[GitHub] [incubator-nuttx] xiaoxiang781216 commented on a diff in pull request #6302: xtensa: coproc: modify coproc_save/restore to macro

[GitBox <gi...@apache.org>]

xiaoxiang781216 commented on code in PR #6302:
URL: https://github.com/apache/incubator-nuttx/pull/6302#discussion_r878349648


##########
arch/xtensa/src/common/xtensa_coproc.S:
##########
@@ -89,31 +85,18 @@ _xtensa_coproc_saoffsets:
  *   around the assembly language call to _xtensa_coproc_savestate.
  *
  * Entry Conditions:
- *   - A2 holds the address of current interrupt stack pointer.
+ *   in - Pointer to where the save is performed (e.g. a2)
  *   - Registers have been saved/spilled already.
  *
  * Exit conditions:
  *   - All necessary CP callee-saved state has been saved.
- *   - Registers a2-a7, a13-a15 have been trashed.
- *
- * Must be called from assembly code only, using CALL0.
+ *   - Registers a2-a7, a13-a14 have been trashed.
  *
  ****************************************************************************/
 
-  .global	_xtensa_coproc_savestate
-  .type	_xtensa_coproc_savestate, @function
-
-  .align	4
-  .literal_position
-  .align	4
-
-_xtensa_coproc_savestate:
-
-	/* Move the address of the thread state save area to R15 */
+	.macro xtensa_coproc_savestate in

Review Comment:
   why need in argument? Since xtensa_coproc_savestate already touch many registers(a2-a7, a13-a14), we can directly:
   ```
   .macro xtensa_coproc_savestate
   add a3, sp, (4 * XCPTCONTEXT_REGS)
   ```
   and keep the rest unchanged.



##########
arch/xtensa/src/common/xtensa_context.S:
##########
@@ -66,6 +66,7 @@
 #include <arch/xtensa/xtensa_abi.h>
 #include <arch/xtensa/xtensa_specregs.h>
 
+#include "xtensa_coproc.S"

Review Comment:
   move after line 71



##########
arch/xtensa/src/common/xtensa_coproc.S:
##########
@@ -216,28 +198,15 @@ _xtensa_coproc_savestate:
  *   around the assembly language call to _xtensa_coproc_restorestate.
  *
  * Entry Conditions:
- *   - A2 holds the address of the current interrupt stack pointer.
+ *   in - Pointer to where the save is performed (e.g. a2)
  *
  * Exit conditions:
  *   - All necessary CP callee-saved state has been restored.
- *   - Registers a2-a7, a13-a15 have been trashed.
- *
- * Must be called from assembly code only, using CALL0.
+ *   - Registers a2-a7, a13-a14 have been trashed.
  *
  ****************************************************************************/
 
-	.global	_xtensa_coproc_restorestate
-	.type	_xtensa_coproc_restorestate, @function
-
-	.align	4
-	.literal_position
-	.align	4
-
-_xtensa_coproc_restorestate:
-
-	/* Move the address of the thread state save area to R15 */
-
-	mov		a3, a2				/* A3 is now the address of the save area */
+	.macro xtensa_coproc_restorestate out

Review Comment:
   ditto, let's:
   ```
   .macro xtensa_coproc_restorestate
   addi		a3, a2, (4 * XCPTCONTEXT_REGS)
   ```
   and keep the rest unchanged.



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