[RFC PATCH] RISC-V: Save mmu_idx using FIELD_DP32 not OR

[Christoph Muellner]

From: Christoph Müllner <christoph.muellner@vrull.eu>

Setting flags using OR might work, but is not optimal
for a couple of reasons:
* No way grep for stores to the field MEM_IDX.
* The return value of cpu_mmu_index() is not masked
  (not a real problem as long as cpu_mmu_index() returns only valid values).
* If the offset of MEM_IDX would get moved to non-0, then this code
  would not work anymore.

Let's use the FIELD_DP32() macro instead of the OR, which is already
used for most other flags.

Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
---
 target/riscv/cpu_helper.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 278d163803..d68b6b351d 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -80,7 +80,8 @@ void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong 
*pc,
     flags |= TB_FLAGS_MSTATUS_FS;
     flags |= TB_FLAGS_MSTATUS_VS;
 #else
-    flags |= cpu_mmu_index(env, 0);
+    flags = FIELD_DP32(flags, TB_FLAGS, MEM_IDX, cpu_mmu_index(env, 0));
+
     if (riscv_cpu_fp_enabled(env)) {
         flags |= env->mstatus & MSTATUS_FS;
     }
-- 
2.38.1