[Libre-soc-isa] [Bug 650] write rfc for OpenPower fpr <-> gpr moves/conversions

[bugzilla-daemon at libre-soc.org]

https://bugs.libre-soc.org/show_bug.cgi?id=650

--- Comment #20 from Luke Kenneth Casson Leighton <lkcl at lkcl.net> ---
hmmm, given that the "standard" way of doing fp conversion is not
equal to how OpenPOWER does it, i think it would be highly illustrative
to also include c as well, in the appendix
https://libre-soc.org/openpower/sv/int_fp_mv/appendix/

i'm assuming there that c implements "standard" IEEE754.

added:


toInt32(double):
        fctiwz 1,1
        addi 9,1,-16
        stfiwx 1,0,9
        lwz 3,-16(1)
        extsw 3,3
        blr
        .long 0
        .byte 0,9,0,0,0,0,0,0

which is still pretty awful.  5 instructions including a LD/ST, which
gets 2 other registers involved plus some local stack.

-- 
You are receiving this mail because:
You are on the CC list for the bug.