diff options
Diffstat (limited to 'sysdeps/i386/fpu/s_cbrtf.S')
| -rw-r--r-- | sysdeps/i386/fpu/s_cbrtf.S | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/sysdeps/i386/fpu/s_cbrtf.S b/sysdeps/i386/fpu/s_cbrtf.S new file mode 100644 index 0000000000..a14e04ed2f --- /dev/null +++ b/sysdeps/i386/fpu/s_cbrtf.S @@ -0,0 +1,178 @@ +/* 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(f3,@object) +f3: .double 0.191502161678719066 + ASM_SIZE_DIRECTIVE(f3) + ASM_TYPE_DIRECTIVE(f2,@object) +f2: .double 0.697570460207922770 + ASM_SIZE_DIRECTIVE(f2) + ASM_TYPE_DIRECTIVE(f1,@object) +f1: .double 0.492659620528969547 + ASM_SIZE_DIRECTIVE(f1) + +#define CBRT2 1.2599210498948731648 +#define ONE_CBRT2 0.793700525984099737355196796584 +#define SQR_CBRT2 1.5874010519681994748 +#define ONE_SQR_CBRT2 0.629960524947436582364439673883 + + ASM_TYPE_DIRECTIVE(factor,@object) + .align ALIGNARG(4) +factor: .double ONE_SQR_CBRT2 + .double ONE_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) op##@GOTOFF(%ebx,x,1) +#else +#define MO(op) op +#define MOX(op,x) op(x) +#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 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(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 */ + 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 + 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 +#ifdef PIC + movl 8(%esp), %eax + popl %ebx +#else + movl 4(%esp), %eax +#endif + testl %eax, %eax + fstp %st(1) + jns 4f + fchs +4: ret + + /* Return the argument. */ +1: flds 4(%esp) + ret +END(__cbrtf) +weak_alias (__cbrtf, cbrtf) |