glibc/sysdeps/i386/fpu/s_cbrt.S
Siddhesh Poyarekar 30891f35fa Remove "Contributed by" lines
We stopped adding "Contributed by" or similar lines in sources in 2012
in favour of git logs and keeping the Contributors section of the
glibc manual up to date.  Removing these lines makes the license
header a bit more consistent across files and also removes the
possibility of error in attribution when license blocks or files are
copied across since the contributed-by lines don't actually reflect
reality in those cases.

Move all "Contributed by" and similar lines (Written by, Test by,
etc.) into a new file CONTRIBUTED-BY to retain record of these
contributions.  These contributors are also mentioned in
manual/contrib.texi, so we just maintain this additional record as a
courtesy to the earlier developers.

The following scripts were used to filter a list of files to edit in
place and to clean up the CONTRIBUTED-BY file respectively.  These
were not added to the glibc sources because they're not expected to be
of any use in future given that this is a one time task:

https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc
https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-09-03 22:06:44 +05:30

200 lines
5.0 KiB
ArmAsm

/* Compute cubic root of double value.
Copyright (C) 1997-2021 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, see
<https://www.gnu.org/licenses/>. */
#include <machine/asm.h>
#include <libm-alias-double.h>
.section .rodata
.align ALIGNARG(4)
.type f7,@object
f7: .double -0.145263899385486377
ASM_SIZE_DIRECTIVE(f7)
.type f6,@object
f6: .double 0.784932344976639262
ASM_SIZE_DIRECTIVE(f6)
.type f5,@object
f5: .double -1.83469277483613086
ASM_SIZE_DIRECTIVE(f5)
.type f4,@object
f4: .double 2.44693122563534430
ASM_SIZE_DIRECTIVE(f4)
.type f3,@object
f3: .double -2.11499494167371287
ASM_SIZE_DIRECTIVE(f3)
.type f2,@object
f2: .double 1.50819193781584896
ASM_SIZE_DIRECTIVE(f2)
.type f1,@object
f1: .double 0.354895765043919860
ASM_SIZE_DIRECTIVE(f1)
#define CBRT2 1.2599210498948731648
#define ONE_CBRT2 0.793700525984099737355196796584
#define SQR_CBRT2 1.5874010519681994748
#define ONE_SQR_CBRT2 0.629960524947436582364439673883
.type factor,@object
factor: .double ONE_SQR_CBRT2
.double ONE_CBRT2
.double 1.0
.double CBRT2
.double SQR_CBRT2
ASM_SIZE_DIRECTIVE(factor)
.type two54,@object
two54: .byte 0, 0, 0, 0, 0, 0, 0x50, 0x43
ASM_SIZE_DIRECTIVE(two54)
#ifdef PIC
#define MO(op) op##@GOTOFF(%ebx)
#define MOX(op,x) op##@GOTOFF(%ebx,x,1)
#else
#define MO(op) op
#define MOX(op,x) op(x)
#endif
.text
ENTRY(__cbrt)
movl 4(%esp), %ecx
movl 8(%esp), %eax
movl %eax, %edx
andl $0x7fffffff, %eax
orl %eax, %ecx
jz 1f
xorl %ecx, %ecx
cmpl $0x7ff00000, %eax
jae 1f
#ifdef PIC
pushl %ebx
cfi_adjust_cfa_offset (4)
cfi_rel_offset (ebx, 0)
LOAD_PIC_REG (bx)
#endif
cmpl $0x00100000, %eax
jae 2f
#ifdef PIC
fldl 8(%esp)
#else
fldl 4(%esp)
#endif
fmull MO(two54)
movl $-54, %ecx
#ifdef PIC
fstpl 8(%esp)
movl 12(%esp), %eax
#else
fstpl 4(%esp)
movl 8(%esp), %eax
#endif
movl %eax, %edx
andl $0x7fffffff, %eax
2: shrl $20, %eax
andl $0x800fffff, %edx
subl $1022, %eax
orl $0x3fe00000, %edx
addl %eax, %ecx
#ifdef PIC
movl %edx, 12(%esp)
fldl 8(%esp) /* xm */
#else
movl %edx, 8(%esp)
fldl 4(%esp) /* xm */
#endif
fabs
/* The following code has two tracks:
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.
But why two tracks at all? Very easy: efficiency. Some FP
instruction can overlap with a certain amount of integer (and
FP) instructions. So we get (except for the imull) all
instructions for free. */
fld %st(0) /* xm : xm */
fmull MO(f7) /* f7*xm : xm */
movl $1431655766, %eax
faddl MO(f6) /* f6+f7*xm : xm */
imull %ecx
fmul %st(1) /* (f6+f7*xm)*xm : xm */
movl %ecx, %eax
faddl MO(f5) /* f5+(f6+f7*xm)*xm : xm */
sarl $31, %eax
fmul %st(1) /* (f5+(f6+f7*xm)*xm)*xm : xm */
subl %eax, %edx
faddl MO(f4) /* f4+(f5+(f6+f7*xm)*xm)*xm : xm */
fmul %st(1) /* (f4+(f5+(f6+f7*xm)*xm)*xm)*xm : xm */
faddl MO(f3) /* f3+(f4+(f5+(f6+f7*xm)*xm)*xm)*xm : xm */
fmul %st(1) /* (f3+(f4+(f5+(f6+f7*xm)*xm)*xm)*xm)*xm : xm */
faddl MO(f2) /* f2+(f3+(f4+(f5+(f6+f7*xm)*xm)*xm)*xm)*xm : xm */
fmul %st(1) /* (f2+(f3+(f4+(f5+(f6+f7*xm)*xm)*xm)*xm)*xm)*xm : xm */
faddl MO(f1) /* u:=f1+(f2+(f3+(f4+(f5+(f6+f7*xm)*xm)*xm)*xm)*xm)*xm : xm */
fld %st /* u : u : xm */
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 */
shll $3, %ecx
fmulp /* u*(t2+2*xm) : 2*t2+xm */
fdivp %st, %st(1) /* u*(t2+2*xm)/(2*t2+xm) */
fmull MOX(16+factor,%ecx) /* u*(t2+2*xm)/(2*t2+xm)*FACT */
pushl %eax
cfi_adjust_cfa_offset (4)
fildl (%esp) /* xe/3 : u*(t2+2*xm)/(2*t2+xm)*FACT */
fxch /* u*(t2+2*xm)/(2*t2+xm)*FACT : xe/3 */
fscale /* u*(t2+2*xm)/(2*t2+xm)*FACT*2^xe/3 */
popl %edx
cfi_adjust_cfa_offset (-4)
#ifdef PIC
movl 12(%esp), %eax
popl %ebx
cfi_adjust_cfa_offset (-4)
cfi_restore (ebx)
#else
movl 8(%esp), %eax
#endif
testl %eax, %eax
fstp %st(1)
jns 4f
fchs
4: ret
/* Return the argument. */
1: fldl 4(%esp)
ret
END(__cbrt)
libm_alias_double (__cbrt, cbrt)