[OpenBIOS] [PATCH] SPARC32 : WIM register update delay

[Olivier DANET]

The SparcV8 standard states, page 134 : 
"If any of the three instructions after a write state register instruction reads any field
 that was changed by the original write state register instruction, the contents of that
 field read by that instruction are undefined."
The restore instruction depends on the %WIM register, three NOPs must be inserted.

diff a/openbios-devel/arch/sparc32/wuf.S b/openbios-devel/arch/sparc32/wuf.S
--- a/openbios-devel/arch/sparc32/wuf.S
+++ b/openbios-devel/arch/sparc32/wuf.S
@@ -121,7 +121,7 @@ fnwin_patch1:       srl     %t_wim, 7, %twin_tmp2
 fnwin_patch2:  and     %twin_tmp1, 0xff, %twin_tmp1
 
        wr      %twin_tmp1, 0x0, %wim   /* Make window 'I' invalid */
-
+    WRITE_PAUSE
        restore %g0, %g0, %g0           /* Restore to window 'O' */
 
        /* Trapped from kernel, we trust that the kernel does not

Signed-off-by: Olivier DANET <odanet at caramail.com>