On 07/14/16 19:14, Paolo Bonzini wrote: > > > On 14/07/2016 19:11, Laszlo Ersek wrote: >> * I didn't say, but I also tried "mov ax, ds". The SDM writes, "The >> upper 56 bits or 48 bits (respectively) of the destination >> general-purpose register are not modified by the operation". In this >> context, those bits were known to be zero, and I hoped that NASM 2.07 >> might support a 16->16 MOV. >> >> I vaguely recall that I tried "mov eax, ds" too (it may have been my >> very first try, I don't remember any longer). I think "mov ax, ds" was >> my second try, and "movzx eax, ds" the third?... >> >> However, none of these work, because NASM 2.07 (apparently) lacks the >> *general* ability to MOV from/to segment registers in 64-bit mode. > > Ugh, this is so wrong. :) I guess you could also use a macro that > expands to > > bits 32 > mov src, dst > bits 64 > > because the encoding is the same in 32-bit and 64-bit.
Nice trick :), but the point of using NASM would be to avoid such hacks, and to say what we mean, on Windows and Linux build hosts identically. Thanks! Laszlo _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
