* [PATCH] parisc: optimize mtsp(0,sr) inline assembly
@ 2013-06-29 20:08 Helge Deller
0 siblings, 0 replies; only message in thread
From: Helge Deller @ 2013-06-29 20:08 UTC (permalink / raw)
To: linux-parisc, James Bottomley
If the value which should be moved into a space register is zero, we can
optimize the inline assembly to become "mtsp %r0,%srX".
Signed-off-by: Helge Deller <deller@gmx.de>
diff --git a/arch/parisc/include/asm/special_insns.h b/arch/parisc/include/asm/special_insns.h
index d306b75..e150930 100644
--- a/arch/parisc/include/asm/special_insns.h
+++ b/arch/parisc/include/asm/special_insns.h
@@ -32,9 +32,12 @@ static inline void set_eiem(unsigned long val)
cr; \
})
-#define mtsp(gr, cr) \
- __asm__ __volatile__("mtsp %0,%1" \
+#define mtsp(val, cr) \
+ { if (__builtin_constant_p(val) && ((val) == 0)) \
+ __asm__ __volatile__("mtsp %%r0,%0" : : "i" (cr) : "memory"); \
+ else \
+ __asm__ __volatile__("mtsp %0,%1" \
: /* no outputs */ \
- : "r" (gr), "i" (cr) : "memory")
+ : "r" (val), "i" (cr) : "memory"); }
#endif /* __PARISC_SPECIAL_INSNS_H */
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2013-06-29 20:08 [PATCH] parisc: optimize mtsp(0,sr) inline assembly Helge Deller
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