1/* 2 * This code was copied from arch/powerpc/kernel/misc_32.S in the Linux 3 * kernel sources (commit 85e2efbb1db9a18d218006706d6e4fbeb0216213, also 4 * known as 2.6.38-rc5). The source file copyrights are as follows: 5 * 6 * (C) Copyright 1995-1996 Gary Thomas (gdt@linuxppc.org) 7 * 8 * Largely rewritten by Cort Dougan (cort@cs.nmt.edu) 9 * and Paul Mackerras. 10 * 11 * SPDX-License-Identifier: GPL-2.0+ 12 */ 13 14#include <ppc_asm.tmpl> 15#include <ppc_defs.h> 16#include <config.h> 17 18/* 19 * Extended precision shifts. 20 * 21 * Updated to be valid for shift counts from 0 to 63 inclusive. 22 * -- Gabriel 23 * 24 * R3/R4 has 64 bit value 25 * R5 has shift count 26 * result in R3/R4 27 * 28 * ashrdi3: arithmetic right shift (sign propagation) 29 * lshrdi3: logical right shift 30 * ashldi3: left shift 31 */ 32 .globl __lshrdi3 33__lshrdi3: 34 subfic r6,r5,32 35 srw r4,r4,r5 # LSW = count > 31 ? 0 : LSW >> count 36 addi r7,r5,32 # could be xori, or addi with -32 37 slw r6,r3,r6 # t1 = count > 31 ? 0 : MSW << (32-count) 38 srw r7,r3,r7 # t2 = count < 32 ? 0 : MSW >> (count-32) 39 or r4,r4,r6 # LSW |= t1 40 srw r3,r3,r5 # MSW = MSW >> count 41 or r4,r4,r7 # LSW |= t2 42 blr 43