[GitHub] [incubator-nuttx] Ouss4 commented on a change in pull request #5248: xtensa: some fixes in interrupt handler

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Ouss4 commented on a change in pull request #5248:
URL: https://github.com/apache/incubator-nuttx/pull/5248#discussion_r787043847



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File path: arch/xtensa/src/common/xtensa_int_handlers.S
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@@ -312,6 +312,7 @@ _xtensa_level1_handler:
 
 	s32i	a2, sp, (4 * REG_A2)
 	mov		a2, sp							      /* Address of state save on stack */
+	s32i	a3, sp, (4 * REG_A3)

Review comment:
       The commit message says that this is similar to `_xtensa_syscall_handler`, it's actually not similar.  In `_xtensa_syscall_handler` we use A3 (and A2) as scratch registers before calling `_xtensa_save_context`, so they are saved.
   Another thing to note regarding `_xtensa_syscall_handler` is that it never restores the first saved A3, but just calls `_xtensa_restore_context` which restores a scratch version of A3 only.
   
   I think when @zhuyanlinzyl removed the A3 save from `_xtensa_save_context` it fixes the issue he had, but I believe we need to organise this a bit more. I think we should fix how `_xtensa_syscall_handler` restores A3.




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