target/loongarch: Use normal float_status in fclass_s and fclass_d helpers

In target/loongarch's helper_fclass_s() and helper_fclass_d() we pass
a zero-initialized float_status struct to float32_is_quiet_nan() and
float64_is_quiet_nan(), with the cryptic comment "for
snan_bit_is_one".

This pattern appears to have been copied from target/riscv, where it
is used because the functions there do not have ready access to the
CPU state struct. The comment presumably refers to the fact that the
main reason the is_quiet_nan() functions want the float_state is
because they want to know about the snan_bit_is_one config.

In the loongarch helpers, though, we have the CPU state struct
to hand. Use the usual env->fp_status here. This avoids our needing
to track that we need to update the initializer of the local
float_status structs when the core softfloat code adds new
options for targets to configure their behaviour.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20241202131347.498124-30-peter.maydell@linaro.org

diff --git a/target/loongarch/tcg/fpu_helper.c b/target/loongarch/tcg/fpu_helper.c
index 37a48599366e0c0c7657b35bee0ee2b092e5345c..aea5e0fe5e62b9bb7070c035badea3cc1e0b4851 100644 (file)
--- a/target/loongarch/tcg/fpu_helper.c
+++ b/target/loongarch/tcg/fpu_helper.c
@@ -359,8 +359,7 @@ uint64_t helper_fclass_s(CPULoongArchState *env, uint64_t fj)
     } else if (float32_is_zero_or_denormal(f)) {
         return sign ? 1 << 4 : 1 << 8;
     } else if (float32_is_any_nan(f)) {
-        float_status s = { }; /* for snan_bit_is_one */
-        return float32_is_quiet_nan(f, &s) ? 1 << 1 : 1 << 0;
+        return float32_is_quiet_nan(f, &env->fp_status) ? 1 << 1 : 1 << 0;
     } else {
         return sign ? 1 << 3 : 1 << 7;
     }
@@ -378,8 +377,7 @@ uint64_t helper_fclass_d(CPULoongArchState *env, uint64_t fj)
     } else if (float64_is_zero_or_denormal(f)) {
         return sign ? 1 << 4 : 1 << 8;
     } else if (float64_is_any_nan(f)) {
-        float_status s = { }; /* for snan_bit_is_one */
-        return float64_is_quiet_nan(f, &s) ? 1 << 1 : 1 << 0;
+        return float64_is_quiet_nan(f, &env->fp_status) ? 1 << 1 : 1 << 0;
     } else {
         return sign ? 1 << 3 : 1 << 7;
     }