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target/ppc: Introduce fp number classification

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Having a separate, logical classifiation of numbers will
unify more error paths for different formats.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Richard Henderson 2018-10-11 16:41:55 -07:00 committed by David Gibson
parent 6525aadc12
commit 0394d7a684
1 changed files with 51 additions and 43 deletions
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98
target/ppc/fpu_helper.c
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@ -114,54 +114,62 @@ static inline int ppc_float64_get_unbiased_exp(float64 f)
return ((f >> 52) & 0x7FF) - 1023;
}
/* 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 ret = tp##_is_neg(arg) * is_neg; \
if (unlikely(tp##_is_any_nan(arg))) { \
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))) { \
ret |= is_inf; \
} else if (tp##_is_zero(arg)) { \
ret |= is_zero; \
} else if (tp##_is_zero_or_denormal(arg)) { \
ret |= is_denormal; \
} else { \
ret |= is_normal; \
} \
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) \
{ \
int isneg; \
int fprf; \
\
isneg = tp##_is_neg(arg); \
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; \
} \
} else if (unlikely(tp##_is_infinity(arg))) { \
/* +/- infinity */ \
if (isneg) { \
fprf = 0x09; \
} else { \
fprf = 0x05; \
} \
} 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; \
} \
} \
} \
/* We update FPSCR_FPRF */ \
env->fpscr &= ~(0x1F << FPSCR_FPRF); \
env->fpscr |= fprf << FPSCR_FPRF; \
set_fprf_from_class(env, tp##_classify(arg)); \
}
COMPUTE_FPRF(float16)