Re: floating-point loads vs dreamcast
der Mouse <[email protected]> Sat, 14 May 2011 00:19:36 -0400 (EDT)
| Newsgroups | gmane.os.netbsd.ports.dreamcast |
|---|---|
| Message-ID | <[email protected]> |
>> Any idea what's going on here? As I read the hardware docs, >> fmov @rN,drM certainly ought to do a 64-bit double-precision load. > Only if you set SZ to 1. PR controls the size of arithmetic > operations, SZ controls the size of loads and stores. Well, my notes say | When the manual says "SZ 0", it means "SZ=0 and PR=0", and when it says | "SZ 1", it means "(SZ=1 and PR=0) or (SZ=0 and PR=1)". (This learned | from Marcus Comstedt on port-dreamcast.) Did I misunderstand you, or is this true generally but not true of fmov, or what? I can't just set SZ; the doc specifically calls out SZ=1 PR=1 as an invalid combination, so I'd have to clear PR. And it seems..odd..to design an FPU which requires changing settings to both do arithmetic on double-precision numbers and load and store double-precision numbers. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML [email protected] / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B