* try to fix precision error on x86 platform step7.

Author: IRainman

include/fast_float/decimal_to_binary.h

@@ -139,8 +139,9 @@ compute_float(int64_t q, uint64_t w) noexcept {
   // branchless approach: value128 product = compute_product(q, w); but in
   // practice, we can win big with the compute_product_approximation if its
   // additional branch is easily predicted. Which is best is data specific.
-  limb_t upperbit = limb_t(product.high >> 63);
-  limb_t shift = limb_t(upperbit + 64 - binary::mantissa_explicit_bits() - 3);
+  am_pow_t const upperbit = am_pow_t(product.high >> 63);
+  am_pow_t const shift =
+      am_pow_t(upperbit + 64 - binary::mantissa_explicit_bits() - 3);
 
   answer.mantissa = product.high >> shift;
 

include/fast_float/float_common.h

@@ -446,8 +446,7 @@ typedef int_fast8_t am_bits_t;
 
 // Power bias is signed for handling a denormal float
 // or an invalid mantissa.
-typedef int16_t am_pow_t; // can't be int_fast16_t because invalid_am_bias
-                          // hacks. Needs rewriting this.
+typedef int32_t am_pow_t;
 
 // Bias so we can get the real exponent with an invalid adjusted_mantissa.
 constexpr static am_pow_t invalid_am_bias = -0x8000;