[Qemu-devel] [PATCH] target-arm/helper.c: For float-int conversion helpers pass ints as ints

[Qemu-devel] [PATCH] target-arm/helper.c: For float-int conversion helpers pass ints as ints

[Peter Maydell]

Correct the argument and return types for the float<->int conversion helper
functions so that integer arguments and return values are declared as
uint32_t/uint64_t, not float32/float64. This allows us to remove the
hand-rolled functions which were doing bitwise copies between the types
via unions.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
This patch is in some ways doing for helper.c what the patch
http://patchwork.ozlabs.org/patch/86441/ did for neon_helper.c,
although in this case I opted to fix the prototypes not to pass
integer arguments in and out in float32/float64 rather than simply
replacing the helper functions with make_float*/float*_val calls.

There should be no behaviour change here, it's just a code cleanup.
Tested with the usual random-instruction-set stuff.

 target-arm/helper.c  |  155 ++++++++++++++++++--------------------------------
 target-arm/helpers.h |   60 ++++++++++----------
 2 files changed, 85 insertions(+), 130 deletions(-)

diff --git a/target-arm/helper.c b/target-arm/helper.c
index d360121..ff9f59b 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -2486,135 +2486,90 @@ DO_VFP_cmp(s, float32)
 DO_VFP_cmp(d, float64)
 #undef DO_VFP_cmp
 
-/* Helper routines to perform bitwise copies between float and int.  */
-static inline float32 vfp_itos(uint32_t i)
-{
-    union {
-        uint32_t i;
-        float32 s;
-    } v;
-
-    v.i = i;
-    return v.s;
-}
-
-static inline uint32_t vfp_stoi(float32 s)
-{
-    union {
-        uint32_t i;
-        float32 s;
-    } v;
-
-    v.s = s;
-    return v.i;
-}
-
-static inline float64 vfp_itod(uint64_t i)
-{
-    union {
-        uint64_t i;
-        float64 d;
-    } v;
-
-    v.i = i;
-    return v.d;
-}
-
-static inline uint64_t vfp_dtoi(float64 d)
-{
-    union {
-        uint64_t i;
-        float64 d;
-    } v;
-
-    v.d = d;
-    return v.i;
-}
-
 /* Integer to float conversion.  */
-float32 VFP_HELPER(uito, s)(float32 x, CPUState *env)
+float32 VFP_HELPER(uito, s)(uint32_t x, CPUState *env)
 {
-    return uint32_to_float32(vfp_stoi(x), &env->vfp.fp_status);
+    return uint32_to_float32(x, &env->vfp.fp_status);
 }
 
-float64 VFP_HELPER(uito, d)(float32 x, CPUState *env)
+float64 VFP_HELPER(uito, d)(uint32_t x, CPUState *env)
 {
-    return uint32_to_float64(vfp_stoi(x), &env->vfp.fp_status);
+    return uint32_to_float64(x, &env->vfp.fp_status);
 }
 
-float32 VFP_HELPER(sito, s)(float32 x, CPUState *env)
+float32 VFP_HELPER(sito, s)(uint32_t x, CPUState *env)
 {
-    return int32_to_float32(vfp_stoi(x), &env->vfp.fp_status);
+    return int32_to_float32(x, &env->vfp.fp_status);
 }
 
-float64 VFP_HELPER(sito, d)(float32 x, CPUState *env)
+float64 VFP_HELPER(sito, d)(uint32_t x, CPUState *env)
 {
-    return int32_to_float64(vfp_stoi(x), &env->vfp.fp_status);
+    return int32_to_float64(x, &env->vfp.fp_status);
 }
 
 /* Float to integer conversion.  */
-float32 VFP_HELPER(toui, s)(float32 x, CPUState *env)
+uint32_t VFP_HELPER(toui, s)(float32 x, CPUState *env)
 {
     if (float32_is_any_nan(x)) {
-        return float32_zero;
+        return 0;
     }
-    return vfp_itos(float32_to_uint32(x, &env->vfp.fp_status));
+    return float32_to_uint32(x, &env->vfp.fp_status);
 }
 
-float32 VFP_HELPER(toui, d)(float64 x, CPUState *env)
+uint32_t VFP_HELPER(toui, d)(float64 x, CPUState *env)
 {
     if (float64_is_any_nan(x)) {
-        return float32_zero;
+        return 0;
     }
-    return vfp_itos(float64_to_uint32(x, &env->vfp.fp_status));
+    return float64_to_uint32(x, &env->vfp.fp_status);
 }
 
-float32 VFP_HELPER(tosi, s)(float32 x, CPUState *env)
+uint32_t VFP_HELPER(tosi, s)(float32 x, CPUState *env)
 {
     if (float32_is_any_nan(x)) {
-        return float32_zero;
+        return 0;
     }
-    return vfp_itos(float32_to_int32(x, &env->vfp.fp_status));
+    return float32_to_int32(x, &env->vfp.fp_status);
 }
 
-float32 VFP_HELPER(tosi, d)(float64 x, CPUState *env)
+uint32_t VFP_HELPER(tosi, d)(float64 x, CPUState *env)
 {
     if (float64_is_any_nan(x)) {
-        return float32_zero;
+        return 0;
     }
-    return vfp_itos(float64_to_int32(x, &env->vfp.fp_status));
+    return float64_to_int32(x, &env->vfp.fp_status);
 }
 
-float32 VFP_HELPER(touiz, s)(float32 x, CPUState *env)
+uint32_t VFP_HELPER(touiz, s)(float32 x, CPUState *env)
 {
     if (float32_is_any_nan(x)) {
-        return float32_zero;
+        return 0;
     }
-    return vfp_itos(float32_to_uint32_round_to_zero(x, &env->vfp.fp_status));
+    return float32_to_uint32_round_to_zero(x, &env->vfp.fp_status);
 }
 
-float32 VFP_HELPER(touiz, d)(float64 x, CPUState *env)
+uint32_t VFP_HELPER(touiz, d)(float64 x, CPUState *env)
 {
     if (float64_is_any_nan(x)) {
-        return float32_zero;
+        return 0;
     }
-    return vfp_itos(float64_to_uint32_round_to_zero(x, &env->vfp.fp_status));
+    return float64_to_uint32_round_to_zero(x, &env->vfp.fp_status);
 }
 
-float32 VFP_HELPER(tosiz, s)(float32 x, CPUState *env)
+uint32_t VFP_HELPER(tosiz, s)(float32 x, CPUState *env)
 {
     if (float32_is_any_nan(x)) {
-        return float32_zero;
+        return 0;
     }
-    return vfp_itos(float32_to_int32_round_to_zero(x, &env->vfp.fp_status));
+    return float32_to_int32_round_to_zero(x, &env->vfp.fp_status);
 }
 
-float32 VFP_HELPER(tosiz, d)(float64 x, CPUState *env)
+uint32_t VFP_HELPER(tosiz, d)(float64 x, CPUState *env)
 {
     if (float64_is_any_nan(x)) {
-        return float32_zero;
+        return 0;
     }
-    return vfp_itos(float64_to_int32_round_to_zero(x, &env->vfp.fp_status));
+    return float64_to_int32_round_to_zero(x, &env->vfp.fp_status);
 }
 
 /* floating point conversion */
@@ -2637,33 +2592,33 @@ float32 VFP_HELPER(fcvts, d)(float64 x, CPUState *env)
 }
 
 /* VFP3 fixed point conversion.  */
-#define VFP_CONV_FIX(name, p, ftype, itype, sign) \
-ftype VFP_HELPER(name##to, p)(ftype x, uint32_t shift, CPUState *env) \
+#define VFP_CONV_FIX(name, p, fsz, itype, sign) \
+float##fsz VFP_HELPER(name##to, p)(uint##fsz##_t  x, uint32_t shift, \
+                                   CPUState *env) \
 { \
-    ftype tmp; \
-    tmp = sign##int32_to_##ftype ((itype##_t)vfp_##p##toi(x), \
-                                  &env->vfp.fp_status); \
-    return ftype##_scalbn(tmp, -(int)shift, &env->vfp.fp_status); \
+    float##fsz tmp; \
+    tmp = sign##int32_to_##float##fsz ((itype##_t)x, &env->vfp.fp_status); \
+    return float##fsz##_scalbn(tmp, -(int)shift, &env->vfp.fp_status); \
 } \
-ftype VFP_HELPER(to##name, p)(ftype x, uint32_t shift, CPUState *env) \
+uint##fsz##_t VFP_HELPER(to##name, p)(float##fsz x, uint32_t shift, \
+                                      CPUState *env) \
 { \
-    ftype tmp; \
-    if (ftype##_is_any_nan(x)) { \
-        return ftype##_zero; \
+    float##fsz tmp; \
+    if (float##fsz##_is_any_nan(x)) { \
+        return 0; \
     } \
-    tmp = ftype##_scalbn(x, shift, &env->vfp.fp_status); \
-    return vfp_ito##p(ftype##_to_##itype##_round_to_zero(tmp, \
-        &env->vfp.fp_status)); \
-}
-
-VFP_CONV_FIX(sh, d, float64, int16, )
-VFP_CONV_FIX(sl, d, float64, int32, )
-VFP_CONV_FIX(uh, d, float64, uint16, u)
-VFP_CONV_FIX(ul, d, float64, uint32, u)
-VFP_CONV_FIX(sh, s, float32, int16, )
-VFP_CONV_FIX(sl, s, float32, int32, )
-VFP_CONV_FIX(uh, s, float32, uint16, u)
-VFP_CONV_FIX(ul, s, float32, uint32, u)
+    tmp = float##fsz##_scalbn(x, shift, &env->vfp.fp_status); \
+    return float##fsz##_to_##itype##_round_to_zero(tmp, &env->vfp.fp_status); \
+}
+
+VFP_CONV_FIX(sh, d, 64, int16, )
+VFP_CONV_FIX(sl, d, 64, int32, )
+VFP_CONV_FIX(uh, d, 64, uint16, u)
+VFP_CONV_FIX(ul, d, 64, uint32, u)
+VFP_CONV_FIX(sh, s, 32, int16, )
+VFP_CONV_FIX(sl, s, 32, int32, )
+VFP_CONV_FIX(uh, s, 32, uint16, u)
+VFP_CONV_FIX(ul, s, 32, uint32, u)
 #undef VFP_CONV_FIX
 
 /* Half precision conversions.  */
diff --git a/target-arm/helpers.h b/target-arm/helpers.h
index bd6977c..9de10e3 100644
--- a/target-arm/helpers.h
+++ b/target-arm/helpers.h
@@ -96,36 +96,36 @@ DEF_HELPER_3(vfp_cmped, void, f64, f64, env)
 DEF_HELPER_2(vfp_fcvtds, f64, f32, env)
 DEF_HELPER_2(vfp_fcvtsd, f32, f64, env)
 
-DEF_HELPER_2(vfp_uitos, f32, f32, env)
-DEF_HELPER_2(vfp_uitod, f64, f32, env)
-DEF_HELPER_2(vfp_sitos, f32, f32, env)
-DEF_HELPER_2(vfp_sitod, f64, f32, env)
-
-DEF_HELPER_2(vfp_touis, f32, f32, env)
-DEF_HELPER_2(vfp_touid, f32, f64, env)
-DEF_HELPER_2(vfp_touizs, f32, f32, env)
-DEF_HELPER_2(vfp_touizd, f32, f64, env)
-DEF_HELPER_2(vfp_tosis, f32, f32, env)
-DEF_HELPER_2(vfp_tosid, f32, f64, env)
-DEF_HELPER_2(vfp_tosizs, f32, f32, env)
-DEF_HELPER_2(vfp_tosizd, f32, f64, env)
-
-DEF_HELPER_3(vfp_toshs, f32, f32, i32, env)
-DEF_HELPER_3(vfp_tosls, f32, f32, i32, env)
-DEF_HELPER_3(vfp_touhs, f32, f32, i32, env)
-DEF_HELPER_3(vfp_touls, f32, f32, i32, env)
-DEF_HELPER_3(vfp_toshd, f64, f64, i32, env)
-DEF_HELPER_3(vfp_tosld, f64, f64, i32, env)
-DEF_HELPER_3(vfp_touhd, f64, f64, i32, env)
-DEF_HELPER_3(vfp_tould, f64, f64, i32, env)
-DEF_HELPER_3(vfp_shtos, f32, f32, i32, env)
-DEF_HELPER_3(vfp_sltos, f32, f32, i32, env)
-DEF_HELPER_3(vfp_uhtos, f32, f32, i32, env)
-DEF_HELPER_3(vfp_ultos, f32, f32, i32, env)
-DEF_HELPER_3(vfp_shtod, f64, f64, i32, env)
-DEF_HELPER_3(vfp_sltod, f64, f64, i32, env)
-DEF_HELPER_3(vfp_uhtod, f64, f64, i32, env)
-DEF_HELPER_3(vfp_ultod, f64, f64, i32, env)
+DEF_HELPER_2(vfp_uitos, f32, i32, env)
+DEF_HELPER_2(vfp_uitod, f64, i32, env)
+DEF_HELPER_2(vfp_sitos, f32, i32, env)
+DEF_HELPER_2(vfp_sitod, f64, i32, env)
+
+DEF_HELPER_2(vfp_touis, i32, f32, env)
+DEF_HELPER_2(vfp_touid, i32, f64, env)
+DEF_HELPER_2(vfp_touizs, i32, f32, env)
+DEF_HELPER_2(vfp_touizd, i32, f64, env)
+DEF_HELPER_2(vfp_tosis, i32, f32, env)
+DEF_HELPER_2(vfp_tosid, i32, f64, env)
+DEF_HELPER_2(vfp_tosizs, i32, f32, env)
+DEF_HELPER_2(vfp_tosizd, i32, f64, env)
+
+DEF_HELPER_3(vfp_toshs, i32, f32, i32, env)
+DEF_HELPER_3(vfp_tosls, i32, f32, i32, env)
+DEF_HELPER_3(vfp_touhs, i32, f32, i32, env)
+DEF_HELPER_3(vfp_touls, i32, f32, i32, env)
+DEF_HELPER_3(vfp_toshd, i64, f64, i32, env)
+DEF_HELPER_3(vfp_tosld, i64, f64, i32, env)
+DEF_HELPER_3(vfp_touhd, i64, f64, i32, env)
+DEF_HELPER_3(vfp_tould, i64, f64, i32, env)
+DEF_HELPER_3(vfp_shtos, f32, i32, i32, env)
+DEF_HELPER_3(vfp_sltos, f32, i32, i32, env)
+DEF_HELPER_3(vfp_uhtos, f32, i32, i32, env)
+DEF_HELPER_3(vfp_ultos, f32, i32, i32, env)
+DEF_HELPER_3(vfp_shtod, f64, i64, i32, env)
+DEF_HELPER_3(vfp_sltod, f64, i64, i32, env)
+DEF_HELPER_3(vfp_uhtod, f64, i64, i32, env)
+DEF_HELPER_3(vfp_ultod, f64, i64, i32, env)
 
 DEF_HELPER_2(vfp_fcvt_f16_to_f32, f32, i32, env)
 DEF_HELPER_2(vfp_fcvt_f32_to_f16, i32, f32, env)
-- 
1.7.1

Re: [Qemu-devel] [PATCH] target-arm/helper.c: For float-int conversion helpers pass ints as ints

[Nathan Froyd]

On Mon, Mar 14, 2011 at 05:23:11PM +0000, Peter Maydell wrote:
> Correct the argument and return types for the float<->int conversion helper
> functions so that integer arguments and return values are declared as
> uint32_t/uint64_t, not float32/float64. This allows us to remove the
> hand-rolled functions which were doing bitwise copies between the types
> via unions.

Reviewed-by: Nathan Froyd <froydnj@codesourcery.com>

I like the direction this patch goes; you aren't by any chance going to
convert the passing/returning of float* to their appropriate int* types
too, are you?

-Nathan

Re: [Qemu-devel] [PATCH] target-arm/helper.c: For float-int conversion helpers pass ints as ints

[Peter Maydell]

On 21 March 2011 13:48, Nathan Froyd <froydnj@codesourcery.com> wrote:
> On Mon, Mar 14, 2011 at 05:23:11PM +0000, Peter Maydell wrote:
>> Correct the argument and return types for the float<->int conversion helper
>> functions so that integer arguments and return values are declared as
>> uint32_t/uint64_t, not float32/float64.

> I like the direction this patch goes; you aren't by any chance going to
> convert the passing/returning of float* to their appropriate int* types
> too, are you?

Nope -- I think that where we're passing or returning an actual
IEEE single/double to a helper function "float*" is a better type
than uint32_t: it gives information about what the helper's argument
semantically is, and it means we don't have every helper that takes
or returns a float have to include ugly calls to the boxing/unboxing
macros.

-- PMM

Re: [Qemu-devel] [PATCH] target-arm/helper.c: For float-int conversion helpers pass ints as ints

[Nathan Froyd]

On Mon, Mar 21, 2011 at 02:04:31PM +0000, Peter Maydell wrote:
> On 21 March 2011 13:48, Nathan Froyd <froydnj@codesourcery.com> wrote:
> > I like the direction this patch goes; you aren't by any chance going to
> > convert the passing/returning of float* to their appropriate int* types
> > too, are you?
> 
> Nope -- I think that where we're passing or returning an actual
> IEEE single/double to a helper function "float*" is a better type
> than uint32_t: it gives information about what the helper's argument
> semantically is, and it means we don't have every helper that takes
> or returns a float have to include ugly calls to the boxing/unboxing
> macros.

I'm just concerned about what would happen if we turned on softfloat's
"float types are structure types" bit; I'm pretty sure everything would
break horribly on targets that don't pass small structures in
registers.  Admittedly, several targets would be broken by doing so, so
it's not particularly urgent.

-Nathan

Re: [Qemu-devel] [PATCH] target-arm/helper.c: For float-int conversion helpers pass ints as ints

[Peter Maydell]

On 21 March 2011 14:09, Nathan Froyd <froydnj@codesourcery.com> wrote:
> I'm just concerned about what would happen if we turned on softfloat's
> "float types are structure types" bit; I'm pretty sure everything would
> break horribly on targets that don't pass small structures in
> registers.  Admittedly, several targets would be broken by doing so, so
> it's not particularly urgent.

Last time I turned that flag on half the targets didn't compile :-)
I view it as more of a debugging aid and wouldn't expect anybody to
ever actually run with it enabled.

-- PMM