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author | Zack Weinberg <zackw@panix.com> | 2017-06-08 15:39:03 -0400 |
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committer | Zack Weinberg <zackw@panix.com> | 2017-06-08 15:39:03 -0400 |
commit | 5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch) | |
tree | 4470480d904b65cf14ca524f96f79eca818c3eaf /REORG.TODO/sysdeps/i386/fpu/s_cbrtf.S | |
parent | 199fc19d3aaaf57944ef036e15904febe877fc93 (diff) | |
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Prepare for radical source tree reorganization.zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).
Diffstat (limited to 'REORG.TODO/sysdeps/i386/fpu/s_cbrtf.S')
-rw-r--r-- | REORG.TODO/sysdeps/i386/fpu/s_cbrtf.S | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/i386/fpu/s_cbrtf.S b/REORG.TODO/sysdeps/i386/fpu/s_cbrtf.S new file mode 100644 index 0000000000..645d24372d --- /dev/null +++ b/REORG.TODO/sysdeps/i386/fpu/s_cbrtf.S @@ -0,0 +1,177 @@ +/* Compute cubic root of float value. + Copyright (C) 1997-2017 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 f3,@object +f3: .double 0.191502161678719066 + ASM_SIZE_DIRECTIVE(f3) + .type f2,@object +f2: .double 0.697570460207922770 + ASM_SIZE_DIRECTIVE(f2) + .type 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 + + .type 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) + + .type 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 + cfi_adjust_cfa_offset (4) + cfi_rel_offset (ebx, 0) + LOAD_PIC_REG (bx) +#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 + 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 8(%esp), %eax + popl %ebx + cfi_adjust_cfa_offset (-4) + cfi_restore (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) |