From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: david@gibson.dropbear.id.au, qemu-ppc@nongnu.org
Subject: [Qemu-devel] [PATCH 3/7] target/ppc: Introduce fp number classification
Date: Thu, 11 Oct 2018 16:41:55 -0700 [thread overview]
Message-ID: <20181011234159.11496-4-richard.henderson@linaro.org> (raw)
In-Reply-To: <20181011234159.11496-1-richard.henderson@linaro.org>
Having a separate, logical classifiation of numbers will
unify more error paths for different formats.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
target/ppc/fpu_helper.c | 94 ++++++++++++++++++++++-------------------
1 file changed, 51 insertions(+), 43 deletions(-)
diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
index c9198f826d..9ae55b1e93 100644
--- a/target/ppc/fpu_helper.c
+++ b/target/ppc/fpu_helper.c
@@ -114,54 +114,62 @@ static inline int ppc_float64_get_unbiased_exp(float64 f)
return ((f >> 52) & 0x7FF) - 1023;
}
-#define COMPUTE_FPRF(tp) \
-void helper_compute_fprf_##tp(CPUPPCState *env, tp arg) \
+/* Classify a floating-point number. */
+enum {
+ is_normal = 1,
+ is_zero = 2,
+ is_denormal = 4,
+ is_inf = 8,
+ is_qnan = 16,
+ is_snan = 32,
+ is_neg = 64,
+};
+
+#define COMPUTE_CLASS(tp) \
+static int tp##_classify(tp arg) \
{ \
- int isneg; \
- int fprf; \
- \
- isneg = tp##_is_neg(arg); \
+ int ret = tp##_is_neg(arg) * is_neg; \
if (unlikely(tp##_is_any_nan(arg))) { \
- if (tp##_is_signaling_nan(arg, &env->fp_status)) { \
- /* Signaling NaN: flags are undefined */ \
- fprf = 0x00; \
- } else { \
- /* Quiet NaN */ \
- fprf = 0x11; \
- } \
+ float_status dummy = { }; /* snan_bit_is_one = 0 */ \
+ ret |= (tp##_is_signaling_nan(arg, &dummy) \
+ ? is_snan : is_qnan); \
} else if (unlikely(tp##_is_infinity(arg))) { \
- /* +/- infinity */ \
- if (isneg) { \
- fprf = 0x09; \
- } else { \
- fprf = 0x05; \
- } \
+ ret |= is_inf; \
+ } else if (tp##_is_zero(arg)) { \
+ ret |= is_zero; \
+ } else if (tp##_is_zero_or_denormal(arg)) { \
+ ret |= is_denormal; \
} else { \
- if (tp##_is_zero(arg)) { \
- /* +/- zero */ \
- if (isneg) { \
- fprf = 0x12; \
- } else { \
- fprf = 0x02; \
- } \
- } else { \
- if (tp##_is_zero_or_denormal(arg)) { \
- /* Denormalized numbers */ \
- fprf = 0x10; \
- } else { \
- /* Normalized numbers */ \
- fprf = 0x00; \
- } \
- if (isneg) { \
- fprf |= 0x08; \
- } else { \
- fprf |= 0x04; \
- } \
- } \
+ ret |= is_normal; \
} \
- /* We update FPSCR_FPRF */ \
- env->fpscr &= ~(0x1F << FPSCR_FPRF); \
- env->fpscr |= fprf << FPSCR_FPRF; \
+ return ret; \
+}
+
+COMPUTE_CLASS(float16)
+COMPUTE_CLASS(float32)
+COMPUTE_CLASS(float64)
+COMPUTE_CLASS(float128)
+
+static void set_fprf_from_class(CPUPPCState *env, int class)
+{
+ static const uint8_t fprf[6][2] = {
+ { 0x04, 0x08 }, /* normalized */
+ { 0x02, 0x12 }, /* zero */
+ { 0x14, 0x18 }, /* denormalized */
+ { 0x05, 0x09 }, /* infinity */
+ { 0x11, 0x11 }, /* qnan */
+ { 0x00, 0x00 }, /* snan -- flags are undefined */
+ };
+ bool isneg = class & is_neg;
+
+ env->fpscr &= ~(0x1F << FPSCR_FPRF);
+ env->fpscr |= fprf[ctz32(class)][isneg] << FPSCR_FPRF;
+}
+
+#define COMPUTE_FPRF(tp) \
+void helper_compute_fprf_##tp(CPUPPCState *env, tp arg) \
+{ \
+ set_fprf_from_class(env, tp##_classify(arg)); \
}
COMPUTE_FPRF(float16)
--
2.17.1
next prev parent reply other threads:[~2018-10-11 23:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-11 23:41 [Qemu-devel] [PATCH 0/7] target/ppc: Some cleanups to fp exceptions Richard Henderson
2018-10-11 23:41 ` [Qemu-devel] [PATCH 1/7] target/ppc: Split up float_invalid_op_excp Richard Henderson
2018-10-11 23:41 ` [Qemu-devel] [PATCH 2/7] target/ppc: Remove float_check_status Richard Henderson
2018-10-11 23:41 ` Richard Henderson [this message]
2018-10-11 23:41 ` [Qemu-devel] [PATCH 4/7] target/ppc: Split out float_invalid_op_addsub Richard Henderson
2018-10-11 23:41 ` [Qemu-devel] [PATCH 5/7] target/ppc: Split out float_invalid_op_mul Richard Henderson
2018-10-11 23:41 ` [Qemu-devel] [PATCH 6/7] target/ppc: Split out float_invalid_op_div Richard Henderson
2018-10-11 23:41 ` [Qemu-devel] [PATCH 7/7] target/ppc: Split out float_invalid_cvt Richard Henderson
2018-10-12 1:14 ` [Qemu-devel] [PATCH 0/7] target/ppc: Some cleanups to fp exceptions David Gibson
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