target/xtensa: move WINDOW_BASE SR update to postprocessing

Opcodes that modify WINDOW_BASE SR don't have dependency on opcodes that
use windowed registers. If such opcodes are combined in a single
instruction they may not be correctly ordered. Instead of adding said
dependency use temporary register to store changed WINDOW_BASE value and
do actual register window rotation as a postprocessing step.
Not all opcodes that change WINDOW_BASE need this: retw, rfwo and rfwu
are also jump opcodes, so they are guaranteed to be translated last and
thus will not affect other opcodes in the same instruction.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

1 files changed, 4 insertions, 10 deletions

diff --git a/target/xtensa/win_helper.c b/target/xtensa/win_helper.c
index 7d793d4..d7a4e27 100644
--- a/target/xtensa/win_helper.c
+++ b/target/xtensa/win_helper.c
@@ -96,9 +96,9 @@ void xtensa_rotate_window(CPUXtensaState *env, uint32_t delta)
     xtensa_rotate_window_abs(env, env->sregs[WINDOW_BASE] + delta);
 }
 
-void HELPER(wsr_windowbase)(CPUXtensaState *env, uint32_t v)
+void HELPER(sync_windowbase)(CPUXtensaState *env)
 {
-    xtensa_rotate_window_abs(env, v);
+    xtensa_rotate_window_abs(env, env->windowbase_next);
 }
 
 void HELPER(entry)(CPUXtensaState *env, uint32_t pc, uint32_t s, uint32_t imm)
@@ -106,9 +106,8 @@ void HELPER(entry)(CPUXtensaState *env, uint32_t pc, uint32_t s, uint32_t imm)
     int callinc = (env->sregs[PS] & PS_CALLINC) >> PS_CALLINC_SHIFT;
 
     env->regs[(callinc << 2) | (s & 3)] = env->regs[s] - imm;
-    xtensa_rotate_window(env, callinc);
-    env->sregs[WINDOW_START] |=
-        windowstart_bit(env->sregs[WINDOW_BASE], env);
+    env->windowbase_next = env->sregs[WINDOW_BASE] + callinc;
+    env->sregs[WINDOW_START] |= windowstart_bit(env->windowbase_next, env);
 }
 
 void HELPER(window_check)(CPUXtensaState *env, uint32_t pc, uint32_t w)
@@ -196,11 +195,6 @@ uint32_t HELPER(retw)(CPUXtensaState *env, uint32_t pc)
     return ret_pc;
 }
 
-void HELPER(rotw)(CPUXtensaState *env, uint32_t imm4)
-{
-    xtensa_rotate_window(env, imm4);
-}
-
 void xtensa_restore_owb(CPUXtensaState *env)
 {
     xtensa_rotate_window_abs(env, (env->sregs[PS] & PS_OWB) >> PS_OWB_SHIFT);