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b24413180f
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
473 lines
11 KiB
ArmAsm
473 lines
11 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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.file "wm_sqrt.S"
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/*---------------------------------------------------------------------------+
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| wm_sqrt.S |
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| |
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| Fixed point arithmetic square root evaluation. |
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| |
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| Copyright (C) 1992,1993,1995,1997 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
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| Australia. E-mail billm@suburbia.net |
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| |
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| Call from C as: |
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| int wm_sqrt(FPU_REG *n, unsigned int control_word) |
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| |
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+---------------------------------------------------------------------------*/
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/*---------------------------------------------------------------------------+
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| wm_sqrt(FPU_REG *n, unsigned int control_word) |
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| returns the square root of n in n. |
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| |
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| Use Newton's method to compute the square root of a number, which must |
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| be in the range [1.0 .. 4.0), to 64 bits accuracy. |
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| Does not check the sign or tag of the argument. |
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| Sets the exponent, but not the sign or tag of the result. |
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| |
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| The guess is kept in %esi:%edi |
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+---------------------------------------------------------------------------*/
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#include "exception.h"
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#include "fpu_emu.h"
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#ifndef NON_REENTRANT_FPU
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/* Local storage on the stack: */
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#define FPU_accum_3 -4(%ebp) /* ms word */
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#define FPU_accum_2 -8(%ebp)
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#define FPU_accum_1 -12(%ebp)
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#define FPU_accum_0 -16(%ebp)
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/*
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* The de-normalised argument:
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* sq_2 sq_1 sq_0
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* b b b b b b b ... b b b b b b .... b b b b 0 0 0 ... 0
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* ^ binary point here
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*/
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#define FPU_fsqrt_arg_2 -20(%ebp) /* ms word */
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#define FPU_fsqrt_arg_1 -24(%ebp)
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#define FPU_fsqrt_arg_0 -28(%ebp) /* ls word, at most the ms bit is set */
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#else
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/* Local storage in a static area: */
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.data
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.align 4,0
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FPU_accum_3:
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.long 0 /* ms word */
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FPU_accum_2:
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.long 0
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FPU_accum_1:
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.long 0
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FPU_accum_0:
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.long 0
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/* The de-normalised argument:
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sq_2 sq_1 sq_0
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b b b b b b b ... b b b b b b .... b b b b 0 0 0 ... 0
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^ binary point here
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*/
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FPU_fsqrt_arg_2:
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.long 0 /* ms word */
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FPU_fsqrt_arg_1:
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.long 0
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FPU_fsqrt_arg_0:
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.long 0 /* ls word, at most the ms bit is set */
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#endif /* NON_REENTRANT_FPU */
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.text
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ENTRY(wm_sqrt)
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pushl %ebp
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movl %esp,%ebp
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#ifndef NON_REENTRANT_FPU
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subl $28,%esp
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#endif /* NON_REENTRANT_FPU */
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pushl %esi
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pushl %edi
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pushl %ebx
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movl PARAM1,%esi
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movl SIGH(%esi),%eax
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movl SIGL(%esi),%ecx
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xorl %edx,%edx
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/* We use a rough linear estimate for the first guess.. */
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cmpw EXP_BIAS,EXP(%esi)
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jnz sqrt_arg_ge_2
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shrl $1,%eax /* arg is in the range [1.0 .. 2.0) */
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rcrl $1,%ecx
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rcrl $1,%edx
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sqrt_arg_ge_2:
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/* From here on, n is never accessed directly again until it is
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replaced by the answer. */
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movl %eax,FPU_fsqrt_arg_2 /* ms word of n */
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movl %ecx,FPU_fsqrt_arg_1
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movl %edx,FPU_fsqrt_arg_0
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/* Make a linear first estimate */
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shrl $1,%eax
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addl $0x40000000,%eax
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movl $0xaaaaaaaa,%ecx
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mull %ecx
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shll %edx /* max result was 7fff... */
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testl $0x80000000,%edx /* but min was 3fff... */
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jnz sqrt_prelim_no_adjust
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movl $0x80000000,%edx /* round up */
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sqrt_prelim_no_adjust:
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movl %edx,%esi /* Our first guess */
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/* We have now computed (approx) (2 + x) / 3, which forms the basis
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for a few iterations of Newton's method */
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movl FPU_fsqrt_arg_2,%ecx /* ms word */
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/*
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* From our initial estimate, three iterations are enough to get us
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* to 30 bits or so. This will then allow two iterations at better
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* precision to complete the process.
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*/
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/* Compute (g + n/g)/2 at each iteration (g is the guess). */
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shrl %ecx /* Doing this first will prevent a divide */
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/* overflow later. */
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movl %ecx,%edx /* msw of the arg / 2 */
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divl %esi /* current estimate */
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shrl %esi /* divide by 2 */
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addl %eax,%esi /* the new estimate */
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movl %ecx,%edx
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divl %esi
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shrl %esi
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addl %eax,%esi
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movl %ecx,%edx
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divl %esi
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shrl %esi
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addl %eax,%esi
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/*
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* Now that an estimate accurate to about 30 bits has been obtained (in %esi),
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* we improve it to 60 bits or so.
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*
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* The strategy from now on is to compute new estimates from
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* guess := guess + (n - guess^2) / (2 * guess)
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*/
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/* First, find the square of the guess */
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movl %esi,%eax
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mull %esi
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/* guess^2 now in %edx:%eax */
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movl FPU_fsqrt_arg_1,%ecx
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subl %ecx,%eax
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movl FPU_fsqrt_arg_2,%ecx /* ms word of normalized n */
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sbbl %ecx,%edx
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jnc sqrt_stage_2_positive
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/* Subtraction gives a negative result,
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negate the result before division. */
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notl %edx
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notl %eax
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addl $1,%eax
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adcl $0,%edx
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divl %esi
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movl %eax,%ecx
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movl %edx,%eax
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divl %esi
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jmp sqrt_stage_2_finish
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sqrt_stage_2_positive:
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divl %esi
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movl %eax,%ecx
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movl %edx,%eax
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divl %esi
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notl %ecx
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notl %eax
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addl $1,%eax
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adcl $0,%ecx
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sqrt_stage_2_finish:
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sarl $1,%ecx /* divide by 2 */
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rcrl $1,%eax
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/* Form the new estimate in %esi:%edi */
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movl %eax,%edi
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addl %ecx,%esi
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jnz sqrt_stage_2_done /* result should be [1..2) */
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#ifdef PARANOID
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/* It should be possible to get here only if the arg is ffff....ffff */
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cmp $0xffffffff,FPU_fsqrt_arg_1
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jnz sqrt_stage_2_error
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#endif /* PARANOID */
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/* The best rounded result. */
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xorl %eax,%eax
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decl %eax
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movl %eax,%edi
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movl %eax,%esi
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movl $0x7fffffff,%eax
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jmp sqrt_round_result
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#ifdef PARANOID
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sqrt_stage_2_error:
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pushl EX_INTERNAL|0x213
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call EXCEPTION
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#endif /* PARANOID */
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sqrt_stage_2_done:
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/* Now the square root has been computed to better than 60 bits. */
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/* Find the square of the guess. */
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movl %edi,%eax /* ls word of guess */
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mull %edi
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movl %edx,FPU_accum_1
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movl %esi,%eax
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mull %esi
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movl %edx,FPU_accum_3
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movl %eax,FPU_accum_2
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movl %edi,%eax
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mull %esi
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addl %eax,FPU_accum_1
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adcl %edx,FPU_accum_2
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adcl $0,FPU_accum_3
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/* movl %esi,%eax */
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/* mull %edi */
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addl %eax,FPU_accum_1
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adcl %edx,FPU_accum_2
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adcl $0,FPU_accum_3
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/* guess^2 now in FPU_accum_3:FPU_accum_2:FPU_accum_1 */
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movl FPU_fsqrt_arg_0,%eax /* get normalized n */
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subl %eax,FPU_accum_1
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movl FPU_fsqrt_arg_1,%eax
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sbbl %eax,FPU_accum_2
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movl FPU_fsqrt_arg_2,%eax /* ms word of normalized n */
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sbbl %eax,FPU_accum_3
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jnc sqrt_stage_3_positive
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/* Subtraction gives a negative result,
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negate the result before division */
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notl FPU_accum_1
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notl FPU_accum_2
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notl FPU_accum_3
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addl $1,FPU_accum_1
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adcl $0,FPU_accum_2
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#ifdef PARANOID
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adcl $0,FPU_accum_3 /* This must be zero */
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jz sqrt_stage_3_no_error
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sqrt_stage_3_error:
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pushl EX_INTERNAL|0x207
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call EXCEPTION
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sqrt_stage_3_no_error:
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#endif /* PARANOID */
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movl FPU_accum_2,%edx
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movl FPU_accum_1,%eax
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divl %esi
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movl %eax,%ecx
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movl %edx,%eax
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divl %esi
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sarl $1,%ecx /* divide by 2 */
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rcrl $1,%eax
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/* prepare to round the result */
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addl %ecx,%edi
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adcl $0,%esi
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jmp sqrt_stage_3_finished
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sqrt_stage_3_positive:
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movl FPU_accum_2,%edx
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movl FPU_accum_1,%eax
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divl %esi
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movl %eax,%ecx
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movl %edx,%eax
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divl %esi
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sarl $1,%ecx /* divide by 2 */
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rcrl $1,%eax
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/* prepare to round the result */
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notl %eax /* Negate the correction term */
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notl %ecx
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addl $1,%eax
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adcl $0,%ecx /* carry here ==> correction == 0 */
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adcl $0xffffffff,%esi
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addl %ecx,%edi
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adcl $0,%esi
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sqrt_stage_3_finished:
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/*
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* The result in %esi:%edi:%esi should be good to about 90 bits here,
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* and the rounding information here does not have sufficient accuracy
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* in a few rare cases.
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*/
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cmpl $0xffffffe0,%eax
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ja sqrt_near_exact_x
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cmpl $0x00000020,%eax
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jb sqrt_near_exact
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cmpl $0x7fffffe0,%eax
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jb sqrt_round_result
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cmpl $0x80000020,%eax
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jb sqrt_get_more_precision
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sqrt_round_result:
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/* Set up for rounding operations */
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movl %eax,%edx
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movl %esi,%eax
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movl %edi,%ebx
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movl PARAM1,%edi
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movw EXP_BIAS,EXP(%edi) /* Result is in [1.0 .. 2.0) */
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jmp fpu_reg_round
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sqrt_near_exact_x:
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/* First, the estimate must be rounded up. */
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addl $1,%edi
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adcl $0,%esi
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sqrt_near_exact:
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/*
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* This is an easy case because x^1/2 is monotonic.
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* We need just find the square of our estimate, compare it
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* with the argument, and deduce whether our estimate is
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* above, below, or exact. We use the fact that the estimate
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* is known to be accurate to about 90 bits.
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*/
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movl %edi,%eax /* ls word of guess */
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mull %edi
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movl %edx,%ebx /* 2nd ls word of square */
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movl %eax,%ecx /* ls word of square */
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movl %edi,%eax
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mull %esi
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addl %eax,%ebx
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addl %eax,%ebx
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#ifdef PARANOID
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cmp $0xffffffb0,%ebx
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jb sqrt_near_exact_ok
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cmp $0x00000050,%ebx
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ja sqrt_near_exact_ok
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pushl EX_INTERNAL|0x214
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call EXCEPTION
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sqrt_near_exact_ok:
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#endif /* PARANOID */
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or %ebx,%ebx
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js sqrt_near_exact_small
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jnz sqrt_near_exact_large
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or %ebx,%edx
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jnz sqrt_near_exact_large
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/* Our estimate is exactly the right answer */
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xorl %eax,%eax
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jmp sqrt_round_result
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sqrt_near_exact_small:
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/* Our estimate is too small */
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movl $0x000000ff,%eax
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jmp sqrt_round_result
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sqrt_near_exact_large:
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/* Our estimate is too large, we need to decrement it */
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subl $1,%edi
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sbbl $0,%esi
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movl $0xffffff00,%eax
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jmp sqrt_round_result
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sqrt_get_more_precision:
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/* This case is almost the same as the above, except we start
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with an extra bit of precision in the estimate. */
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stc /* The extra bit. */
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rcll $1,%edi /* Shift the estimate left one bit */
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rcll $1,%esi
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movl %edi,%eax /* ls word of guess */
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mull %edi
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movl %edx,%ebx /* 2nd ls word of square */
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movl %eax,%ecx /* ls word of square */
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movl %edi,%eax
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mull %esi
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addl %eax,%ebx
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addl %eax,%ebx
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/* Put our estimate back to its original value */
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stc /* The ms bit. */
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rcrl $1,%esi /* Shift the estimate left one bit */
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rcrl $1,%edi
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#ifdef PARANOID
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cmp $0xffffff60,%ebx
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jb sqrt_more_prec_ok
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cmp $0x000000a0,%ebx
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ja sqrt_more_prec_ok
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pushl EX_INTERNAL|0x215
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call EXCEPTION
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sqrt_more_prec_ok:
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#endif /* PARANOID */
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or %ebx,%ebx
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js sqrt_more_prec_small
|
|
|
|
jnz sqrt_more_prec_large
|
|
|
|
or %ebx,%ecx
|
|
jnz sqrt_more_prec_large
|
|
|
|
/* Our estimate is exactly the right answer */
|
|
movl $0x80000000,%eax
|
|
jmp sqrt_round_result
|
|
|
|
sqrt_more_prec_small:
|
|
/* Our estimate is too small */
|
|
movl $0x800000ff,%eax
|
|
jmp sqrt_round_result
|
|
|
|
sqrt_more_prec_large:
|
|
/* Our estimate is too large */
|
|
movl $0x7fffff00,%eax
|
|
jmp sqrt_round_result
|
|
ENDPROC(wm_sqrt)
|