glibc/sysdeps/i386/fpu/s_cbrtl.S
Joseph Myers 40720ec9f9 Fix i386 cbrtl (sNaN) (bug 20224).
The i386 version of cbrtl returns sNaN (without raising any
exceptions) for sNaN input.  This patch fixes it to add non-finite
arguments to themselves (the code path in question is also reached for
zero arguments, for which adding them to themselves is also harmless),
so that "invalid" is raised and qNaN returned.

Tested for x86_64 and x86.

	[BZ #20224]
	* sysdeps/i386/fpu/s_cbrtl.S (__cbrtl): Add non-finite or zero
	argument to itself.
	* math/libm-test.inc (cbrt_test_data): Add sNaN tests.
2016-06-08 21:02:40 +00:00

230 lines
5.9 KiB
ArmAsm

/* Compute cubic root of long double value.
Copyright (C) 1997-2016 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 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
<http://www.gnu.org/licenses/>. */
#include <machine/asm.h>
.section .rodata
.align ALIGNARG(4)
.type f8,@object
f8: .tfloat 0.161617097923756032
ASM_SIZE_DIRECTIVE(f8)
.align ALIGNARG(4)
.type f7,@object
f7: .tfloat -0.988553671195413709
ASM_SIZE_DIRECTIVE(f7)
.align ALIGNARG(4)
.type f6,@object
f6: .tfloat 2.65298938441952296
ASM_SIZE_DIRECTIVE(f6)
.align ALIGNARG(4)
.type f5,@object
f5: .tfloat -4.11151425200350531
ASM_SIZE_DIRECTIVE(f5)
.align ALIGNARG(4)
.type f4,@object
f4: .tfloat 4.09559907378707839
ASM_SIZE_DIRECTIVE(f4)
.align ALIGNARG(4)
.type f3,@object
f3: .tfloat -2.82414939754975962
ASM_SIZE_DIRECTIVE(f3)
.align ALIGNARG(4)
.type f2,@object
f2: .tfloat 1.67595307700780102
ASM_SIZE_DIRECTIVE(f2)
.align ALIGNARG(4)
.type f1,@object
f1: .tfloat 0.338058687610520237
ASM_SIZE_DIRECTIVE(f1)
#define CBRT2 1.2599210498948731648
#define ONE_CBRT2 0.793700525984099737355196796584
#define SQR_CBRT2 1.5874010519681994748
#define ONE_SQR_CBRT2 0.629960524947436582364439673883
/* We make the entries in the following table all 16 bytes
wide to avoid having to implement a multiplication by 10. */
.type factor,@object
.align ALIGNARG(4)
factor: .tfloat ONE_SQR_CBRT2
.byte 0, 0, 0, 0, 0, 0
.tfloat ONE_CBRT2
.byte 0, 0, 0, 0, 0, 0
.tfloat 1.0
.byte 0, 0, 0, 0, 0, 0
.tfloat CBRT2
.byte 0, 0, 0, 0, 0, 0
.tfloat SQR_CBRT2
ASM_SIZE_DIRECTIVE(factor)
.type two64,@object
.align ALIGNARG(4)
two64: .byte 0, 0, 0, 0, 0, 0, 0xf0, 0x43
ASM_SIZE_DIRECTIVE(two64)
#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(__cbrtl)
movl 4(%esp), %ecx
movl 12(%esp), %eax
orl 8(%esp), %ecx
movl %eax, %edx
andl $0x7fff, %eax
orl %eax, %ecx
jz 1f
xorl %ecx, %ecx
cmpl $0x7fff, %eax
je 1f
#ifdef PIC
pushl %ebx
cfi_adjust_cfa_offset (4)
cfi_rel_offset (ebx, 0)
LOAD_PIC_REG (bx)
#endif
cmpl $0, %eax
jne 2f
#ifdef PIC
fldt 8(%esp)
#else
fldt 4(%esp)
#endif
fmull MO(two64)
movl $-64, %ecx
#ifdef PIC
fstpt 8(%esp)
movl 16(%esp), %eax
#else
fstpt 4(%esp)
movl 12(%esp), %eax
#endif
movl %eax, %edx
andl $0x7fff, %eax
2: andl $0x8000, %edx
subl $16382, %eax
orl $0x3ffe, %edx
addl %eax, %ecx
#ifdef PIC
movl %edx, 16(%esp)
fldt 8(%esp) /* xm */
#else
movl %edx, 12(%esp)
fldt 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. */
fldt MO(f8) /* f8 : xm */
fmul %st(1) /* f8*xm : xm */
fldt MO(f7)
faddp /* f7+f8*xm : xm */
fmul %st(1) /* (f7+f8*xm)*xm : xm */
movl $1431655766, %eax
fldt MO(f6)
faddp /* f6+(f7+f8*xm)*xm : xm */
imull %ecx
fmul %st(1) /* (f6+(f7+f8*xm)*xm)*xm : xm */
movl %ecx, %eax
fldt MO(f5)
faddp /* f5+(f6+(f7+f8*xm)*xm)*xm : xm */
sarl $31, %eax
fmul %st(1) /* (f5+(f6+(f7+f8*xm)*xm)*xm)*xm : xm */
subl %eax, %edx
fldt MO(f4)
faddp /* f4+(f5+(f6+(f7+f8*xm)*xm)*xm)*xm : xm */
fmul %st(1) /* (f4+(f5+(f6+(f7+f8*xm)*xm)*xm)*xm)*xm : xm */
fldt MO(f3)
faddp /* f3+(f4+(f5+(f6+(f7+f8*xm)*xm)*xm)*xm)*xm : xm */
fmul %st(1) /* (f3+(f4+(f5+(f6+(f7+f8*xm)*xm)*xm)*xm)*xm)*xm : xm */
fldt MO(f2)
faddp /* f2+(f3+(f4+(f5+(f6+(f7+f8*xm)*xm)*xm)*xm)*xm)*xm : xm */
fmul %st(1) /* (f2+(f3+(f4+(f5+(f6+(f7+f8*xm)*xm)*xm)*xm)*xm)*xm)*xm : xm */
fldt MO(f1)
faddp /* u:=f1+(f2+(f3+(f4+(f5+(f6+(f7+f8*xm)*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 $4, %ecx
fmulp /* u*(t2+2*xm) : 2*t2+xm */
fdivp %st, %st(1) /* u*(t2+2*xm)/(2*t2+xm) */
fldt MOX(32+factor,%ecx)
fmulp /* 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 16(%esp), %eax
popl %ebx
cfi_adjust_cfa_offset (-4)
cfi_restore (ebx)
#else
movl 12(%esp), %eax
#endif
testl $0x8000, %eax
fstp %st(1)
jz 4f
fchs
4: ret
/* Return the argument. */
1: fldt 4(%esp)
fadd %st
ret
END(__cbrtl)
weak_alias (__cbrtl, cbrtl)