yann@966: Fix memset on PowerPC 8xx, by Nye Liu:
yann@966: http://sourceware.org/ml/crossgcc/2008-10/msg00067.html
yann@966: 
yann@966: Quote:
yann@966:  I am working on a powerpc 860 toolchain, but I am having problems  
yann@966:  convincing glibc to not emit code that uses the dcbz instruction (CPU15  
yann@966:  dcbX bug). The source of the problem is sysdeps/powerpc/power3/memset.S
yann@966: 
yann@966: --- glibc-2.7/sysdeps/powerpc/powerpc32/memset.S	2007-03-26 13:09:07.000000000 -0700
yann@1016: +++ glibc-2.7/sysdeps/powerpc/powerpc32/memset.S.new	2008-10-23 20:28:52.000000000 -0700
yann@966: @@ -112,11 +112,13 @@
yann@966:  	clrrwi.	rALIGN, rLEN, 5
yann@966:  	mtcrf	0x01, rLEN	/* 40th instruction from .align */
yann@966:  
yann@966: +#ifndef BROKEN_PPC_8xx_CPU15
yann@966:  /* Check if we can use the special case for clearing memory using dcbz.
yann@966:     This requires that we know the correct cache line size for this
yann@966:     processor.  Getting the __cache_line_size may require establishing GOT
yann@966:     addressability, so branch out of line to set this up.  */
yann@966:  	beq	cr1, L(checklinesize)
yann@966: +#endif
yann@966:  
yann@966:  /* Store blocks of 32-bytes (256-bits) starting on a 32-byte boundary.
yann@966:     Can't assume that rCHR is zero or that the cache line size is either
yann@1016: @@ -158,6 +160,7 @@
yann@1016:  	add	rMEMP, rMEMP, rALIGN
yann@1016:  	b	L(medium_tail2)	/* 72nd instruction from .align */
yann@1016:  
yann@1016: +#ifndef BROKEN_PPC_8xx_CPU15
yann@1016:  	.align	5
yann@1016:  	nop
yann@1016:  /* Clear cache lines of memory in 128-byte chunks.
yann@1016: @@ -191,6 +194,7 @@
yann@1016:  	bdnz	L(zloop)
yann@1016:  	beqlr	cr5
yann@1016:  	b	L(medium_tail2)
yann@1016: +#endif /* ! BROKEN_PPC_8xx_CPU15 */
yann@1016:  
yann@1016:  	.align	5
yann@1016:  L(small):
yann@1016: @@ -248,6 +252,7 @@
yann@966:  	stw	rCHR, -8(rMEMP)
yann@966:  	blr
yann@966:  
yann@966: +#ifndef BROKEN_PPC_8xx_CPU15
yann@966:  L(checklinesize):
yann@966:  #ifdef SHARED
yann@966:  	mflr	rTMP
yann@1016: @@ -329,6 +334,7 @@
yann@966:  L(handletail32):
yann@966:  	clrrwi.	rALIGN, rLEN, 5
yann@966:  	b	L(nondcbz)
yann@966: +#endif /* ! BROKEN_PPC_8xx_CPU15 */
yann@966:  
yann@966:  END (BP_SYM (memset))
yann@966:  libc_hidden_builtin_def (memset)