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-rw-r--r--sysdeps/libm-i387/s_cbrtf.S166
1 files changed, 166 insertions, 0 deletions
diff --git a/sysdeps/libm-i387/s_cbrtf.S b/sysdeps/libm-i387/s_cbrtf.S
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+/* Compute cubic root of float value.
+ Copyright (C) 1997 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Dirk Alboth <dirka@uni-paderborn.de> and
+ Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 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
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <machine/asm.h>
+
+#ifdef __ELF__
+ .section .rodata
+#else
+ .text
+#endif
+
+ .align ALIGNARG(4)
+ ASM_TYPE_DIRECTIVE(f1,@object)
+f1: .double 0.492659620528969547
+ ASM_SIZE_DIRECTIVE(f1)
+ ASM_TYPE_DIRECTIVE(f2,@object)
+f2: .double 0.697570460207922770
+ ASM_SIZE_DIRECTIVE(f2)
+ ASM_TYPE_DIRECTIVE(f3,@object)
+f3: .double 0.191502161678719066
+ ASM_SIZE_DIRECTIVE(f3)
+
+#define CBRT2 1.2599210498948731648
+#define SQR_CBRT2 1.5874010519681994748
+
+ ASM_TYPE_DIRECTIVE(factor,@object)
+factor: .double 1.0 / SQR_CBRT2
+ .double 1.0 / CBRT2
+ .double 1.0
+ .double CBRT2
+ .double SQR_CBRT2
+ ASM_SIZE_DIRECTIVE(factor)
+
+ ASM_TYPE_DIRECTIVE(two25,@object)
+two25: .byte 0, 0, 0, 0x4c
+ ASM_SIZE_DIRECTIVE(two25)
+
+#ifdef PIC
+#define MO(op) op##@GOTOFF(%ebx)
+#define MOX(op,x,f) op##@GOTOFF(%ebx,x,f)
+#else
+#define MO(op) op
+#define MOX(op,x,f) op(,x,f)
+#endif
+
+ .text
+ENTRY(__cbrtf)
+ movl 4(%esp), %eax
+ xorl %ecx, %ecx
+ movl %eax, %edx
+ andl $0x7fffffff, %eax
+ jz 1f
+ cmpl $0x7f800000, %eax
+ jae 1f
+
+#ifdef PIC
+ pushl %ebx
+ call 3f
+3: popl %ebx
+ addl $_GLOBAL_OFFSET_TABLE_+[.-3b], %ebx
+#endif
+
+ cmpl $0x00800000, %eax
+ jae 2f
+
+#ifdef PIC
+ flds 8(%esp)
+#else
+ flds 4(%esp)
+#endif
+ fmuls MO(two25)
+ movl $-25, %ecx
+#ifdef PIC
+ fstps 8(%esp)
+ movl 8(%esp), %eax
+#else
+ fstps 4(%esp)
+ movl 4(%esp), %eax
+#endif
+ movl %eax, %edx
+ andl $0x7fffffff, %eax
+
+2: shrl $23, %eax
+ andl $0x807fffff, %edx
+ subl $126, %eax
+ orl $0x3f000000, %edx
+ addl %eax, %ecx
+#ifdef PIC
+ movl %edx, 8(%esp)
+
+ flds 8(%esp) /* xm */
+#else
+ movl %edx, 4(%esp)
+
+ flds 4(%esp) /* xm */
+#endif
+ fabs
+
+ /* The following code has two track:
+ a) compute the normalized cbrt value
+ b) compute xe/3 and xe%3
+ The right track computes the value for b) and this is done
+ in an optimized way by avoiding division. */
+
+ fld %st(0) /* xm : xm */
+ fmull MO(f3) /* f3*xm : xm */
+ movl $1431655766, %eax
+ fsubrl MO(f2) /* f2-f3*xm : xm */
+ imull %ecx
+ fmul %st(1) /* (f2-f3*xm)*xm : xm */
+ movl %ecx, %eax
+ faddl MO(f1) /* u:=f1+(f2-f3*xm)*xm : xm */
+ sarl $31, %eax
+ fld %st /* u : u : xm */
+ subl %eax, %edx
+ fmul %st(1) /* u*u : u : xm */
+ fld %st(2) /* xm : u*u : u : xm */
+ fadd %st /* 2*xm : u*u : u : xm */
+ fxch %st(1) /* u*u : 2*xm : u : xm */
+ fmul %st(2) /* t2:=u*u*u : 2*xm : u : xm */
+ movl %edx, %eax
+ fadd %st, %st(1) /* t2 : t2+2*xm : u : xm */
+ leal (%edx,%edx,2),%edx
+ fadd %st(0) /* 2*t2 : t2+2*xm : u : xm */
+ subl %edx, %ecx
+ faddp %st, %st(3) /* t2+2*xm : u : 2*t2+xm */
+ fmulp /* u*(t2+2*xm) : 2*t2+xm */
+ fdivp %st, %st(1) /* u*(t2+2*xm)/(2*t2+xm) */
+ fmull MOX(16+factor,%ecx,8) /* u*(t2+2*xm)/(2*t2+xm)*FACT */
+ pushl %eax
+ fildl (%esp) /* xe/3 : u*(t2+2*xm)/(2*t2+xm)*FACT */
+ fxch /* u*(t2+2*xm)/(2*t2+xm)*FACT : xe/3 */
+ popl %eax
+ fscale /* u*(t2+2*xm)/(2*t2+xm)*FACT*2^xe/3 */
+ fstp %st(1)
+#ifdef PIC
+ popl %ebx
+#endif
+ testl $0x80000000, 4(%esp)
+ jz 4f
+ fchs
+4: ret
+
+ /* Return the argument. */
+1: flds 4(%esp)
+ ret
+END(__cbrtf)
+weak_alias (__cbrtf, cbrtf)