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| author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2008-11-13 00:15:08 +0000 |
|---|---|---|
| committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2008-11-13 00:15:08 +0000 |
| commit | 15b4c567c5a1fc40aa6d9de04cc5becc32df3641 (patch) | |
| tree | 50145e6635af5197777618c2c54b9d9593ef0f90 | |
| parent | 605bc460d02638bb5321af77e80d169f8807176f (diff) | |
| download | nuttx-15b4c567c5a1fc40aa6d9de04cc5becc32df3641.tar.gz nuttx-15b4c567c5a1fc40aa6d9de04cc5becc32df3641.tar.bz2 nuttx-15b4c567c5a1fc40aa6d9de04cc5becc32df3641.zip | |
No need to restore r8-r14 on return from int if no context switch
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1213 42af7a65-404d-4744-a932-0658087f49c3
| -rw-r--r-- | nuttx/arch/sh/src/sh1/sh1_vector.S | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/nuttx/arch/sh/src/sh1/sh1_vector.S b/nuttx/arch/sh/src/sh1/sh1_vector.S index 3e6a32029..9e7ef5075 100644 --- a/nuttx/arch/sh/src/sh1/sh1_vector.S +++ b/nuttx/arch/sh/src/sh1/sh1_vector.S @@ -345,7 +345,7 @@ _up_vector: mov.l .Ldoirq, r0 jsr @r0 - mov r15, r14 + nop /* Recover the user stack point */ @@ -355,7 +355,7 @@ _up_vector: mov.l .Ldoirq, r0 jsr @r0 - mov r15, r14 + nop #endif /* On return, R0 holds the address of the base of the XCPTCONTEXT * structure to use for the return -- may not be the same as the @@ -368,17 +368,28 @@ _up_vector: bf .Lcontextswitch mov r0, r15 - /* Restore registers from the stack. */ + /* Restore registers from the stack. NOTE: We coudl improve interrupt + * performance by skipping the restore of r8-r14. These will not + * be modified by the called C code + */ - mov.l @r15+, r8 /* 0-8: r8-r14, pr, and gbr */ +#if 1 + /* Skip over static registers -- these will not be modified by the + * called C code (r8-r14) + */ + + add #(7*4), r15 /* 0-6: Skip over r8-r14 */ +#else + mov.l @r15+, r8 /* 0-6: r8-r14 */ mov.l @r15+, r9 mov.l @r15+, r10 mov.l @r15+, r11 mov.l @r15+, r12 mov.l @r15+, r13 mov.l @r15+, r14 +#endif - lds.l @r15+, pr + lds.l @r15+, pr /* 7-8: pr and gbr */ ldc.l @r15+, gbr add #4, r15 /* 9: Skip SP restore */ |