fpu: Rename float_flag_input_denormal to float_flag_input_denormal_flushed

Our float_flag_input_denormal exception flag is set when the fpu code
flushes an input denormal to zero.  This is what many guest
architectures (eg classic Arm behaviour) require, but it is not the
only donarmal-related reason we might want to set an exception flag.
The x86 behaviour (which we do not currently model correctly) wants
to see an exception flag when a denormal input is *not* flushed to
zero and is actually used in an arithmetic operation. Arm's FEAT_AFP
also wants these semantics.

Rename float_flag_input_denormal to float_flag_input_denormal_flushed
to make it clearer when it is set and to allow us to add a new
float_flag_input_denormal_used next to it for the x86/FEAT_AFP
semantics.

Commit created with
 for f in `git grep -l float_flag_input_denormal`; do sed -i -e 's/float_flag_input_denormal/float_flag_input_denormal_flushed/' $f; done

and manual editing of softfloat-types.h and softfloat.c to clean
up the indentation afterwards and to fix a comment which wasn't
using the full name of the flag.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250124162836.2332150-20-peter.maydell@linaro.org

diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index ebde42992fcb7f55d20beeaec118efe453b91cc3..b3d693eed0ee227fd607f42eb4938680474d743b 100644 (file)
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -198,7 +198,7 @@ static void partsN(canonicalize)(FloatPartsN *p, float_status *status,
         if (likely(frac_eqz(p))) {
             p->cls = float_class_zero;
         } else if (status->flush_inputs_to_zero) {
-            float_raise(float_flag_input_denormal, status);
+            float_raise(float_flag_input_denormal_flushed, status);
             p->cls = float_class_zero;
             frac_clear(p);
         } else {

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 8d75d668172bf482914ddad74b4c7754bf16ee9b..648050be6fbe75cf7f012b90a86baebc551bafa5 100644 (file)
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -132,7 +132,7 @@ this code that are retained.
         if (unlikely(soft_t ## _is_denormal(*a))) {                     \
             *a = soft_t ## _set_sign(soft_t ## _zero,                   \
                                      soft_t ## _is_neg(*a));            \
-            float_raise(float_flag_input_denormal, s);                  \
+            float_raise(float_flag_input_denormal_flushed, s);          \
         }                                                               \
     }
 
@@ -4848,7 +4848,7 @@ float128 float128_silence_nan(float128 a, float_status *status)
 static bool parts_squash_denormal(FloatParts64 p, float_status *status)
 {
     if (p.exp == 0 && p.frac != 0) {
-        float_raise(float_flag_input_denormal, status);
+        float_raise(float_flag_input_denormal_flushed, status);
         return true;
     }
 

diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h
index 9d37cdfaa8e3dcd762b2e1dc2d64913a33c15aa2..24cd290a1df9888531439d723ad40e8e21f1508c 100644 (file)
--- a/include/fpu/softfloat-types.h
+++ b/include/fpu/softfloat-types.h
@@ -154,7 +154,8 @@ enum {
     float_flag_overflow        = 0x0004,
     float_flag_underflow       = 0x0008,
     float_flag_inexact         = 0x0010,
-    float_flag_input_denormal  = 0x0020,
+    /* We flushed an input denormal to 0 (because of flush_inputs_to_zero) */
+    float_flag_input_denormal_flushed = 0x0020,
     float_flag_output_denormal = 0x0040,
     float_flag_invalid_isi     = 0x0080,  /* inf - inf */
     float_flag_invalid_imz     = 0x0100,  /* inf * 0 */
@@ -302,7 +303,7 @@ typedef struct float_status {
     bool tininess_before_rounding;
     /* should denormalised results go to zero and set the inexact flag? */
     bool flush_to_zero;
-    /* should denormalised inputs go to zero and set the input_denormal flag? */
+    /* should denormalised inputs go to zero and set input_denormal_flushed? */
     bool flush_inputs_to_zero;
     bool default_nan_mode;
     /*

diff --git a/target/arm/tcg/sve_helper.c b/target/arm/tcg/sve_helper.c
index d0865dece35d246ec89c9383a57d2bd81108777c..9837c5bc7ac6e01faf6e86099258a7248aed947e 100644 (file)
--- a/target/arm/tcg/sve_helper.c
+++ b/target/arm/tcg/sve_helper.c
@@ -4658,7 +4658,7 @@ static int16_t do_float16_logb_as_int(float16 a, float_status *s)
                 return -15 - clz32(frac);
             }
             /* flush to zero */
-            float_raise(float_flag_input_denormal, s);
+            float_raise(float_flag_input_denormal_flushed, s);
         }
     } else if (unlikely(exp == 0x1f)) {
         if (frac == 0) {
@@ -4686,7 +4686,7 @@ static int32_t do_float32_logb_as_int(float32 a, float_status *s)
                 return -127 - clz32(frac);
             }
             /* flush to zero */
-            float_raise(float_flag_input_denormal, s);
+            float_raise(float_flag_input_denormal_flushed, s);
         }
     } else if (unlikely(exp == 0xff)) {
         if (frac == 0) {
@@ -4714,7 +4714,7 @@ static int64_t do_float64_logb_as_int(float64 a, float_status *s)
                 return -1023 - clz64(frac);
             }
             /* flush to zero */
-            float_raise(float_flag_input_denormal, s);
+            float_raise(float_flag_input_denormal_flushed, s);
         }
     } else if (unlikely(exp == 0x7ff)) {
         if (frac == 0) {

diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index 3ed69d736984789f20cb54134fe113dd5a38016a..444702a46007268e30668326a4291c9a61532216 100644 (file)
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -53,7 +53,7 @@ static inline uint32_t vfp_exceptbits_from_host(int host_bits)
     if (host_bits & float_flag_inexact) {
         target_bits |= FPSR_IXC;
     }
-    if (host_bits & float_flag_input_denormal) {
+    if (host_bits & float_flag_input_denormal_flushed) {
         target_bits |= FPSR_IDC;
     }
     return target_bits;
@@ -68,11 +68,11 @@ static uint32_t vfp_get_fpsr_from_host(CPUARMState *env)
     i |= get_float_exception_flags(&env->vfp.standard_fp_status);
     /* FZ16 does not generate an input denormal exception.  */
     i |= (get_float_exception_flags(&env->vfp.fp_status_f16_a32)
-          & ~float_flag_input_denormal);
+          & ~float_flag_input_denormal_flushed);
     i |= (get_float_exception_flags(&env->vfp.fp_status_f16_a64)
-          & ~float_flag_input_denormal);
+          & ~float_flag_input_denormal_flushed);
     i |= (get_float_exception_flags(&env->vfp.standard_fp_status_f16)
-          & ~float_flag_input_denormal);
+          & ~float_flag_input_denormal_flushed);
     return vfp_exceptbits_from_host(i);
 }
 
@@ -1133,7 +1133,7 @@ uint64_t HELPER(fjcvtzs)(float64 value, float_status *status)
 
     /* Normal inexact, denormal with flush-to-zero, or overflow or NaN */
     inexact = e_new & (float_flag_inexact |
-                       float_flag_input_denormal |
+                       float_flag_input_denormal_flushed |
                        float_flag_invalid);
 
     /* While not inexact for IEEE FP, -0.0 is inexact for JavaScript. */

diff --git a/target/i386/tcg/fpu_helper.c b/target/i386/tcg/fpu_helper.c
index d0a1e2f3c8a0353a77feef0bc0cbbad8cf67f672..9c33ac7898bbfde8918c3f9679b42e08f6b69705 100644 (file)
--- a/target/i386/tcg/fpu_helper.c
+++ b/target/i386/tcg/fpu_helper.c
@@ -204,7 +204,7 @@ static void merge_exception_flags(CPUX86State *env, uint8_t old_flags)
                        (new_flags & float_flag_overflow ? FPUS_OE : 0) |
                        (new_flags & float_flag_underflow ? FPUS_UE : 0) |
                        (new_flags & float_flag_inexact ? FPUS_PE : 0) |
-                       (new_flags & float_flag_input_denormal ? FPUS_DE : 0)));
+                       (new_flags & float_flag_input_denormal_flushed ? FPUS_DE : 0)));
 }
 
 static inline floatx80 helper_fdiv(CPUX86State *env, floatx80 a, floatx80 b)
@@ -1829,7 +1829,7 @@ void helper_fxtract(CPUX86State *env)
             int shift = clz64(temp.l.lower);
             temp.l.lower <<= shift;
             expdif = 1 - EXPBIAS - shift;
-            float_raise(float_flag_input_denormal, &env->fp_status);
+            float_raise(float_flag_input_denormal_flushed, &env->fp_status);
         } else {
             expdif = EXPD(temp) - EXPBIAS;
         }
@@ -3258,7 +3258,7 @@ void update_mxcsr_from_sse_status(CPUX86State *env)
     uint8_t flags = get_float_exception_flags(&env->sse_status);
     /*
      * The MXCSR denormal flag has opposite semantics to
-     * float_flag_input_denormal (the softfloat code sets that flag
+     * float_flag_input_denormal_flushed (the softfloat code sets that flag
      * only when flushing input denormals to zero, but SSE sets it
      * only when not flushing them to zero), so is not converted
      * here.

diff --git a/target/mips/tcg/msa_helper.c b/target/mips/tcg/msa_helper.c
index 1d40383ca4ff9dadbfe02b2aaeda6ee2921919ea..aeab6a1d8b3cc0cc9b1cb8498940e0d7a6b8663a 100644 (file)
--- a/target/mips/tcg/msa_helper.c
+++ b/target/mips/tcg/msa_helper.c
@@ -6231,7 +6231,7 @@ static inline int update_msacsr(CPUMIPSState *env, int action, int denormal)
     enable = GET_FP_ENABLE(env->active_tc.msacsr) | FP_UNIMPLEMENTED;
 
     /* Set Inexact (I) when flushing inputs to zero */
-    if ((ieee_exception_flags & float_flag_input_denormal) &&
+    if ((ieee_exception_flags & float_flag_input_denormal_flushed) &&
             (env->active_tc.msacsr & MSACSR_FS_MASK) != 0) {
         if (action & CLEAR_IS_INEXACT) {
             mips_exception_flags &= ~FP_INEXACT;

diff --git a/target/rx/op_helper.c b/target/rx/op_helper.c
index 691a12b2be1b6aa426baeed2dbe05af2ee10df00..59dd1ae61284b548d85f383fdb2d424da5bb09e0 100644 (file)
--- a/target/rx/op_helper.c
+++ b/target/rx/op_helper.c
@@ -99,7 +99,7 @@ static void update_fpsw(CPURXState *env, float32 ret, uintptr_t retaddr)
         if (xcpt & float_flag_inexact) {
             SET_FPSW(X);
         }
-        if ((xcpt & (float_flag_input_denormal
+        if ((xcpt & (float_flag_input_denormal_flushed
                      | float_flag_output_denormal))
             && !FIELD_EX32(env->fpsw, FPSW, DN)) {
             env->fpsw = FIELD_DP32(env->fpsw, FPSW, CE, 1);