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u-boot/arch/powerpc/lib/_lshrdi3.S

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SPDX: Convert all of our single license tags to Linux Kernel style When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-06 21:58:06 +00:00
/* SPDX-License-Identifier: GPL-2.0+ */
powerpc: Minimal private libgcc to build on Debian Standard Debian powerpc and powerpcspe systems only include hard-float libgcc in their native compilers, which causes scary build warnings when building U-Boot. Debian and other PowerPC-supporting distributions used to provide libgcc and other libraries in a "nof" (soft-float) form in the "multilib" packages. As they were completely unused by the distribution and therefore tended to be very buggy it was decided to save some time on the part of the maintainers and build-servers by removing them. Admittedly, right now the linker warnings do not indicate any problems, as the included routines do not use any floating point at all. The concern is that if floating-point code were ever added it might cause hard-float code to be unexpectedly included in U-Boot without generating a hard error. This would cause unexplained crashes or indeterminate results at runtime. The easiest way to resolve this is to borrow the routines that U-Boot needs from the Linux kernel, which has the same issue. Specifically, the routines are: _ashldi3(), _ashrdi3(), and _lshrdi3(). They were borrowed from arch/powerpc/kernel/misc_32.S as of v2.6.38-rc5, commit 85e2efbb1db9a18d218006706d6e4fbeb0216213, and are GPLv2+. The Makefile framework was copied from the U-Boot ARM port. Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com> Cc: Wolfgang Denk <wd@denx.de> Cc: Kim Phillips <kim.phillips@freescale.com> Cc: Andy Fleming <afleming@gmail.com> Cc: Kumar Gala <kumar.gala@freescale.com> Cc: Stefan Roese <sr@denx.de>
2011-02-23 06:40:38 +00:00
/*
* This code was copied from arch/powerpc/kernel/misc_32.S in the Linux
* kernel sources (commit 85e2efbb1db9a18d218006706d6e4fbeb0216213, also
* known as 2.6.38-rc5). The source file copyrights are as follows:
*
* (C) Copyright 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
* and Paul Mackerras.
*/
#include <ppc_asm.tmpl>
#include <ppc_defs.h>
#include <config.h>
/*
* Extended precision shifts.
*
* Updated to be valid for shift counts from 0 to 63 inclusive.
* -- Gabriel
*
* R3/R4 has 64 bit value
* R5 has shift count
* result in R3/R4
*
* ashrdi3: arithmetic right shift (sign propagation)
* lshrdi3: logical right shift
* ashldi3: left shift
*/
.globl __lshrdi3
__lshrdi3:
subfic r6,r5,32
srw r4,r4,r5 # LSW = count > 31 ? 0 : LSW >> count
addi r7,r5,32 # could be xori, or addi with -32
slw r6,r3,r6 # t1 = count > 31 ? 0 : MSW << (32-count)
srw r7,r3,r7 # t2 = count < 32 ? 0 : MSW >> (count-32)
or r4,r4,r6 # LSW |= t1
srw r3,r3,r5 # MSW = MSW >> count
or r4,r4,r7 # LSW |= t2
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