of architecture, Richard Henderson, 2013/06/06
- [Qemu-devel] [PATCH 1/5] tcg: Allow non-constant control macros, Richard Henderson, 2013/06/06
- [Qemu-devel] [PATCH 2/5] tcg: Simplify logic using TCG_OPF_NOT_PRESENT, Richard Henderson, 2013/06/06
- [Qemu-devel] [PATCH 4/5] tcg-arm: Simplify logic in detecting the ARM ISA in use, Richard Henderson, 2013/06/06
- [Qemu-devel] [PATCH 3/5] tcg-arm: Make use of conditional availability of opcodes for divide, Richard Henderson, 2013/06/06
- [Qemu-devel] [PATCH 5/5] tcg-arm: Use AT_PLATFORM to detect the host ISA,
Richard Henderson <=
- Re: [Qemu-devel] [PATCH 0/5] tcg-arm: Runtime detection of architecture, Richard Henderson, 2013/06/10