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[PATCH] Avoid clobbering call-saved cr registers in ppc hand written assembly


Hi!

gcc says:
        cr7, cr6        (not saved or special)
        cr1             (not saved, but used for FP operations)
        cr0             (not saved, but used for arithmetic operations)
        cr4, cr3, cr2   (saved)
...
        cr5, r1, r2, ap, xer (fixed)

But apparently some *lround* routines set cr[34] registers, which are
call-saved.  This causes e.g. http://bugzilla.redhat.com/450790
>From the above I believe using cr1 and cr7 instead of cr3 and cr4 should
be ok (though the patch is untested).

2008-06-12  Jakub Jelinek  <jakub@redhat.com>

	* sysdeps/powerpc/powerpc64/fpu/s_llround.S (__llround): Avoid using
	cr[34] registers.
	* sysdeps/powerpc/powerpc64/fpu/s_llroundf.S (__llroundf): Likewise.
	* sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S (__llround): Likewise.
	* sysdeps/powerpc/powerpc32/fpu/s_lround.S (__lround): Avoid using cr3
	register.

--- libc/sysdeps/powerpc/powerpc64/fpu/s_llround.S.jj	2008-04-17 10:32:49.000000000 +0200
+++ libc/sysdeps/powerpc/powerpc64/fpu/s_llround.S	2008-06-12 20:53:40.000000000 +0200
@@ -1,5 +1,5 @@
 /* llround function.  PowerPC64 version.
-   Copyright (C) 2004, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 2004, 2006, 2007, 2008 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -52,12 +52,12 @@ ENTRY (__llround)
 	fabs	fp2,fp1		/* Get the absolute value of x.  */
 	fsub	fp12,fp10,fp10	/* Compute 0.0 into fp12.  */
 	fcmpu	cr6,fp2,fp10	/* if |x| < 0.5  */
-	fcmpu	cr4,fp2,fp9	/* if |x| >= 2^52  */
-	fcmpu	cr3,fp1,fp12	/* x is negative? x < 0.0  */
+	fcmpu	cr7,fp2,fp9	/* if |x| >= 2^52  */
+	fcmpu	cr1,fp1,fp12	/* x is negative? x < 0.0  */
 	blt-	cr6,.Lretzero	/* 0.5 > x < -0.5 so just return 0.  */
-	bge-	cr4,.Lnobias	/* 2^52 > x < -2^52 just convert with no bias.  */
+	bge-	cr7,.Lnobias	/* 2^52 > x < -2^52 just convert with no bias.  */
 	fadd	fp3,fp2,fp10	/* |x|+=0.5 bias to prepare to round.  */
-	bge	cr3,.Lconvert	/* x is positive so don't negate x.  */
+	bge	cr1,.Lconvert	/* x is positive so don't negate x.  */
 	fnabs	fp3,fp3		/* -(|x|+=0.5)  */
 .Lconvert:
 	fctidz	fp4,fp3		/* Convert to Integer double word round toward 0.  */
--- libc/sysdeps/powerpc/powerpc64/fpu/s_llroundf.S.jj	2008-04-17 10:32:49.000000000 +0200
+++ libc/sysdeps/powerpc/powerpc64/fpu/s_llroundf.S	2008-06-12 20:54:17.000000000 +0200
@@ -1,5 +1,5 @@
 /* llroundf function.  PowerPC64 version.
-   Copyright (C) 2004, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 2004, 2006, 2007, 2008 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -51,12 +51,12 @@ ENTRY (__llroundf)
 	fabs	fp2,fp1		/* Get the absolute value of x.  */
 	fsub	fp12,fp10,fp10	/* Compute 0.0 into fp12.  */
 	fcmpu	cr6,fp2,fp10	/* if |x| < 0.5  */
-	fcmpu	cr4,fp2,fp9	/* if |x| >= 2^23  */
-	fcmpu	cr3,fp1,fp12	/* x is negative? x < 0.0  */
+	fcmpu	cr7,fp2,fp9	/* if |x| >= 2^23  */
+	fcmpu	cr1,fp1,fp12	/* x is negative? x < 0.0  */
 	blt-	cr6,.Lretzero	/* 0.5 > x < -0.5 so just return 0.  */
-	bge-	cr4,.Lnobias	/* 2^23 > x < -2^23 just convert with no bias.  */
+	bge-	cr7,.Lnobias	/* 2^23 > x < -2^23 just convert with no bias.  */
 	fadd	fp3,fp2,fp10	/* |x|+=0.5 bias to prepare to round.  */
-	bge	cr3,.Lconvert	/* x is positive so don't negate x.  */
+	bge	cr1,.Lconvert	/* x is positive so don't negate x.  */
 	fnabs	fp3,fp3		/* -(|x|+=0.5)  */
 .Lconvert:
 	fctidz	fp4,fp3		/* Convert to Integer double word round toward 0.  */
--- libc/sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S.jj	2008-04-17 10:32:49.000000000 +0200
+++ libc/sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S	2008-06-12 20:54:50.000000000 +0200
@@ -1,5 +1,5 @@
 /* llround function.  PowerPC32 on PowerPC64 version.
-   Copyright (C) 2004, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 2004, 2006, 2007, 2008 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -75,12 +75,12 @@ ENTRY (__llround)
 	fabs	fp2,fp1		/* Get the absolute value of x.  */
 	fsub	fp12,fp10,fp10	/* Compute 0.0 into fpr12.  */
 	fcmpu	cr6,fp2,fp10	/* if |x| < 0.5  */
-	fcmpu	cr4,fp2,fp9	/* if |x| >= 2^52  */
-	fcmpu	cr3,fp1,fp12	/* x is negative? x < 0.0  */
+	fcmpu	cr7,fp2,fp9	/* if |x| >= 2^52  */
+	fcmpu	cr1,fp1,fp12	/* x is negative? x < 0.0  */
 	blt-	cr6,.Lretzero	/* 0.5 > x < -0.5 so just return 0.  */
-	bge-	cr4,.Lnobias	/* 2^52 > x < -2^52 just convert with no bias.  */
+	bge-	cr7,.Lnobias	/* 2^52 > x < -2^52 just convert with no bias.  */
 	fadd	fp3,fp2,fp10	/* |x|+=0.5 bias to prepare to round.  */
-	bge	cr3,.Lconvert	/* x is positive so don't negate x.  */
+	bge	cr1,.Lconvert	/* x is positive so don't negate x.  */
 	fnabs	fp3,fp3		/* -(|x|+=0.5)  */
 .Lconvert:
 	fctidz	fp4,fp3		/* Convert to Integer double word round toward 0.  */
--- libc/sysdeps/powerpc/powerpc32/fpu/s_lround.S.jj	2008-04-17 10:32:49.000000000 +0200
+++ libc/sysdeps/powerpc/powerpc32/fpu/s_lround.S	2008-06-12 20:55:16.000000000 +0200
@@ -1,5 +1,5 @@
 /* lround function.  PowerPC32 version.
-   Copyright (C) 2004, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 2004, 2006, 2007, 2008 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -65,10 +65,10 @@ ENTRY (__lround)
 	fabs	fp2, fp1	/* Get the absolute value of x.  */
 	fsub	fp12,fp10,fp10	/* Compute 0.0.  */
 	fcmpu	cr6, fp2, fp10	/* if |x| < 0.5  */
-	fcmpu	cr3, fp1, fp12	/* x is negative? x < 0.0  */
+	fcmpu	cr7, fp1, fp12	/* x is negative? x < 0.0  */
 	blt-	cr6,.Lretzero
 	fadd	fp3,fp2,fp10	/* |x|+=0.5 bias to prepare to round.  */
-	bge	cr3,.Lconvert	/* x is positive so don't negate x.  */
+	bge	cr7,.Lconvert	/* x is positive so don't negate x.  */
 	fnabs	fp3,fp3		/* -(|x|+=0.5)  */ 
 .Lconvert:
 	fctiwz	fp4,fp3		/* Convert to Integer word lround toward 0.  */


	Jakub


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