310 #define Sglext_setzero(valA,valB)	\  argument
311     Sextallp1(valA) = 0; Sextallp2(valB) = 0
317 #define Sglext_iszero(valA,valB) (Sextallp1(valA)==0 && Sextallp2(valB)==0)  argument
380 #define Sglext_leftshiftby8(valA,valB) \  argument
381     Shiftdouble(Sextallp1(valA),Sextallp2(valB),24,Sextallp1(valA)); \
383 #define Sglext_leftshiftby4(valA,valB) \  argument
384     Shiftdouble(Sextallp1(valA),Sextallp2(valB),28,Sextallp1(valA)); \
386 #define Sglext_leftshiftby3(valA,valB) \  argument
387     Shiftdouble(Sextallp1(valA),Sextallp2(valB),29,Sextallp1(valA)); \
389 #define Sglext_leftshiftby2(valA,valB) \  argument
390     Shiftdouble(Sextallp1(valA),Sextallp2(valB),30,Sextallp1(valA)); \
392 #define Sglext_leftshiftby1(valA,valB) \  argument
393     Shiftdouble(Sextallp1(valA),Sextallp2(valB),31,Sextallp1(valA)); \