Hello *, While working on integer-gmp2 I noticed that there seems to be redundant code between rts/StgPrimFloat.c and integer-gmp. Specifically, there's a void __decodeDouble_2Int (I_ *man_sign, W_ *man_high, W_ *man_low, I_ *exp, StgDouble dbl); C implementation which does some low-level bit-fiddling on the IEEE representation instead of just using the more portable standard frexp() function, like I'm doing in integer-gmp2, e.g.: HsInt ​integer_gmp_decode_double (const HsDouble x, HsInt64 *const mantisse) ​{ ​ if (x) { ​ int exp = 0; *mantisse = (HsInt64)scalbn(frexp(x, &exp), DBL_MANT_DIG); ​ return exp-DBL_MANT_DIG; ​ } else { ​ *mantisse = 0; ​ return 0; ​ } ​} A similiar operation exists in integer-gmp/cbits/float.c So here's my questions: 1) Is there any reason/value in doing low-level IEEE bit-fiddling instead of just delegating to the C99/POSIX compliant frexp(3) operations? 2) Specifically, `decodeDouble_2Int` seems to be dead-code. I'd like to instead move the HsInt ​integer_gmp_decode_double (const HsDouble x, HsInt64 *const mantisse); which I currently import as #if WORD_SIZE_IN_BITS == 32 foreign import prim "integer_gmp_cmm_decode_double" cmm_decode_double :: Double# -> (# Int64#, Int# #) #elif WORD_SIZE_IN_BITS == 64 foreign import prim "integer_gmp_cmm_decode_double" cmm_decode_double :: Double# -> (# Int#, Int# #) #endif based on the size of `Int#` into rts/PrimOps.cmm & rts/StgPrimFloat.c as that may allow me to avoid any C-- in integer-gmp2 altogether (as I only need to go via C-- to return an unboxed pair) Cheers, hvr