gistfile1.txt

End result will be:

/* CPU dependent mtc0 hazard hook */
#if (MIPS32R2 + MIPS64R2) > 0
# define COP0_SYNC              .set push; .set mips32r2; ehb; .set pop
# define JR_HB_RA               .set push; .set mips32r2; jr.hb ra; nop; .set pop
#else
# define COP0_SYNC              sll $0,$0,1; sll $0,$0,1; sll $0,$0,1
# define JR_HB_RA               sll $0,$0,1; sll $0,$0,1; jr ra; sll $0,$0,1
#endif
#define COP0_HAZARD_FPUENABLE   nop; nop; nop; nop;

Make sure we use sll rather than nop, which is used
out of paranoia that .set reorder will get rid of
the nops (as it likely doesn't know about COP0 hazards).

MIPSnnR2 or newer has ehb/jr.hb to take care of all
our worries about cop0 hazards.

It's completely safe but potentially wasteful - unclear
why we have a case of less padding for very old archs
(MIPS1-2? when the macros are defined is vague.)


diff --git a/sys/arch/mips/include/cpuregs.h b/sys/arch/mips/include/cpuregs.h
index 38905ee..99b4f4d 100644
--- a/sys/arch/mips/include/cpuregs.h
+++ b/sys/arch/mips/include/cpuregs.h
@@ -152,22 +152,11 @@
 
 /* CPU dependent mtc0 hazard hook */
 #if (MIPS32R2 + MIPS64R2) > 0
-# if (MIPS1 + MIPS3 + MIPS32 + MIPS64) == 0
-#  define COP0_SYNC		sll $0,$0,3	/* EHB */
-#  define JR_HB_RA		.set push; .set mips32r2; jr.hb ra; nop; .set pop
-# else
-#  define COP0_SYNC		sll $0,$0,1; sll $0,$0,1; sll $0,$0,3
-#  define JR_HB_RA		sll $0,$0,1; sll $0,$0,1; jr ra; sll $0,$0,3
-# endif
-#elif (MIPS32 + MIPS64) > 0
-# define COP0_SYNC		sll $0,$0,1; sll $0,$0,1; sll $0,$0,1
-# define JR_HB_RA		sll $0,$0,1; sll $0,$0,1; jr ra; sll $0,$0,1
-#elif MIPS3 > 0
-# define COP0_SYNC		nop; nop; nop
-# define JR_HB_RA		nop; nop; jr ra; nop
+# define COP0_SYNC		.set push; .set mips32r2; ehb; .set pop
+# define JR_HB_RA		.set push; .set mips32r2; jr.hb ra; nop; .set pop
 #else
-# define COP0_SYNC		nop
-# define JR_HB_RA		jr ra; nop
+# define COP0_SYNC		sll $0,$0,1; sll $0,$0,1; sll $0,$0,1
+# define JR_HB_RA		sll $0,$0,1; sll $0,$0,1; jr ra; sll $0,$0,1
 #endif
 #define	COP0_HAZARD_FPUENABLE	nop; nop; nop; nop;