REX without REX.W may be different from no REX at all, but in this case it isn't. The push/pop operations ignore REX.W, so the REX prefix is only necessary for high-bits of registers. We use rex_32 for REX with no REX.W, although it should perhaps be called rex_default_operand_size :). On Mon, Jun 22, 2009 at 10:18 AM, <[email protected]> wrote:
> > > http://codereview.chromium.org/141032/diff/1/2 > File src/x64/assembler-x64.cc (right): > > http://codereview.chromium.org/141032/diff/1/2#newcode1197 > Line 1197: emit_rex_64(dst); > On 2009/06/22 07:52:46, Lasse Reichstein wrote: > > If REX.W isn't required, we might as well use > emit_optional_rex_32(dst) > > > It is misleading to the code reader to read rex_32 for an actual 64-bit > move. Actually, REX without REX.W may be diffrerent than no REX at all. > > http://codereview.chromium.org/141032 > > > > -- Lasse R.H. Nielsen / [email protected]'Faith without judgement merely degrades the spirit divine' --~--~---------~--~----~------------~-------~--~----~ v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev -~----------~----~----~----~------~----~------~--~---
