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-rw-r--r--sysdeps/powerpc/powerpc32/fpu/s_round.S118
1 files changed, 118 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/fpu/s_round.S b/sysdeps/powerpc/powerpc32/fpu/s_round.S
new file mode 100644
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--- /dev/null
+++ b/sysdeps/powerpc/powerpc32/fpu/s_round.S
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+/* round function.  PowerPC32 version.
+   Copyright (C) 2004 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
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <sysdep.h>
+
+	.section	.rodata
+	.align 3
+	.type	TWO52.0,@object
+	.size	TWO52.0,8
+TWO52.0:
+	.long 0x43300000
+	.long 0
+	.type	POINTFIVE.0,@object
+	.size	POINTFIVE.0,8
+POINTFIVE.0:
+	.long 0x3fe00000
+	.long 0
+	.type	NEGZERO.0,@object
+	.size	NEGZERO.0,8
+NEGZERO.0:
+	.long 0x80000000
+	.long 0
+
+	.section	.rodata.cst8,"aM",@progbits,8
+	.align 3
+.LC0:	/* 2**52 */
+	.long 0x43300000
+	.long 0
+.LC1:	/* 0.5 */
+	.long 0x3fe00000
+	.long 0
+.LC2:	/* -0.0 */
+	.long 0x80000000
+	.long 0
+
+/* double [fp1] round (double x [fp1])
+   IEEE 1003.1 round function.  IEEE specifies "round to the nearest 
+   integer value, rounding halfway cases away from zero, regardless of
+   the current rounding mode."  However PowerPC Architecture defines
+   "Round to Nearest" as "Choose the best approximation. In case of a 
+   tie, choose the one that is even (least significant bit o).". 
+   So we can't use the PowerPC "Round to Nearest" mode. Instead we set
+   "Round toward Zero" mode and round by adding +-0.5 before rounding
+   to the integer value.  */
+
+ENTRY (__round)
+	mffs	fp11		/* Save current FPU rounding mode.  */
+#ifdef SHARED
+	mflr	r11
+	bl	_GLOBAL_OFFSET_TABLE_@local-4
+	mflr	r10
+	lwz	r9,.LC0@got(10)
+	mtlr	r11
+	lfd	fp13,0(r9)
+#else
+	lis	r9,.LC0@ha
+	lfd	fp13,.LC0@l(r9)
+#endif
+	fabs	fp0,fp1
+	fsub	fp12,fp13,fp13	/* generate 0.0  */
+	fcmpu	cr7,fp0,fp13	/* if (fabs(x) > TWO52)  */
+	fcmpu	cr6,fp1,fp12	/* if (x > 0.0)  */
+	bnllr-	cr7
+	mtfsfi	7,1		/* Set rounding mode toward 0.  */
+#ifdef SHARED
+	lwz	r9,.LC1@got(10)
+	lfd	fp10,0(r9)
+#else
+	lis	r9,.LC1@ha
+	lfd	fp10,.LC1@l(r9)
+#endif
+	ble-	cr6,.L4
+	fadd	fp1,fp1,fp10	/* x+= 0.5;  */
+	fadd	fp1,fp1,fp13	/* x+= TWO52;  */
+	fsub	fp1,fp1,fp13	/* x-= TWO52;  */
+.L9:	
+	mtfsf	0x01,fp11	/* restore previous rounding mode.  */
+	blr
+.L4:
+	fsub	fp9,fp1,fp10	/* x+= 0.5;  */
+	bge-	cr6,.L9		/* if (x < 0.0)  */
+	fsub	fp1,fp9,fp13	/* x-= TWO52;  */
+	fadd	fp1,fp1,fp13	/* x+= TWO52;  */
+	fcmpu	cr5,fp1,fp12	/* if (x > 0.0)  */
+	mtfsf	0x01,fp11	/* restore previous rounding mode.  */
+	bnelr+	cr5
+#ifdef SHARED
+	lwz	r9,.LC2@got(10)
+	lfd	fp1,0(r9)
+#else
+	lis	r9,.LC2@ha
+	lfd	fp1,.LC2@l(r9)
+#endif
+	blr
+	END (__round)
+
+weak_alias (__round, round)
+
+#ifdef NO_LONG_DOUBLE
+weak_alias (__round, roundl)
+strong_alias (__round, __roundl)
+#endif