=====Converting 40-bit floats to 64-bit floats=====

//by Richard Russell, August 2014//\\ \\  The assembly language routine below converts a 40-bit floating-point value, in the registers **cl edx**, into a 64-bit floating-point ('double') value, in the registers **ecx edx**:\\ 
        movzx   ecx,cl                  ;zero-extend exponent
        add     ecx,895                 ;adjust exponent
        rol     edx,1                   ;move sign to LSB
        shld    ecx,edx,21              ;align exponent
        shl     edx,20                  ;align mantissa
        btr     edx,20                  ;get sign to carry
        rcr     ecx,1                   ;insert sign 
Note that this routine does not deal with **variants** (i.e. a 40-bit value containing an integer rather than a float). To avoid the necessity of providing extra code for this purpose you can convert a variant into a float by multiplying by 1.0 in BASIC thus:\\ 
        var *= 1.0