target/ppc: Introduce fp number classification
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>
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@ -114,54 +114,62 @@ static inline int ppc_float64_get_unbiased_exp(float64 f)
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return ((f >> 52) & 0x7FF) - 1023;
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}
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/* Classify a floating-point number. */
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enum {
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is_normal = 1,
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is_zero = 2,
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is_denormal = 4,
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is_inf = 8,
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is_qnan = 16,
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is_snan = 32,
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is_neg = 64,
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};
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#define COMPUTE_CLASS(tp) \
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static int tp##_classify(tp arg) \
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{ \
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int ret = tp##_is_neg(arg) * is_neg; \
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if (unlikely(tp##_is_any_nan(arg))) { \
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float_status dummy = { }; /* snan_bit_is_one = 0 */ \
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ret |= (tp##_is_signaling_nan(arg, &dummy) \
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? is_snan : is_qnan); \
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} else if (unlikely(tp##_is_infinity(arg))) { \
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ret |= is_inf; \
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} else if (tp##_is_zero(arg)) { \
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ret |= is_zero; \
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} else if (tp##_is_zero_or_denormal(arg)) { \
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ret |= is_denormal; \
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} else { \
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ret |= is_normal; \
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} \
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return ret; \
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}
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COMPUTE_CLASS(float16)
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COMPUTE_CLASS(float32)
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COMPUTE_CLASS(float64)
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COMPUTE_CLASS(float128)
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static void set_fprf_from_class(CPUPPCState *env, int class)
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{
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static const uint8_t fprf[6][2] = {
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{ 0x04, 0x08 }, /* normalized */
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{ 0x02, 0x12 }, /* zero */
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{ 0x14, 0x18 }, /* denormalized */
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{ 0x05, 0x09 }, /* infinity */
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{ 0x11, 0x11 }, /* qnan */
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{ 0x00, 0x00 }, /* snan -- flags are undefined */
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};
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bool isneg = class & is_neg;
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env->fpscr &= ~(0x1F << FPSCR_FPRF);
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env->fpscr |= fprf[ctz32(class)][isneg] << FPSCR_FPRF;
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}
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#define COMPUTE_FPRF(tp) \
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void helper_compute_fprf_##tp(CPUPPCState *env, tp arg) \
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{ \
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int isneg; \
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int fprf; \
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\
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isneg = tp##_is_neg(arg); \
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if (unlikely(tp##_is_any_nan(arg))) { \
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if (tp##_is_signaling_nan(arg, &env->fp_status)) { \
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/* Signaling NaN: flags are undefined */ \
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fprf = 0x00; \
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} else { \
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/* Quiet NaN */ \
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fprf = 0x11; \
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} \
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} else if (unlikely(tp##_is_infinity(arg))) { \
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/* +/- infinity */ \
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if (isneg) { \
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fprf = 0x09; \
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} else { \
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fprf = 0x05; \
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} \
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} else { \
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if (tp##_is_zero(arg)) { \
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/* +/- zero */ \
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if (isneg) { \
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fprf = 0x12; \
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} else { \
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fprf = 0x02; \
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} \
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} else { \
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if (tp##_is_zero_or_denormal(arg)) { \
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/* Denormalized numbers */ \
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fprf = 0x10; \
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} else { \
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/* Normalized numbers */ \
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fprf = 0x00; \
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} \
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if (isneg) { \
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fprf |= 0x08; \
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} else { \
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fprf |= 0x04; \
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} \
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} \
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} \
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/* We update FPSCR_FPRF */ \
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env->fpscr &= ~(0x1F << FPSCR_FPRF); \
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env->fpscr |= fprf << FPSCR_FPRF; \
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set_fprf_from_class(env, tp##_classify(arg)); \
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}
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COMPUTE_FPRF(float16)
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