[Qemu-devel] [PATCH] target-mips: update writing to CP0.Status.KX/SX/UX in MIPS Release R6

[Leon Alrae]

Implement the relationship between CP0.Status.KX, SX and UX. It should not
be possible to set UX bit if SX is 0, the same applies for setting SX if
KX is 0.

Signed-off-by: Leon Alrae <address@hidden>
---
 target-mips/cpu.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/target-mips/cpu.h b/target-mips/cpu.h
index 210370e..de8380c 100644
--- a/target-mips/cpu.h
+++ b/target-mips/cpu.h
@@ -1003,7 +1003,12 @@ static inline void cpu_mips_store_status(CPUMIPSState 
*env, target_ulong val)
 
     if (env->insn_flags & ISA_MIPS32R6) {
         bool has_supervisor = extract32(mask, CP0St_KSU, 2) == 0x3;
-
+#if defined(TARGET_MIPS64)
+        uint32_t ksux = (1 << CP0St_KX) & val;
+        ksux |= (ksux >> 1) & val; /* KX = 0 forces SX to be 0 */
+        ksux |= (ksux >> 1) & val; /* SX = 0 forces UX to be 0 */
+        val = (val & ~(7 << CP0St_UX)) | ksux;
+#endif
         if (has_supervisor && extract32(val, CP0St_KSU, 2) == 0x3) {
             mask &= ~(3 << CP0St_KSU);
         }
-- 
2.1.0