Are there unsigned equivalents of the x87 FILD and SSE CVTSI2SD instructions?

Question

I want to implement the equivalent of C\'s uint-to-double cast in the GHC Haskell compiler. We already implement int-to-double

Answer 1

We already implement int-to-double using FILD ...
Is there unsigned versions of these operations

If you want exactly x87 FILD opcode to use, just shift uint64 to uint63 (div 2) and then mul it by 2 back, but already as double, so the x87 uint64-to-double conversion requires one FMUL execution in overhead.

The example: 0xFFFFFFFFFFFFFFFFU -> +1.8446744073709551e+0019

it was unable to post the code example in the strict form rules. I'll try later.

    //inline
    double    u64_to_d(unsigned _int64 v){

    //volatile double   res;
    volatile unsigned int tmp=2;
    _asm{
    fild  dword ptr tmp
    //v>>=1;
    shr   dword ptr v+4, 1
    rcr   dword ptr v, 1
    fild  qword ptr v

    //save lsb
    //mov   byte ptr tmp, 0  
    //rcl   byte ptr tmp, 1

    //res=tmp+res*2;
    fmulp st(1),st
    //fild  dword ptr tmp
    //faddp st(1),st 

    //fstp  qword ptr res
    }

    //return res;
    //fld  qword ptr res
}

VC produced x86 output

        //inline
        double    u64_to_d(unsigned _int64 v){
    55                   push        ebp  
    8B EC                mov         ebp,esp  
    81 EC 04 00 00 00    sub         esp,04h  

        //volatile double   res;
        volatile unsigned int tmp=2;
    C7 45 FC 02 00 00 00 mov         dword ptr [tmp], 2  
        _asm{
        fild  dword ptr tmp
    DB 45 FC             fild        dword ptr [tmp]  
        //v>>=1;
        shr   dword ptr v+4, 1
    D1 6D 0C             shr         dword ptr [ebp+0Ch],1  
        rcr   dword ptr v, 1
    D1 5D 08             rcr         dword ptr [v],1  
        fild  qword ptr v
    DF 6D 08             fild        qword ptr [v]  

        //save lsb
    //    mov   byte ptr [tmp], 0  
    //C6 45 FC 00        mov         byte ptr [tmp], 0
    //    rcl   byte ptr tmp, 1
    //D0 55 FC           rcl         byte ptr [tmp],1  

        //res=tmp+res*2;
        fmulp st(1),st
    DE C9                fmulp       st(1),st  
    //    fild  dword ptr tmp
    //DB 45 FC           fild        dword ptr [tmp]  
    //    faddp st(1),st 
    //DE C1              faddp       st(1),st  


        //fstp  qword ptr res
        //fstp        qword ptr [res]  
    }

        //return res;
        //fld         qword ptr [res]  

    8B E5                mov         esp,ebp  
    5D                   pop         ebp  
    C3                   ret  
}

i posted (probably i manually removed all incorrected ascii chars in text file).