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authorWill Newton <will.newton@linaro.org>2014-01-31 14:47:35 +0000
committerPeter Maydell <peter.maydell@linaro.org>2014-01-31 14:47:35 +0000
commit43630e585300465b72ecf328822c8611724307de (patch)
treedcec72fd1e962c01ec659c148d7379cbb46ee5b6
parent2ce7062501c715aae0ad37c3923a3710dd8914df (diff)
downloadqemu-arm-43630e585300465b72ecf328822c8611724307de.tar.gz
target-arm: Add set_neon_rmode helper
This helper sets the rounding mode in the standard_fp_status word to allow NEON instructions to modify the rounding mode whilst using the standard FPSCR values for everything else. Signed-off-by: Will Newton <will.newton@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
-rw-r--r--target-arm/helper.c17
-rw-r--r--target-arm/helper.h1
2 files changed, 18 insertions, 0 deletions
diff --git a/target-arm/helper.c b/target-arm/helper.c
index b1541b9c40..ca5b0000ad 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -4048,6 +4048,23 @@ uint32_t HELPER(set_rmode)(uint32_t rmode, CPUARMState *env)
return prev_rmode;
}
+/* Set the current fp rounding mode in the standard fp status and return
+ * the old one. This is for NEON instructions that need to change the
+ * rounding mode but wish to use the standard FPSCR values for everything
+ * else. Always set the rounding mode back to the correct value after
+ * modifying it.
+ * The argument is a softfloat float_round_ value.
+ */
+uint32_t HELPER(set_neon_rmode)(uint32_t rmode, CPUARMState *env)
+{
+ float_status *fp_status = &env->vfp.standard_fp_status;
+
+ uint32_t prev_rmode = get_float_rounding_mode(fp_status);
+ set_float_rounding_mode(rmode, fp_status);
+
+ return prev_rmode;
+}
+
/* Half precision conversions. */
static float32 do_fcvt_f16_to_f32(uint32_t a, CPUARMState *env, float_status *s)
{
diff --git a/target-arm/helper.h b/target-arm/helper.h
index 70872dffc6..71b8411120 100644
--- a/target-arm/helper.h
+++ b/target-arm/helper.h
@@ -149,6 +149,7 @@ DEF_HELPER_3(vfp_ultod, f64, i64, i32, ptr)
DEF_HELPER_3(vfp_uqtod, f64, i64, i32, ptr)
DEF_HELPER_FLAGS_2(set_rmode, TCG_CALL_NO_RWG, i32, i32, env)
+DEF_HELPER_FLAGS_2(set_neon_rmode, TCG_CALL_NO_RWG, i32, i32, env)
DEF_HELPER_2(vfp_fcvt_f16_to_f32, f32, i32, env)
DEF_HELPER_2(vfp_fcvt_f32_to_f16, i32, f32, env)