make: fix builds with clang by embedding required compiler-rt functions
This commit is contained in:
parent
1c96d1dfae
commit
88363fa19e
10
Makefile
10
Makefile
@ -70,9 +70,13 @@ RAMDISK_FILES= ${APPS_X} ${APPS_SH_X} ${LIBS_X} base/lib/ld.so base/lib/libm.so
|
||||
ifeq (,${USE_CLANG})
|
||||
KCC = $(TARGET_TRIPLET)-gcc
|
||||
LGCC = -lgcc
|
||||
EXTRALIB =
|
||||
else
|
||||
KCC = clang --target=i686-elf -static -Ibase/usr/include -nostdinc -mno-sse
|
||||
LGCC = -lgcc
|
||||
LGCC = util/compiler-rt.o
|
||||
EXTRALIB = util/compiler-rt.o
|
||||
util/compiler-rt.o: util/compiler-rt.S
|
||||
${KAS} ${ASFLAGS} $< -o $@
|
||||
endif
|
||||
KAS = $(TARGET_TRIPLET)-as
|
||||
KLD = $(TARGET_TRIPLET)-ld
|
||||
@ -98,7 +102,7 @@ KERNEL_ASMOBJS = $(filter-out kernel/symbols.o,$(patsubst %.S,%.o,$(wildcard ker
|
||||
|
||||
# Kernel
|
||||
|
||||
fatbase/kernel: ${KERNEL_ASMOBJS} ${KERNEL_OBJS} kernel/symbols.o
|
||||
fatbase/kernel: ${KERNEL_ASMOBJS} ${KERNEL_OBJS} kernel/symbols.o ${EXTRALIB}
|
||||
${KCC} -T kernel/link.ld ${KCFLAGS} -nostdlib -o $@ ${KERNEL_ASMOBJS} ${KERNEL_OBJS} kernel/symbols.o ${LGCC}
|
||||
|
||||
##
|
||||
@ -109,7 +113,7 @@ fatbase/kernel: ${KERNEL_ASMOBJS} ${KERNEL_OBJS} kernel/symbols.o
|
||||
# build the kernel as a flat binary or load it with less-capable
|
||||
# multiboot loaders and still get symbols, which we need to
|
||||
# load kernel modules and link them properly.
|
||||
kernel/symbols.o: ${KERNEL_ASMOBJS} ${KERNEL_OBJS} util/generate_symbols.py
|
||||
kernel/symbols.o: ${KERNEL_ASMOBJS} ${KERNEL_OBJS} util/generate_symbols.py ${EXTRALIB}
|
||||
-rm -f kernel/symbols.o
|
||||
${KCC} -T kernel/link.ld ${KCFLAGS} -nostdlib -o .toaruos-kernel ${KERNEL_ASMOBJS} ${KERNEL_OBJS} ${LGCC}
|
||||
${KNM} .toaruos-kernel -g | util/generate_symbols.py > kernel/symbols.S
|
||||
|
517
util/compiler-rt.S
Normal file
517
util/compiler-rt.S
Normal file
@ -0,0 +1,517 @@
|
||||
// This file contains assembly implementations of:
|
||||
// __udivdi3
|
||||
// __umoddi3
|
||||
// ... from LLVM's compiler-rt, for use with building
|
||||
// the ToaruOS kernel with a bare clang, with no need to link
|
||||
// to libgcc or compiler-rt directly. If more function
|
||||
// implementations are needed in the future, these should also
|
||||
// be included here.
|
||||
|
||||
// ==============================================================================
|
||||
// The LLVM Project is under the Apache License v2.0 with LLVM Exceptions:
|
||||
// ==============================================================================
|
||||
//
|
||||
// Apache License
|
||||
// Version 2.0, January 2004
|
||||
// http://www.apache.org/licenses/
|
||||
//
|
||||
// TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
|
||||
//
|
||||
// 1. Definitions.
|
||||
//
|
||||
// "License" shall mean the terms and conditions for use, reproduction,
|
||||
// and distribution as defined by Sections 1 through 9 of this document.
|
||||
//
|
||||
// "Licensor" shall mean the copyright owner or entity authorized by
|
||||
// the copyright owner that is granting the License.
|
||||
//
|
||||
// "Legal Entity" shall mean the union of the acting entity and all
|
||||
// other entities that control, are controlled by, or are under common
|
||||
// control with that entity. For the purposes of this definition,
|
||||
// "control" means (i) the power, direct or indirect, to cause the
|
||||
// direction or management of such entity, whether by contract or
|
||||
// otherwise, or (ii) ownership of fifty percent (50%) or more of the
|
||||
// outstanding shares, or (iii) beneficial ownership of such entity.
|
||||
//
|
||||
// "You" (or "Your") shall mean an individual or Legal Entity
|
||||
// exercising permissions granted by this License.
|
||||
//
|
||||
// "Source" form shall mean the preferred form for making modifications,
|
||||
// including but not limited to software source code, documentation
|
||||
// source, and configuration files.
|
||||
//
|
||||
// "Object" form shall mean any form resulting from mechanical
|
||||
// transformation or translation of a Source form, including but
|
||||
// not limited to compiled object code, generated documentation,
|
||||
// and conversions to other media types.
|
||||
//
|
||||
// "Work" shall mean the work of authorship, whether in Source or
|
||||
// Object form, made available under the License, as indicated by a
|
||||
// copyright notice that is included in or attached to the work
|
||||
// (an example is provided in the Appendix below).
|
||||
//
|
||||
// "Derivative Works" shall mean any work, whether in Source or Object
|
||||
// form, that is based on (or derived from) the Work and for which the
|
||||
// editorial revisions, annotations, elaborations, or other modifications
|
||||
// represent, as a whole, an original work of authorship. For the purposes
|
||||
// of this License, Derivative Works shall not include works that remain
|
||||
// separable from, or merely link (or bind by name) to the interfaces of,
|
||||
// the Work and Derivative Works thereof.
|
||||
//
|
||||
// "Contribution" shall mean any work of authorship, including
|
||||
// the original version of the Work and any modifications or additions
|
||||
// to that Work or Derivative Works thereof, that is intentionally
|
||||
// submitted to Licensor for inclusion in the Work by the copyright owner
|
||||
// or by an individual or Legal Entity authorized to submit on behalf of
|
||||
// the copyright owner. For the purposes of this definition, "submitted"
|
||||
// means any form of electronic, verbal, or written communication sent
|
||||
// to the Licensor or its representatives, including but not limited to
|
||||
// communication on electronic mailing lists, source code control systems,
|
||||
// and issue tracking systems that are managed by, or on behalf of, the
|
||||
// Licensor for the purpose of discussing and improving the Work, but
|
||||
// excluding communication that is conspicuously marked or otherwise
|
||||
// designated in writing by the copyright owner as "Not a Contribution."
|
||||
//
|
||||
// "Contributor" shall mean Licensor and any individual or Legal Entity
|
||||
// on behalf of whom a Contribution has been received by Licensor and
|
||||
// subsequently incorporated within the Work.
|
||||
//
|
||||
// 2. Grant of Copyright License. Subject to the terms and conditions of
|
||||
// this License, each Contributor hereby grants to You a perpetual,
|
||||
// worldwide, non-exclusive, no-charge, royalty-free, irrevocable
|
||||
// copyright license to reproduce, prepare Derivative Works of,
|
||||
// publicly display, publicly perform, sublicense, and distribute the
|
||||
// Work and such Derivative Works in Source or Object form.
|
||||
//
|
||||
// 3. Grant of Patent License. Subject to the terms and conditions of
|
||||
// this License, each Contributor hereby grants to You a perpetual,
|
||||
// worldwide, non-exclusive, no-charge, royalty-free, irrevocable
|
||||
// (except as stated in this section) patent license to make, have made,
|
||||
// use, offer to sell, sell, import, and otherwise transfer the Work,
|
||||
// where such license applies only to those patent claims licensable
|
||||
// by such Contributor that are necessarily infringed by their
|
||||
// Contribution(s) alone or by combination of their Contribution(s)
|
||||
// with the Work to which such Contribution(s) was submitted. If You
|
||||
// institute patent litigation against any entity (including a
|
||||
// cross-claim or counterclaim in a lawsuit) alleging that the Work
|
||||
// or a Contribution incorporated within the Work constitutes direct
|
||||
// or contributory patent infringement, then any patent licenses
|
||||
// granted to You under this License for that Work shall terminate
|
||||
// as of the date such litigation is filed.
|
||||
//
|
||||
// 4. Redistribution. You may reproduce and distribute copies of the
|
||||
// Work or Derivative Works thereof in any medium, with or without
|
||||
// modifications, and in Source or Object form, provided that You
|
||||
// meet the following conditions:
|
||||
//
|
||||
// (a) You must give any other recipients of the Work or
|
||||
// Derivative Works a copy of this License; and
|
||||
//
|
||||
// (b) You must cause any modified files to carry prominent notices
|
||||
// stating that You changed the files; and
|
||||
//
|
||||
// (c) You must retain, in the Source form of any Derivative Works
|
||||
// that You distribute, all copyright, patent, trademark, and
|
||||
// attribution notices from the Source form of the Work,
|
||||
// excluding those notices that do not pertain to any part of
|
||||
// the Derivative Works; and
|
||||
//
|
||||
// (d) If the Work includes a "NOTICE" text file as part of its
|
||||
// distribution, then any Derivative Works that You distribute must
|
||||
// include a readable copy of the attribution notices contained
|
||||
// within such NOTICE file, excluding those notices that do not
|
||||
// pertain to any part of the Derivative Works, in at least one
|
||||
// of the following places: within a NOTICE text file distributed
|
||||
// as part of the Derivative Works; within the Source form or
|
||||
// documentation, if provided along with the Derivative Works; or,
|
||||
// within a display generated by the Derivative Works, if and
|
||||
// wherever such third-party notices normally appear. The contents
|
||||
// of the NOTICE file are for informational purposes only and
|
||||
// do not modify the License. You may add Your own attribution
|
||||
// notices within Derivative Works that You distribute, alongside
|
||||
// or as an addendum to the NOTICE text from the Work, provided
|
||||
// that such additional attribution notices cannot be construed
|
||||
// as modifying the License.
|
||||
//
|
||||
// You may add Your own copyright statement to Your modifications and
|
||||
// may provide additional or different license terms and conditions
|
||||
// for use, reproduction, or distribution of Your modifications, or
|
||||
// for any such Derivative Works as a whole, provided Your use,
|
||||
// reproduction, and distribution of the Work otherwise complies with
|
||||
// the conditions stated in this License.
|
||||
//
|
||||
// 5. Submission of Contributions. Unless You explicitly state otherwise,
|
||||
// any Contribution intentionally submitted for inclusion in the Work
|
||||
// by You to the Licensor shall be under the terms and conditions of
|
||||
// this License, without any additional terms or conditions.
|
||||
// Notwithstanding the above, nothing herein shall supersede or modify
|
||||
// the terms of any separate license agreement you may have executed
|
||||
// with Licensor regarding such Contributions.
|
||||
//
|
||||
// 6. Trademarks. This License does not grant permission to use the trade
|
||||
// names, trademarks, service marks, or product names of the Licensor,
|
||||
// except as required for reasonable and customary use in describing the
|
||||
// origin of the Work and reproducing the content of the NOTICE file.
|
||||
//
|
||||
// 7. Disclaimer of Warranty. Unless required by applicable law or
|
||||
// agreed to in writing, Licensor provides the Work (and each
|
||||
// Contributor provides its Contributions) on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
|
||||
// implied, including, without limitation, any warranties or conditions
|
||||
// of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
|
||||
// PARTICULAR PURPOSE. You are solely responsible for determining the
|
||||
// appropriateness of using or redistributing the Work and assume any
|
||||
// risks associated with Your exercise of permissions under this License.
|
||||
//
|
||||
// 8. Limitation of Liability. In no event and under no legal theory,
|
||||
// whether in tort (including negligence), contract, or otherwise,
|
||||
// unless required by applicable law (such as deliberate and grossly
|
||||
// negligent acts) or agreed to in writing, shall any Contributor be
|
||||
// liable to You for damages, including any direct, indirect, special,
|
||||
// incidental, or consequential damages of any character arising as a
|
||||
// result of this License or out of the use or inability to use the
|
||||
// Work (including but not limited to damages for loss of goodwill,
|
||||
// work stoppage, computer failure or malfunction, or any and all
|
||||
// other commercial damages or losses), even if such Contributor
|
||||
// has been advised of the possibility of such damages.
|
||||
//
|
||||
// 9. Accepting Warranty or Additional Liability. While redistributing
|
||||
// the Work or Derivative Works thereof, You may choose to offer,
|
||||
// and charge a fee for, acceptance of support, warranty, indemnity,
|
||||
// or other liability obligations and/or rights consistent with this
|
||||
// License. However, in accepting such obligations, You may act only
|
||||
// on Your own behalf and on Your sole responsibility, not on behalf
|
||||
// of any other Contributor, and only if You agree to indemnify,
|
||||
// defend, and hold each Contributor harmless for any liability
|
||||
// incurred by, or claims asserted against, such Contributor by reason
|
||||
// of your accepting any such warranty or additional liability.
|
||||
//
|
||||
// END OF TERMS AND CONDITIONS
|
||||
//
|
||||
// APPENDIX: How to apply the Apache License to your work.
|
||||
//
|
||||
// To apply the Apache License to your work, attach the following
|
||||
// boilerplate notice, with the fields enclosed by brackets "[]"
|
||||
// replaced with your own identifying information. (Don't include
|
||||
// the brackets!) The text should be enclosed in the appropriate
|
||||
// comment syntax for the file format. We also recommend that a
|
||||
// file or class name and description of purpose be included on the
|
||||
// same "printed page" as the copyright notice for easier
|
||||
// identification within third-party archives.
|
||||
//
|
||||
// Copyright [yyyy] [name of copyright owner]
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 (the "License");
|
||||
// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
//
|
||||
// http://www.apache.org/licenses/LICENSE-2.0
|
||||
//
|
||||
// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
//
|
||||
//
|
||||
// ---- LLVM Exceptions to the Apache 2.0 License ----
|
||||
//
|
||||
// As an exception, if, as a result of your compiling your source code, portions
|
||||
// of this Software are embedded into an Object form of such source code, you
|
||||
// may redistribute such embedded portions in such Object form without complying
|
||||
// with the conditions of Sections 4(a), 4(b) and 4(d) of the License.
|
||||
//
|
||||
// In addition, if you combine or link compiled forms of this Software with
|
||||
// software that is licensed under the GPLv2 ("Combined Software") and if a
|
||||
// court of competent jurisdiction determines that the patent provision (Section
|
||||
// 3), the indemnity provision (Section 9) or other Section of the License
|
||||
// conflicts with the conditions of the GPLv2, you may retroactively and
|
||||
// prospectively choose to deem waived or otherwise exclude such Section(s) of
|
||||
// the License, but only in their entirety and only with respect to the Combined
|
||||
// Software.
|
||||
//
|
||||
// ==============================================================================
|
||||
// Software from third parties included in the LLVM Project:
|
||||
// ==============================================================================
|
||||
// The LLVM Project contains third party software which is under different license
|
||||
// terms. All such code will be identified clearly using at least one of two
|
||||
// mechanisms:
|
||||
// 1) It will be in a separate directory tree with its own `LICENSE.txt` or
|
||||
// `LICENSE` file at the top containing the specific license and restrictions
|
||||
// which apply to that software, or
|
||||
// 2) It will contain specific license and restriction terms at the top of every
|
||||
// file.
|
||||
//
|
||||
// ==============================================================================
|
||||
// Legacy LLVM License (https://llvm.org/docs/DeveloperPolicy.html#legacy):
|
||||
// ==============================================================================
|
||||
//
|
||||
// The compiler_rt library is dual licensed under both the University of Illinois
|
||||
// "BSD-Like" license and the MIT license. As a user of this code you may choose
|
||||
// to use it under either license. As a contributor, you agree to allow your code
|
||||
// to be used under both.
|
||||
//
|
||||
// Full text of the relevant licenses is included below.
|
||||
//
|
||||
// ==============================================================================
|
||||
//
|
||||
// University of Illinois/NCSA
|
||||
// Open Source License
|
||||
//
|
||||
// Copyright (c) 2009-2019 by the contributors listed in CREDITS.TXT
|
||||
//
|
||||
// All rights reserved.
|
||||
//
|
||||
// Developed by:
|
||||
//
|
||||
// LLVM Team
|
||||
//
|
||||
// University of Illinois at Urbana-Champaign
|
||||
//
|
||||
// http://llvm.org
|
||||
//
|
||||
// Permission is hereby granted, free of charge, to any person obtaining a copy of
|
||||
// this software and associated documentation files (the "Software"), to deal with
|
||||
// the Software without restriction, including without limitation the rights to
|
||||
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
|
||||
// of the Software, and to permit persons to whom the Software is furnished to do
|
||||
// so, subject to the following conditions:
|
||||
//
|
||||
// * Redistributions of source code must retain the above copyright notice,
|
||||
// this list of conditions and the following disclaimers.
|
||||
//
|
||||
// * Redistributions in binary form must reproduce the above copyright notice,
|
||||
// this list of conditions and the following disclaimers in the
|
||||
// documentation and/or other materials provided with the distribution.
|
||||
//
|
||||
// * Neither the names of the LLVM Team, University of Illinois at
|
||||
// Urbana-Champaign, nor the names of its contributors may be used to
|
||||
// endorse or promote products derived from this Software without specific
|
||||
// prior written permission.
|
||||
//
|
||||
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
||||
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
|
||||
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
||||
// CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
||||
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
|
||||
// SOFTWARE.
|
||||
//
|
||||
// ==============================================================================
|
||||
//
|
||||
// Copyright (c) 2009-2015 by the contributors listed in CREDITS.TXT
|
||||
//
|
||||
// Permission is hereby granted, free of charge, to any person obtaining a copy
|
||||
// of this software and associated documentation files (the "Software"), to deal
|
||||
// in the Software without restriction, including without limitation the rights
|
||||
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
||||
// copies of the Software, and to permit persons to whom the Software is
|
||||
// furnished to do so, subject to the following conditions:
|
||||
//
|
||||
// The above copyright notice and this permission notice shall be included in
|
||||
// all copies or substantial portions of the Software.
|
||||
//
|
||||
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
||||
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
||||
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
||||
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
||||
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
||||
// THE SOFTWARE.
|
||||
.text
|
||||
.balign 4
|
||||
.globl __udivdi3
|
||||
__udivdi3:
|
||||
|
||||
pushl %ebx
|
||||
movl 20(%esp), %ebx // Find the index i of the leading bit in b.
|
||||
bsrl %ebx, %ecx // If the high word of b is zero, jump to
|
||||
jz 9f // the code to handle that special case [9].
|
||||
|
||||
// High word of b is known to be non-zero on this branch
|
||||
|
||||
movl 16(%esp), %eax // Construct bhi, containing bits [1+i:32+i] of b
|
||||
|
||||
shrl %cl, %eax // Practically, this means that bhi is given by:
|
||||
shrl %eax //
|
||||
notl %ecx // bhi = (high word of b) << (31 - i) |
|
||||
shll %cl, %ebx // (low word of b) >> (1 + i)
|
||||
orl %eax, %ebx //
|
||||
movl 12(%esp), %edx // Load the high and low words of a, and jump
|
||||
movl 8(%esp), %eax // to [1] if the high word is larger than bhi
|
||||
cmpl %ebx, %edx // to avoid overflowing the upcoming divide.
|
||||
jae 1f
|
||||
|
||||
// High word of a is greater than or equal to (b >> (1 + i)) on this branch
|
||||
|
||||
divl %ebx // eax <-- qs, edx <-- r such that ahi:alo = bs*qs + r
|
||||
|
||||
pushl %edi
|
||||
notl %ecx
|
||||
shrl %eax
|
||||
shrl %cl, %eax // q = qs >> (1 + i)
|
||||
movl %eax, %edi
|
||||
mull 20(%esp) // q*blo
|
||||
movl 12(%esp), %ebx
|
||||
movl 16(%esp), %ecx // ECX:EBX = a
|
||||
subl %eax, %ebx
|
||||
sbbl %edx, %ecx // ECX:EBX = a - q*blo
|
||||
movl 24(%esp), %eax
|
||||
imull %edi, %eax // q*bhi
|
||||
subl %eax, %ecx // ECX:EBX = a - q*b
|
||||
sbbl $0, %edi // decrement q if remainder is negative
|
||||
xorl %edx, %edx
|
||||
movl %edi, %eax
|
||||
popl %edi
|
||||
popl %ebx
|
||||
retl
|
||||
|
||||
|
||||
1: // High word of a is greater than or equal to (b >> (1 + i)) on this branch
|
||||
|
||||
subl %ebx, %edx // subtract bhi from ahi so that divide will not
|
||||
divl %ebx // overflow, and find q and r such that
|
||||
//
|
||||
// ahi:alo = (1:q)*bhi + r
|
||||
//
|
||||
// Note that q is a number in (31-i).(1+i)
|
||||
// fix point.
|
||||
|
||||
pushl %edi
|
||||
notl %ecx
|
||||
shrl %eax
|
||||
orl $0x80000000, %eax
|
||||
shrl %cl, %eax // q = (1:qs) >> (1 + i)
|
||||
movl %eax, %edi
|
||||
mull 20(%esp) // q*blo
|
||||
movl 12(%esp), %ebx
|
||||
movl 16(%esp), %ecx // ECX:EBX = a
|
||||
subl %eax, %ebx
|
||||
sbbl %edx, %ecx // ECX:EBX = a - q*blo
|
||||
movl 24(%esp), %eax
|
||||
imull %edi, %eax // q*bhi
|
||||
subl %eax, %ecx // ECX:EBX = a - q*b
|
||||
sbbl $0, %edi // decrement q if remainder is negative
|
||||
xorl %edx, %edx
|
||||
movl %edi, %eax
|
||||
popl %edi
|
||||
popl %ebx
|
||||
retl
|
||||
|
||||
|
||||
9: // High word of b is zero on this branch
|
||||
|
||||
movl 12(%esp), %eax // Find qhi and rhi such that
|
||||
movl 16(%esp), %ecx //
|
||||
xorl %edx, %edx // ahi = qhi*b + rhi with 0 ≤ rhi < b
|
||||
divl %ecx //
|
||||
movl %eax, %ebx //
|
||||
movl 8(%esp), %eax // Find qlo such that
|
||||
divl %ecx //
|
||||
movl %ebx, %edx // rhi:alo = qlo*b + rlo with 0 ≤ rlo < b
|
||||
popl %ebx //
|
||||
retl // and return qhi:qlo
|
||||
|
||||
.text
|
||||
.balign 4
|
||||
.globl __umoddi3
|
||||
__umoddi3:
|
||||
|
||||
pushl %ebx
|
||||
movl 20(%esp), %ebx // Find the index i of the leading bit in b.
|
||||
bsrl %ebx, %ecx // If the high word of b is zero, jump to
|
||||
jz 9f // the code to handle that special case [9].
|
||||
|
||||
// High word of b is known to be non-zero on this branch
|
||||
|
||||
movl 16(%esp), %eax // Construct bhi, containing bits [1+i:32+i] of b
|
||||
|
||||
shrl %cl, %eax // Practically, this means that bhi is given by:
|
||||
shrl %eax //
|
||||
notl %ecx // bhi = (high word of b) << (31 - i) |
|
||||
shll %cl, %ebx // (low word of b) >> (1 + i)
|
||||
orl %eax, %ebx //
|
||||
movl 12(%esp), %edx // Load the high and low words of a, and jump
|
||||
movl 8(%esp), %eax // to [2] if the high word is larger than bhi
|
||||
cmpl %ebx, %edx // to avoid overflowing the upcoming divide.
|
||||
jae 2f
|
||||
|
||||
// High word of a is greater than or equal to (b >> (1 + i)) on this branch
|
||||
|
||||
divl %ebx // eax <-- qs, edx <-- r such that ahi:alo = bs*qs + r
|
||||
|
||||
pushl %edi
|
||||
notl %ecx
|
||||
shrl %eax
|
||||
shrl %cl, %eax // q = qs >> (1 + i)
|
||||
movl %eax, %edi
|
||||
mull 20(%esp) // q*blo
|
||||
movl 12(%esp), %ebx
|
||||
movl 16(%esp), %ecx // ECX:EBX = a
|
||||
subl %eax, %ebx
|
||||
sbbl %edx, %ecx // ECX:EBX = a - q*blo
|
||||
movl 24(%esp), %eax
|
||||
imull %edi, %eax // q*bhi
|
||||
subl %eax, %ecx // ECX:EBX = a - q*b
|
||||
|
||||
jnc 1f // if positive, this is the result.
|
||||
addl 20(%esp), %ebx // otherwise
|
||||
adcl 24(%esp), %ecx // ECX:EBX = a - (q-1)*b = result
|
||||
1: movl %ebx, %eax
|
||||
movl %ecx, %edx
|
||||
|
||||
popl %edi
|
||||
popl %ebx
|
||||
retl
|
||||
|
||||
|
||||
2: // High word of a is greater than or equal to (b >> (1 + i)) on this branch
|
||||
|
||||
subl %ebx, %edx // subtract bhi from ahi so that divide will not
|
||||
divl %ebx // overflow, and find q and r such that
|
||||
//
|
||||
// ahi:alo = (1:q)*bhi + r
|
||||
//
|
||||
// Note that q is a number in (31-i).(1+i)
|
||||
// fix point.
|
||||
|
||||
pushl %edi
|
||||
notl %ecx
|
||||
shrl %eax
|
||||
orl $0x80000000, %eax
|
||||
shrl %cl, %eax // q = (1:qs) >> (1 + i)
|
||||
movl %eax, %edi
|
||||
mull 20(%esp) // q*blo
|
||||
movl 12(%esp), %ebx
|
||||
movl 16(%esp), %ecx // ECX:EBX = a
|
||||
subl %eax, %ebx
|
||||
sbbl %edx, %ecx // ECX:EBX = a - q*blo
|
||||
movl 24(%esp), %eax
|
||||
imull %edi, %eax // q*bhi
|
||||
subl %eax, %ecx // ECX:EBX = a - q*b
|
||||
|
||||
jnc 3f // if positive, this is the result.
|
||||
addl 20(%esp), %ebx // otherwise
|
||||
adcl 24(%esp), %ecx // ECX:EBX = a - (q-1)*b = result
|
||||
3: movl %ebx, %eax
|
||||
movl %ecx, %edx
|
||||
|
||||
popl %edi
|
||||
popl %ebx
|
||||
retl
|
||||
|
||||
|
||||
|
||||
9: // High word of b is zero on this branch
|
||||
|
||||
movl 12(%esp), %eax // Find qhi and rhi such that
|
||||
movl 16(%esp), %ecx //
|
||||
xorl %edx, %edx // ahi = qhi*b + rhi with 0 ≤ rhi < b
|
||||
divl %ecx //
|
||||
movl %eax, %ebx //
|
||||
movl 8(%esp), %eax // Find rlo such that
|
||||
divl %ecx //
|
||||
movl %edx, %eax // rhi:alo = qlo*b + rlo with 0 ≤ rlo < b
|
||||
popl %ebx //
|
||||
xorl %edx, %edx // and return 0:rlo
|
||||
retl //
|
Loading…
Reference in New Issue
Block a user