diff options
Diffstat (limited to 'target/ppc/fpu_helper.c')
| -rw-r--r-- | target/ppc/fpu_helper.c | 61 |
1 files changed, 49 insertions, 12 deletions
diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c index 5af5241ab0..b9bb1b856e 100644 --- a/target/ppc/fpu_helper.c +++ b/target/ppc/fpu_helper.c @@ -47,24 +47,61 @@ static inline bool fp_exceptions_enabled(CPUPPCState *env) /*****************************************************************************/ /* Floating point operations helpers */ -uint64_t helper_float32_to_float64(CPUPPCState *env, uint32_t arg) + +/* + * This is the non-arithmatic conversion that happens e.g. on loads. + * In the Power ISA pseudocode, this is called DOUBLE. + */ +uint64_t helper_todouble(uint32_t arg) { - CPU_FloatU f; - CPU_DoubleU d; + uint32_t abs_arg = arg & 0x7fffffff; + uint64_t ret; - f.l = arg; - d.d = float32_to_float64(f.f, &env->fp_status); - return d.ll; + if (likely(abs_arg >= 0x00800000)) { + /* Normalized operand, or Inf, or NaN. */ + ret = (uint64_t)extract32(arg, 30, 2) << 62; + ret |= ((extract32(arg, 30, 1) ^ 1) * (uint64_t)7) << 59; + ret |= (uint64_t)extract32(arg, 0, 30) << 29; + } else { + /* Zero or Denormalized operand. */ + ret = (uint64_t)extract32(arg, 31, 1) << 63; + if (unlikely(abs_arg != 0)) { + /* Denormalized operand. */ + int shift = clz32(abs_arg) - 9; + int exp = -126 - shift + 1023; + ret |= (uint64_t)exp << 52; + ret |= abs_arg << (shift + 29); + } + } + return ret; } -uint32_t helper_float64_to_float32(CPUPPCState *env, uint64_t arg) +/* + * This is the non-arithmatic conversion that happens e.g. on stores. + * In the Power ISA pseudocode, this is called SINGLE. + */ +uint32_t helper_tosingle(uint64_t arg) { - CPU_FloatU f; - CPU_DoubleU d; + int exp = extract64(arg, 52, 11); + uint32_t ret; - d.ll = arg; - f.f = float64_to_float32(d.d, &env->fp_status); - return f.l; + if (likely(exp > 896)) { + /* No denormalization required (includes Inf, NaN). */ + ret = extract64(arg, 62, 2) << 30; + ret |= extract64(arg, 29, 30); + } else { + /* Zero or Denormal result. If the exponent is in bounds for + * a single-precision denormal result, extract the proper bits. + * If the input is not zero, and the exponent is out of bounds, + * then the result is undefined; this underflows to zero. + */ + ret = extract64(arg, 63, 1) << 31; + if (unlikely(exp >= 874)) { + /* Denormal result. */ + ret |= ((1ULL << 52) | extract64(arg, 0, 52)) >> (896 + 30 - exp); + } + } + return ret; } static inline int ppc_float32_get_unbiased_exp(float32 f) |