Fix memset on PowerPC 8xx, by Nye Liu:
http://sourceware.org/ml/crossgcc/2008-10/msg00067.html

Quote:
 I am working on a powerpc 860 toolchain, but I am having problems  
 convincing glibc to not emit code that uses the dcbz instruction (CPU15  
 dcbX bug). The source of the problem is sysdeps/powerpc/power3/memset.S

--- glibc-2.7/sysdeps/powerpc/powerpc32/memset.S	2007-03-26 13:09:07.000000000 -0700
+++ glibc-2.7/sysdeps/powerpc/powerpc32/memset.S.new	2008-10-23 20:28:52.000000000 -0700
@@ -112,11 +112,13 @@
 	clrrwi.	rALIGN, rLEN, 5
 	mtcrf	0x01, rLEN	/* 40th instruction from .align */
 
+#ifndef BROKEN_PPC_8xx_CPU15
 /* Check if we can use the special case for clearing memory using dcbz.
    This requires that we know the correct cache line size for this
    processor.  Getting the __cache_line_size may require establishing GOT
    addressability, so branch out of line to set this up.  */
 	beq	cr1, L(checklinesize)
+#endif
 
 /* Store blocks of 32-bytes (256-bits) starting on a 32-byte boundary.
    Can't assume that rCHR is zero or that the cache line size is either
@@ -158,6 +160,7 @@
 	add	rMEMP, rMEMP, rALIGN
 	b	L(medium_tail2)	/* 72nd instruction from .align */
 
+#ifndef BROKEN_PPC_8xx_CPU15
 	.align	5
 	nop
 /* Clear cache lines of memory in 128-byte chunks.
@@ -191,6 +194,7 @@
 	bdnz	L(zloop)
 	beqlr	cr5
 	b	L(medium_tail2)
+#endif /* ! BROKEN_PPC_8xx_CPU15 */
 
 	.align	5
 L(small):
@@ -248,6 +252,7 @@
 	stw	rCHR, -8(rMEMP)
 	blr
 
+#ifndef BROKEN_PPC_8xx_CPU15
 L(checklinesize):
 #ifdef SHARED
 	mflr	rTMP
@@ -329,6 +334,7 @@
 L(handletail32):
 	clrrwi.	rALIGN, rLEN, 5
 	b	L(nondcbz)
+#endif /* ! BROKEN_PPC_8xx_CPU15 */
 
 END (BP_SYM (memset))
 libc_hidden_builtin_def (memset)