[fpc-devel] 64 Bit / 32 Bit

Michael Schnell mschnell at lumino.de
Thu Oct 4 13:31:38 CEST 2007

> No. This was MMX. SSE is always separate.
How does an old OS that does not know about SSE do the task switch ?

> No, it's cutting of old hindering stuff.
If doing Mathematical calculations it of course is best to use the 
format that offers the best accuracy when it's not slower. AFAIK the FPU 
is not slower when doing 80 bit than when doing 64 bit (of course 
loading/storing the values might take some additional cycles). So using 
80 seems like a very sensible option with the given X86 hardware (all 
versions do support 80 bits).


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