[PATCH v4 6/6] target/ppc: Better CTRL SPR implementation

[Nicholas Piggin <npiggin@gmail.com>]

The CTRL register is able to write bit zero, and that is reflected in a
bit field in the register that reflects the state of all threads in the
core.

TCG does not implement SMT, so this just requires mirroring that bit into
the first bit of the thread state field.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/translate.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index 9b7884586c..b6bab4c234 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -425,7 +425,14 @@ void spr_write_generic32(DisasContext *ctx, int sprn, int gprn)
 
 void spr_write_CTRL(DisasContext *ctx, int sprn, int gprn)
 {
-    spr_write_generic32(ctx, sprn, gprn);
+    /* This does not implement >1 thread */
+    TCGv t0 = tcg_temp_new();
+    TCGv t1 = tcg_temp_new();
+    tcg_gen_extract_tl(t0, cpu_gpr[gprn], 0, 1); /* Extract RUN field */
+    tcg_gen_shli_tl(t1, t0, 8); /* Duplicate the bit in TS */
+    tcg_gen_or_tl(t1, t1, t0);
+    gen_store_spr(sprn, t1);
+    spr_store_dump_spr(sprn);
 
     /*
      * SPR_CTRL writes must force a new translation block,
-- 
2.40.1