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SH4 ic_cache_invalidate code broken


It came to my attention that the code currently used to invalidate an
instruction cache line may fail to do so if the cache-replacement
chunk of code is not page-aligned.  This patch fixes the problem.  I'm
checking it in mainline and GCC 3.0 branch.

Index: gcc/ChangeLog
from  Alexandre Oliva  <aoliva@redhat.com>

	* config/sh/lib1funcs.asm (ic_invalidate): Align the
	cache-mirroring sequence.  Add nops.

Index: gcc/config/sh/lib1funcs.asm
===================================================================
RCS file: /cvs/gcc/egcs/gcc/config/sh/lib1funcs.asm,v
retrieving revision 1.18
diff -u -p -r1.18 lib1funcs.asm
--- gcc/config/sh/lib1funcs.asm 2001/05/17 03:16:12 1.18
+++ gcc/config/sh/lib1funcs.asm 2001/06/03 17:27:27
@@ -1217,18 +1217,23 @@ GLOBAL(ic_invalidate):
 	ocbwb	@r4
 	mova	0f,r0
 	mov.w	1f,r1
+/* Compute how many cache lines 0f is away from r4.  */
 	sub	r0,r4
 	and	r1,r4
-	add	#4,r4
+/* Prepare to branch to 0f plus the cache-line offset.  */
+	add	# 0f - 1f,r4
 	braf	r4
 	nop
 1:
 	.short	0x1fe0
-	nop
+	.p2align 5
+/* This must be aligned to the beginning of a cache line.  */
 0:
-	.rept	2048
+	.rept	256 /* There are 256 cache lines of 32 bytes.  */
 	rts
+	.rept	15
 	nop
+	.endr
 	.endr
 #endif /* SH4 */
 #endif /* L_ic_invalidate */

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                  aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist    *Please* write to mailing lists, not to me

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