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tcg: Fix helper function vs host abi for float16

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Depending on the host abi, float16, aka uint16_t, values are
passed and returned either zero-extended in the host register
or with garbage at the top of the host register.

The tcg code generator has so far been assuming garbage, as that
matches the x86 abi, but this is incorrect for other host abis.
Further, target/arm has so far been assuming zero-extended results,
so that it may store the 16-bit value into a 32-bit slot with the
high 16-bits already clear.

Rectify both problems by mapping "f16" in the helper definition
to uint32_t instead of (a typedef for) uint16_t.  This forces
the host compiler to assume garbage in the upper 16 bits on input
and to zero-extend the result on output.

Cc: qemu-stable@nongnu.org
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Message-id: 20180522175629.24932-1-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Richard Henderson 2018-05-31 14:50:51 +01:00 • committed by Peter Maydell
parent 34ffacae08
commit 6c2be133a7
3 changed files with 59 additions and 58 deletions
Download patch file Download diff file Expand all files Collapse all files

80
target/arm/helper.c
View file

@ -11344,35 +11344,35 @@ DO_VFP_cmp(d, float64)
/* Integer to float and float to integer conversions */
#define CONV_ITOF(name, fsz, sign) \
float##fsz HELPER(name)(uint32_t x, void *fpstp) \
{ \
float_status *fpst = fpstp; \
return sign##int32_to_##float##fsz((sign##int32_t)x, fpst); \
#define CONV_ITOF(name, ftype, fsz, sign) \
ftype HELPER(name)(uint32_t x, void *fpstp) \
{ \
float_status *fpst = fpstp; \
return sign##int32_to_##float##fsz((sign##int32_t)x, fpst); \
}
#define CONV_FTOI(name, fsz, sign, round) \
uint32_t HELPER(name)(float##fsz x, void *fpstp) \
{ \
float_status *fpst = fpstp; \
if (float##fsz##_is_any_nan(x)) { \
float_raise(float_flag_invalid, fpst); \
return 0; \
} \
return float##fsz##_to_##sign##int32##round(x, fpst); \
#define CONV_FTOI(name, ftype, fsz, sign, round) \
uint32_t HELPER(name)(ftype x, void *fpstp) \
{ \
float_status *fpst = fpstp; \
if (float##fsz##_is_any_nan(x)) { \
float_raise(float_flag_invalid, fpst); \
return 0; \
} \
return float##fsz##_to_##sign##int32##round(x, fpst); \
}
#define FLOAT_CONVS(name, p, fsz, sign) \
CONV_ITOF(vfp_##name##to##p, fsz, sign) \
CONV_FTOI(vfp_to##name##p, fsz, sign, ) \
CONV_FTOI(vfp_to##name##z##p, fsz, sign, _round_to_zero)
#define FLOAT_CONVS(name, p, ftype, fsz, sign) \
CONV_ITOF(vfp_##name##to##p, ftype, fsz, sign) \
CONV_FTOI(vfp_to##name##p, ftype, fsz, sign, ) \
CONV_FTOI(vfp_to##name##z##p, ftype, fsz, sign, _round_to_zero)
FLOAT_CONVS(si, h, 16, )
FLOAT_CONVS(si, s, 32, )
FLOAT_CONVS(si, d, 64, )
FLOAT_CONVS(ui, h, 16, u)
FLOAT_CONVS(ui, s, 32, u)
FLOAT_CONVS(ui, d, 64, u)
FLOAT_CONVS(si, h, uint32_t, 16, )
FLOAT_CONVS(si, s, float32, 32, )
FLOAT_CONVS(si, d, float64, 64, )
FLOAT_CONVS(ui, h, uint32_t, 16, u)
FLOAT_CONVS(ui, s, float32, 32, u)
FLOAT_CONVS(ui, d, float64, 64, u)
#undef CONV_ITOF
#undef CONV_FTOI
@ -11465,22 +11465,22 @@ static float16 do_postscale_fp16(float64 f, int shift, float_status *fpst)
return float64_to_float16(float64_scalbn(f, -shift, fpst), true, fpst);
}
float16 HELPER(vfp_sltoh)(uint32_t x, uint32_t shift, void *fpst)
uint32_t HELPER(vfp_sltoh)(uint32_t x, uint32_t shift, void *fpst)
{
return do_postscale_fp16(int32_to_float64(x, fpst), shift, fpst);
}
float16 HELPER(vfp_ultoh)(uint32_t x, uint32_t shift, void *fpst)
uint32_t HELPER(vfp_ultoh)(uint32_t x, uint32_t shift, void *fpst)
{
return do_postscale_fp16(uint32_to_float64(x, fpst), shift, fpst);
}
float16 HELPER(vfp_sqtoh)(uint64_t x, uint32_t shift, void *fpst)
uint32_t HELPER(vfp_sqtoh)(uint64_t x, uint32_t shift, void *fpst)
{
return do_postscale_fp16(int64_to_float64(x, fpst), shift, fpst);
}
float16 HELPER(vfp_uqtoh)(uint64_t x, uint32_t shift, void *fpst)
uint32_t HELPER(vfp_uqtoh)(uint64_t x, uint32_t shift, void *fpst)
{
return do_postscale_fp16(uint64_to_float64(x, fpst), shift, fpst);
}
@ -11504,32 +11504,32 @@ static float64 do_prescale_fp16(float16 f, int shift, float_status *fpst)
}
}
uint32_t HELPER(vfp_toshh)(float16 x, uint32_t shift, void *fpst)
uint32_t HELPER(vfp_toshh)(uint32_t x, uint32_t shift, void *fpst)
{
return float64_to_int16(do_prescale_fp16(x, shift, fpst), fpst);
}
uint32_t HELPER(vfp_touhh)(float16 x, uint32_t shift, void *fpst)
uint32_t HELPER(vfp_touhh)(uint32_t x, uint32_t shift, void *fpst)
{
return float64_to_uint16(do_prescale_fp16(x, shift, fpst), fpst);
}
uint32_t HELPER(vfp_toslh)(float16 x, uint32_t shift, void *fpst)
uint32_t HELPER(vfp_toslh)(uint32_t x, uint32_t shift, void *fpst)
{
return float64_to_int32(do_prescale_fp16(x, shift, fpst), fpst);
}
uint32_t HELPER(vfp_toulh)(float16 x, uint32_t shift, void *fpst)
uint32_t HELPER(vfp_toulh)(uint32_t x, uint32_t shift, void *fpst)
{
return float64_to_uint32(do_prescale_fp16(x, shift, fpst), fpst);
}
uint64_t HELPER(vfp_tosqh)(float16 x, uint32_t shift, void *fpst)
uint64_t HELPER(vfp_tosqh)(uint32_t x, uint32_t shift, void *fpst)
{
return float64_to_int64(do_prescale_fp16(x, shift, fpst), fpst);
}
uint64_t HELPER(vfp_touqh)(float16 x, uint32_t shift, void *fpst)
uint64_t HELPER(vfp_touqh)(uint32_t x, uint32_t shift, void *fpst)
{
return float64_to_uint64(do_prescale_fp16(x, shift, fpst), fpst);
}
@ -11565,7 +11565,7 @@ uint32_t HELPER(set_neon_rmode)(uint32_t rmode, CPUARMState *env)
}
/* Half precision conversions. */
float32 HELPER(vfp_fcvt_f16_to_f32)(float16 a, void *fpstp, uint32_t ahp_mode)
float32 HELPER(vfp_fcvt_f16_to_f32)(uint32_t a, void *fpstp, uint32_t ahp_mode)
{
/* Squash FZ16 to 0 for the duration of conversion. In this case,
* it would affect flushing input denormals.
@ -11578,7 +11578,7 @@ float32 HELPER(vfp_fcvt_f16_to_f32)(float16 a, void *fpstp, uint32_t ahp_mode)
return r;
}
float16 HELPER(vfp_fcvt_f32_to_f16)(float32 a, void *fpstp, uint32_t ahp_mode)
uint32_t HELPER(vfp_fcvt_f32_to_f16)(float32 a, void *fpstp, uint32_t ahp_mode)
{
/* Squash FZ16 to 0 for the duration of conversion. In this case,
* it would affect flushing output denormals.
@ -11591,7 +11591,7 @@ float16 HELPER(vfp_fcvt_f32_to_f16)(float32 a, void *fpstp, uint32_t ahp_mode)
return r;
}
float64 HELPER(vfp_fcvt_f16_to_f64)(float16 a, void *fpstp, uint32_t ahp_mode)
float64 HELPER(vfp_fcvt_f16_to_f64)(uint32_t a, void *fpstp, uint32_t ahp_mode)
{
/* Squash FZ16 to 0 for the duration of conversion. In this case,
* it would affect flushing input denormals.
@ -11604,7 +11604,7 @@ float64 HELPER(vfp_fcvt_f16_to_f64)(float16 a, void *fpstp, uint32_t ahp_mode)
return r;
}
float16 HELPER(vfp_fcvt_f64_to_f16)(float64 a, void *fpstp, uint32_t ahp_mode)
uint32_t HELPER(vfp_fcvt_f64_to_f16)(float64 a, void *fpstp, uint32_t ahp_mode)
{
/* Squash FZ16 to 0 for the duration of conversion. In this case,
* it would affect flushing output denormals.
@ -11742,7 +11742,7 @@ static bool round_to_inf(float_status *fpst, bool sign_bit)
g_assert_not_reached();
}
float16 HELPER(recpe_f16)(float16 input, void *fpstp)
uint32_t HELPER(recpe_f16)(uint32_t input, void *fpstp)
{
float_status *fpst = fpstp;
float16 f16 = float16_squash_input_denormal(input, fpst);
@ -11937,7 +11937,7 @@ static uint64_t recip_sqrt_estimate(int *exp , int exp_off, uint64_t frac)
return extract64(estimate, 0, 8) << 44;
}
float16 HELPER(rsqrte_f16)(float16 input, void *fpstp)
uint32_t HELPER(rsqrte_f16)(uint32_t input, void *fpstp)
{
float_status *s = fpstp;
float16 f16 = float16_squash_input_denormal(input, s);