[fpc-devel] FPC Performance: MOVAPD vs MOVSD

[Jonas Maebe]

On 19 Oct 2011, at 15:45, Graeme Geldenhuys wrote:

> Not that I understand much of the assembler generated, but what I did
> notice is that Delphi XE2 64-bit uses the MOVAPD function (introduced in
> SSE2 [1]), but even if I specify -O3 -CfSSE3 with 64-bit FPC, FPC only
> uses the MOVSD (introduced in 386 [2]).

The movsd instruction you are thinking of is something completely different (and would appear as "movsl" in the assembler code, because it uses AT&T syntax). The movsd that FPC uses is an SSE2 instruction.


Jonas